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Chakraborty S, Choudhury S, Singha NK. A New Class of Mechano-Responsive PolyureThane Via Anthracene -TAD Diels-Alder (DA) Click Chemistry. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024:e2406866. [PMID: 39258360 DOI: 10.1002/smll.202406866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2024] [Indexed: 09/12/2024]
Abstract
Smart or stimuli-responsive polymers have garnered significant interest in the scientific community due to their response to different stimuli like pH, temperature, light, mechanical force, etc. Mechanophoric polymer is an intriguing class of smart polymers that respond to external mechanical force by producing fluorescent moieties and can be utilized for damage detection and stress-sensing assessment. In recent reports on mechanophoric polymers, different mechanophoric motifs such as spiropyran, rhodamine, coumarin, etc. are explored. This investigation reports a new kind of mechanophoric polyurethane (PU) adduct based on Diels-Alder (DA) click chemistry. Here, an anthracene(An)-end capped tri-armed urethane system is synthesized, followed by a DA reaction using bis-(1,2,4-triazoline-3,5-dione) (bis-TAD) derivative. The incorporation of bis-TAD in the urethane system renders the anthracene inactive ("turn-off") by dismantling its conjugation as a result of a successful DA reaction. The soft PU translated into a harder material through bis-TAD linkages between polymer chains as evident from nanoindentation (NINT) analysis. The resulting material reverts back to its fluorescent "turned-on" mode owing to a force-accelerated retro-Diels-Alder (r-DA) reaction. Besides the mechanophoric attributes, the material demonstrates self-healing behavior examined by microscopic investigations. This innovative approach can be a potential route to design responsive polymers with dynamic functionalities for advanced material applications.
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Affiliation(s)
- Swadhin Chakraborty
- Rubber Technology Centre, Indian Institute of Technology, Kharagpur, 721302, India
| | - Soumyadip Choudhury
- Rubber Technology Centre, Indian Institute of Technology, Kharagpur, 721302, India
| | - Nikhil K Singha
- Rubber Technology Centre, Indian Institute of Technology, Kharagpur, 721302, India
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2
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Hertel R, Raisch M, Walter M, Reiter G, Sommer M. Mechanistically Different Mechanochromophores Enable Calibration and Validation of Molecular Forces in Glassy Polymers and Elastomeric Networks. Angew Chem Int Ed Engl 2024:e202409369. [PMID: 39136230 DOI: 10.1002/anie.202409369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2024] [Indexed: 10/18/2024]
Abstract
Sterically distorted donor-acceptor π-systems, termed DA springs, can be progressively planarized under mechanical load causing a bathochromic shift of the photoluminescence (PL) spectrum. By combining theory and experiment, we here use a simple linear force calibration for two different conformational mechanochromophores to determine molecular forces in polymers from the mechanochromic shift in PL wavelength during multiple uniaxial tensile tests. Two systems are used, i) a highly entangled linear glassy polyphenylene and ii) a covalent elastomeric polydimethylsiloxane network. The mean forces estimated by this method are validated using known threshold forces for the mechanochemical ring-opening reactions of two different spiropyran force probes. The agreement between both approaches underlines that these DA springs provide the unique opportunity for the online monitoring of local molecular forces present in diverse polymer matrices.
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Affiliation(s)
- Raphael Hertel
- Department of Polymer Chemistry, Institute for Chemistry, Chemnitz University of Technology, Str. der Nationen 62, 09111, Chemnitz, Germany
| | - Maximilian Raisch
- Department of Polymer Chemistry, Institute for Chemistry, Chemnitz University of Technology, Str. der Nationen 62, 09111, Chemnitz, Germany
| | - Michael Walter
- FIT Freiburg Center for Interactive Materials and Bioinspired Technologies, Albert-Ludwig-University of Freiburg, Georges-Köhler-Allee 105, 79110, Freiburg, Germany
| | - Günter Reiter
- Institute of Physics, Albert-Ludwig-University of Freiburg, Hermann-Herder-Str. 3, 79104, Freiburg, Germany
| | - Michael Sommer
- Department of Polymer Chemistry, Institute for Chemistry, Chemnitz University of Technology, Str. der Nationen 62, 09111, Chemnitz, Germany
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3
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Flear EJ, Horst M, Yang J, Xia Y. Force Transduction Through Distant Force-Bearing Regioisomeric Linkages Affects the Mechanochemical Reactivity of Cyclobutane. Angew Chem Int Ed Engl 2024; 63:e202406103. [PMID: 38818671 DOI: 10.1002/anie.202406103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2024] [Revised: 05/24/2024] [Accepted: 05/29/2024] [Indexed: 06/01/2024]
Abstract
Fundamental understanding of mechanochemical reactivity is important for designing new mechanophores. Besides the core structure of mechanophores, substituents on a mechanophore can affect its mechanochemical reactivity through electronic stabilization of the intermediate or effectiveness of force transduction from the polymer backbone to the mechanophore. The latter factor represents a unique mechanical effect in considering polymer mechanochemistry. Here, we show that regioisomeric linkage that is not directly adjacent to the first cleaving bond in cyclobutane can still significantly affect the mechanochemical reactivity of the mechanophore. We synthesized three non-scissile 1,2-diphenyl cyclobutanes, varying their linkage to the polymer backbone via the o, m, or p-position of the diphenyl substituents. Even though the regioisomers share the same substituted cyclobutane core structure and similar electronic stabilization of the diradical intermediate from cleaving the first C-C bond, the p isomer exhibited significantly higher mechanochemical reactivity than the o and m isomers. The observed difference in reactivity can be rationalized as the much more effective force transduction to the scissile bond through the p-position than the other two substitution positions. These findings point to the importance of considering force-bearing linkages that are more distant from the bond to be cleaved when incorporating mechanophores into polymer backbones.
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Affiliation(s)
- Erica J Flear
- Department of Chemistry, Stanford University Stanford, California, 94305, United States
| | - Matías Horst
- Department of Chemistry, Stanford University Stanford, California, 94305, United States
| | - Jinghui Yang
- Department of Chemistry, Stanford University Stanford, California, 94305, United States
| | - Yan Xia
- Department of Chemistry, Stanford University Stanford, California, 94305, United States
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4
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Liu J, Yang J, Xue B, Cao Y, Cheng W, Li Y. Understanding the Mechanochemistry of Mechano-Radicals in Self-Growth Materials by Single-Molecule Force Spectroscopy. Chemphyschem 2024; 25:e202300880. [PMID: 38705870 DOI: 10.1002/cphc.202300880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2023] [Revised: 04/02/2024] [Accepted: 05/03/2024] [Indexed: 05/07/2024]
Abstract
Recent research on mechano-radicals has provided valuable insights into self-growth and adaptive responsive materials. Typically, mechanophores must remain inert in the absence of force but respond quickly to external tension before other linkages within the polymer network. Azo compounds exhibit promising combinations of mechanical stability and force-triggered reactivity, making them widely used as mechano-radicals in force-responsive materials. However, the activation conditions and behavior of azo compounds have yet to be quantitatively explored. In this study, we investigated the mechanical strength of three azo compounds using single-molecule force spectroscopy. Our results revealed that these compounds exhibit rupture forces ranging from ~500 to 1000 pN, at a loading rate of 3×104 pN s-1. Importantly, these mechanophores demonstrate distinct kinetic properties. Their unique mechanical attributes enable azo bond scission and free radical generation before causing major polymer backbone damage of entire material during polymer network deformation. This fundamental understanding of mechanophores holds significant promise for the development of self-growth materials and their related applications.
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Affiliation(s)
- Jing Liu
- Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid-State Microstructure, Key Laboratory of Intelligent Optical Sensing and Manipulation, Ministry of Education, Department of Physics, Nanjing University, Nanjing, Jiangsu, 210093, China
| | - Jiahui Yang
- Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid-State Microstructure, Key Laboratory of Intelligent Optical Sensing and Manipulation, Ministry of Education, Department of Physics, Nanjing University, Nanjing, Jiangsu, 210093, China
| | - Bin Xue
- Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid-State Microstructure, Key Laboratory of Intelligent Optical Sensing and Manipulation, Ministry of Education, Department of Physics, Nanjing University, Nanjing, Jiangsu, 210093, China
| | - Yi Cao
- Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid-State Microstructure, Key Laboratory of Intelligent Optical Sensing and Manipulation, Ministry of Education, Department of Physics, Nanjing University, Nanjing, Jiangsu, 210093, China
| | - Wei Cheng
- Department of Oral Implantology, Nanjing Stomatological Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, 210008, China
| | - Yiran Li
- Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid-State Microstructure, Key Laboratory of Intelligent Optical Sensing and Manipulation, Ministry of Education, Department of Physics, Nanjing University, Nanjing, Jiangsu, 210093, China
- School of Chemistry and Chemical Engineering, Ningxia University, Yinchuan, Ningxia, 750021, China
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5
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Sun Y, Neary WJ, Huang X, Kouznetsova TB, Ouchi T, Kevlishvili I, Wang K, Chen Y, Kulik HJ, Craig SL, Moore JS. A Thermally Stable SO 2-Releasing Mechanophore: Facile Activation, Single-Event Spectroscopy, and Molecular Dynamic Simulations. J Am Chem Soc 2024; 146:10943-10952. [PMID: 38581383 DOI: 10.1021/jacs.4c02139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/08/2024]
Abstract
Polymers that release small molecules in response to mechanical force are promising candidates as next-generation on-demand delivery systems. Despite advancements in the development of mechanophores for releasing diverse payloads through careful molecular design, the availability of scaffolds capable of discharging biomedically significant cargos in substantial quantities remains scarce. In this report, we detail a nonscissile mechanophore built from an 8-thiabicyclo[3.2.1]octane 8,8-dioxide (TBO) motif that releases one equivalent of sulfur dioxide (SO2) from each repeat unit. The TBO mechanophore exhibits high thermal stability but is activated mechanochemically using solution ultrasonication in either organic solvent or aqueous media with up to 63% efficiency, equating to 206 molecules of SO2 released per 143.3 kDa chain. We quantified the mechanochemical reactivity of TBO by single-molecule force spectroscopy and resolved its single-event activation. The force-coupled rate constant for TBO opening reaches ∼9.0 s-1 at ∼1520 pN, and each reaction of a single TBO domain releases a stored length of ∼0.68 nm. We investigated the mechanism of TBO activation using ab initio steered molecular dynamic simulations and rationalized the observed stereoselectivity. These comprehensive studies of the TBO mechanophore provide a mechanically coupled mechanism of multi-SO2 release from one polymer chain, facilitating the translation of polymer mechanochemistry to potential biomedical applications.
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Affiliation(s)
- Yunyan Sun
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - William J Neary
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Xiao Huang
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Tatiana B Kouznetsova
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Tetsu Ouchi
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Ilia Kevlishvili
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Kecheng Wang
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Yingying Chen
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Department of Material Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Heather J Kulik
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Stephen L Craig
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Jeffrey S Moore
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
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6
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Thai LD, Kammerer JA, Mutlu H, Barner-Kowollik C. Photo- and halochromism of spiropyran-based main-chain polymers. Chem Sci 2024; 15:3687-3697. [PMID: 38455007 PMCID: PMC10915860 DOI: 10.1039/d3sc06383f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Accepted: 01/25/2024] [Indexed: 03/09/2024] Open
Abstract
Advanced functional polymeric materials based on spiropyrans (SPs) feature multi-stimuli responsive characteristics, such as a change in color with exposure to light (photochromism) or acids (halochromism). The inclusion of stimuli-responsive molecules in general - and SPs in particular - as main-chain repeating units is a scarcely explored macromolecular architecture compared to side chain responsive polymers. Herein, we establish the effects of substitution patterns on SPs within a homopolymer main-chain synthesized via head-to-tail Acyclic Diene METathesis (ADMET) polymerization. We unambiguously demonstrate that varying the location of the ester group (-OCOR) on the chromophore, which is essential to incorporate the SPs in the polymer backbone, determines the photo- and halochromism of the resulting polymers. While one polymer shows effective photochromism and resistance towards acids, the opposite - weak photochromism and effective response to acid - is observed for an isomeric polymer, simply by changing the position of the ester-linker relative to the benzopyran oxygen on the chromene unit. Our strategy represents a simple approach to manipulate the stimuli-response of main-chain SP bearing polymers and highlights the critical importance of isomeric molecular constitution on main-chain stimuli-sensitive polymers as emerging materials.
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Affiliation(s)
- Linh Duy Thai
- School of Chemistry and Physics, Queensland University of Technology (QUT) 2 George Street Brisbane QLD 4000 Australia
- Centre for Materials Science, Queensland University of Technology (QUT) 2 George Street Brisbane QLD 4000 Australia
- Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT) Hermann-von-Helmholtz-Platz 1 76344 Eggenstein-Leopoldshafen Germany
| | - Jochen A Kammerer
- School of Chemistry and Physics, Queensland University of Technology (QUT) 2 George Street Brisbane QLD 4000 Australia
- Centre for Materials Science, Queensland University of Technology (QUT) 2 George Street Brisbane QLD 4000 Australia
| | - Hatice Mutlu
- Institut de Science des Matériaux de Mulhouse, UMR 7361 CNRS/Université de Haute Alsace 15 Rue Jean Starcky Mulhouse Cedex 68057 France
| | - Christopher Barner-Kowollik
- School of Chemistry and Physics, Queensland University of Technology (QUT) 2 George Street Brisbane QLD 4000 Australia
- Centre for Materials Science, Queensland University of Technology (QUT) 2 George Street Brisbane QLD 4000 Australia
- Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT) Hermann-von-Helmholtz-Platz 1 76344 Eggenstein-Leopoldshafen Germany
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7
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Ding S, Wang W, Germann A, Wei Y, Du T, Meisner J, Zhu R, Liu Y. Bicyclo[2.2.0]hexene: A Multicyclic Mechanophore with Reactivity Diversified by External Forces. J Am Chem Soc 2024; 146:6104-6113. [PMID: 38377579 DOI: 10.1021/jacs.3c13589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2024]
Abstract
Polymer mechanochemistry has been established as an enabling tool in accessing chemical reactivity and reaction pathways that are distinctive from their thermal counterparts. However, eliciting diversified reaction pathways by activating different constituent chemical bonds from the same mechanophore structure remains challenging. Here, we report the design of a bicyclo[2.2.0]hexene (BCH) mechanophore to leverage its structural simplicity and relatively low molecular symmetry to demonstrate this idea of multimodal activation. Upon changing the attachment points of pendant polymer chains, three different C-C bonds in bicyclo[2.2.0]hexene are specifically activated via externally applied force by sonication. Experimental characterization confirms that in different scenarios of polymer attachment, the regioisomers of BCH undergo different activation reactions, entailing retro-[2+2] cycloreversion, 1,3-allylic migration, and retro-4π ring-opening reactions, respectively. Control experiments with small-molecule analogues reveal that the observed diversified reactivity of BCH regioisomers is possible only with mechanical force. Theoretical studies further elucidate that the differences in the positions of substitution between regioisomers have a minimal impact on the potential energy surface of the parent BCH scaffold. The mechanochemical selectivity between different C-C bonds in each constitutional isomer is a result of selective and effective coupling of force to the aligned C-C bond in each case.
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Affiliation(s)
- Shihao Ding
- Beijing National Laboratory for Molecular Sciences, Center for Soft Matter Science and Engineering, Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, and College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
| | - Wenkai Wang
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, and College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
| | - Anne Germann
- Institute for Physical Chemistry, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, Düsseldorf, 40225, Germany
| | - Yiting Wei
- Beijing National Laboratory for Molecular Sciences, Center for Soft Matter Science and Engineering, Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, and College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
| | - Tianyi Du
- Beijing National Laboratory for Molecular Sciences, Center for Soft Matter Science and Engineering, Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, and College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
| | - Jan Meisner
- Institute for Physical Chemistry, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, Düsseldorf, 40225, Germany
| | - Rong Zhu
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, and College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
| | - Yun Liu
- Beijing National Laboratory for Molecular Sciences, Center for Soft Matter Science and Engineering, Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, and College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
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8
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Qu W, Bi Z, Zou C, Chen C. Light, Heat, and Force-Responsive Polyolefins. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2307568. [PMID: 38183385 PMCID: PMC10953547 DOI: 10.1002/advs.202307568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 11/23/2023] [Indexed: 01/08/2024]
Abstract
Stimuli-responsive polymers have found applications as shape-memory materials, optical switches, and sensors, but the installation of these responsive properties in non-polar and inert polyolefins is challenging. In this contribution, a series of spiropyran (SP)-based comonomers are synthesized and copolymerized with ethylene or ethylene/cyclic monomers. In addition to great mechanical and surface properties, these functionalized polyolefins responded to light, heat, and force, which induced changes in the polymer structure to transmit color or mechanical signals. These interesting responsive properties are also installed in a series of commercial polyolefin materials through reactive extrusion, making the scalable production of these materials possible.
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Affiliation(s)
- Weicheng Qu
- Key Laboratory of Precision and Intelligent ChemistryDepartment of Polymer Science and EngineeringUniversity of Science and Technology of ChinaHefei230026China
| | - Zhengxing Bi
- Key Laboratory of Precision and Intelligent ChemistryDepartment of Polymer Science and EngineeringUniversity of Science and Technology of ChinaHefei230026China
| | - Chen Zou
- Key Laboratory of Precision and Intelligent ChemistryDepartment of Polymer Science and EngineeringUniversity of Science and Technology of ChinaHefei230026China
| | - Changle Chen
- Key Laboratory of Precision and Intelligent ChemistryDepartment of Polymer Science and EngineeringUniversity of Science and Technology of ChinaHefei230026China
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9
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Lin Y, Kouznetsova TB, Foret AG, Craig SL. Solvent Polarity Effects on the Mechanochemistry of Spiropyran Ring Opening. J Am Chem Soc 2024; 146:3920-3925. [PMID: 38308653 DOI: 10.1021/jacs.3c11621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2024]
Abstract
The spiropyran mechanophore (SP) is employed as a reporter of molecular tension in a wide range of polymer matrices, but the influence of surrounding environment on the force-coupled kinetics of its ring opening has not been quantified. Here, we report single-molecule force spectroscopy studies of SP ring opening in five solvents that span normalized Reichardt solvent polarity factors (ETN) of 0.1-0.59. Individual multimechanophore polymers were activated under increasing tension at constant 300 nm s-1 displacement in an atomic force microscope. The extension results in a plateau in the force-extension curve, whose midpoint occurs at a transition force f* that corresponds to the force required to increase the rate constant of SP activation to approximately 30 s-1. More polar solvents lead to mechanochemical reactions that are easier to trigger; f* decreases across the series of solvents, from a high of 415 ± 13 pN in toluene to a low of 234 ± 9 pN in n-butanol. The trend in mechanochemical reactivity is consistent with the developing zwitterionic character on going from SP to the ring-opened merocyanine product. The force dependence of the rate constant (Δx‡) was calculated for all solvent cases and found to increase with ETN, which is interpreted to reflect a shift in the transition state to a later and more productlike position. The inferred shift in the transition state position is consistent with a double-well (two-step) reaction potential energy surface, in which the second step is rate determining, and the intermediate is more polar than the product.
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Affiliation(s)
- Yangju Lin
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Tatiana B Kouznetsova
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Alex G Foret
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Stephen L Craig
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
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10
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Bhuiyan FH, Li YS, Kim SH, Martini A. Shear-activation of mechanochemical reactions through molecular deformation. Sci Rep 2024; 14:2992. [PMID: 38316829 PMCID: PMC10844542 DOI: 10.1038/s41598-024-53254-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 01/30/2024] [Indexed: 02/07/2024] Open
Abstract
Mechanical stress can directly activate chemical reactions by reducing the reaction energy barrier. A possible mechanism of such mechanochemical activation is structural deformation of the reactant species. However, the effect of deformation on the reaction energetics is unclear, especially, for shear stress-driven reactions. Here, we investigated shear stress-driven oligomerization reactions of cyclohexene on silica using a combination of reactive molecular dynamics simulations and ball-on-flat tribometer experiments. Both simulations and experiments captured an exponential increase in reaction yield with shear stress. Elemental analysis of ball-on-flat reaction products revealed the presence of oxygen in the polymers, a trend corroborated by the simulations, highlighting the critical role of surface oxygen atoms in oligomerization reactions. Structural analysis of the reacting molecules in simulations indicated the reactants were deformed just before a reaction occurred. Quantitative evidence of shear-induced deformation was established by comparing bond lengths in cyclohexene molecules in equilibrium and prior to reactions. Nudged elastic band calculations showed that the deformation had a small effect on the transition state energy but notably increased the reactant state energy, ultimately leading to a reduction in the energy barrier. Finally, a quantitative relationship was developed between molecular deformation and energy barrier reduction by mechanical stress.
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Affiliation(s)
- Fakhrul H Bhuiyan
- Department of Mechanical Engineering, University of California Merced, 5200 N. Lake Road, Merced, CA, 95343, USA
| | - Yu-Sheng Li
- Department of Chemical Engineering and Materials Research Institute, Pennsylvania State University, University Park, PA, 16802, USA
| | - Seong H Kim
- Department of Chemical Engineering and Materials Research Institute, Pennsylvania State University, University Park, PA, 16802, USA
| | - Ashlie Martini
- Department of Mechanical Engineering, University of California Merced, 5200 N. Lake Road, Merced, CA, 95343, USA.
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11
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Thai LD, Fanelli J, Munaweera R, O'Mara ML, Barner-Kowollik C, Mutlu H. Main-chain Macromolecular Hydrazone Photoswitches. Angew Chem Int Ed Engl 2024; 63:e202315887. [PMID: 37988197 DOI: 10.1002/anie.202315887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 11/16/2023] [Accepted: 11/17/2023] [Indexed: 11/23/2023]
Abstract
Hydrazones-consisting of a dynamic imine bond and an acidic NH proton-have recently emerged as versatile photoswitches underpinned by their ability to form thermally bistable isomers, (Z) and (E), respectively. Herein, we introduce two photoresponsive homopolymers containing structurally different hydrazones as main-chain repeating units, synthesized via head-to-tail Acyclic Diene METathesis (ADMET) polymerization. Their key difference lies in the hydrazone design, specifically the location of the aliphatic arm connecting the rotor of the hydrazone photoswitch to the aliphatic polymer backbone. Critically, we demonstrate that their main photoresponsive property, i.e., their hydrodynamic volume, changes in opposite directions upon photoisomerization (λ=410 nm) in dilute solution. Further, the polymers-independent of the design of the individual hydrazone monomer-feature a photoswitchable glass transition temperature (Tg ) by close to 10 °C. The herein established design strategy allows to photochemically manipulate macromolecular properties by simple structural changes.
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Affiliation(s)
- Linh Duy Thai
- School of Chemistry and Physics, Queensland University of Technology (QUT), 2 George Street, 4000, Brisbane, QLD, Australia
- Centre for Materials Science, Queensland University of Technology (QUT), 2 George Street, 4000, Brisbane, QLD, Australia
- Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
| | - Julian Fanelli
- School of Chemistry and Physics, Queensland University of Technology (QUT), 2 George Street, 4000, Brisbane, QLD, Australia
- Centre for Materials Science, Queensland University of Technology (QUT), 2 George Street, 4000, Brisbane, QLD, Australia
- Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
- Soft Matter Synthesis Laboratory, Institute for Biological Interfaces 3, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
| | - Rangika Munaweera
- Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland (UQ), 4067, St Lucia, QLD, Australia
| | - Megan L O'Mara
- Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland (UQ), 4067, St Lucia, QLD, Australia
| | - Christopher Barner-Kowollik
- School of Chemistry and Physics, Queensland University of Technology (QUT), 2 George Street, 4000, Brisbane, QLD, Australia
- Centre for Materials Science, Queensland University of Technology (QUT), 2 George Street, 4000, Brisbane, QLD, Australia
- Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
| | - Hatice Mutlu
- Institut de Science des Matériaux de Mulhouse (IS2M), UMR 7361 CNRS/, Université de Haute Alsace (UHA), 15 rue Jean Starcky, 68057, Mulhouse Cedex, France
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12
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Horst M, Meisner J, Yang J, Kouznetsova TB, Craig SL, Martínez TJ, Xia Y. Mechanochemistry of Pterodactylane. J Am Chem Soc 2024; 146:884-891. [PMID: 38131266 DOI: 10.1021/jacs.3c11293] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
Pterodactylane is a [4]-ladderane with substituents on the central rung. Comparing the mechanochemistry of the [4]-ladderane structure when pulled from the central rung versus the end rung revealed a striking difference in the threshold force of mechanoactivation: the threshold force is dramatically lowered from 1.9 nN when pulled on the end rung to 0.7 nN when pulled on the central rung. We investigated the bicyclic products formed from the mechanochemical activation of pterodactylane experimentally and computationally, which are distinct from the mechanochemical products of ladderanes being activated from the end rung. We compared the products of pterodactylane's mechanochemical and thermal activation to reveal differences and similarities in the mechanochemical and thermal pathways of pterodactylane transformation. Interestingly, we also discovered the presence of elementary steps that are accelerated or suppressed by force within the same mechanochemical reaction of pterodactylane, suggesting rich mechanochemical manifolds of multicyclic structures. We rationalized the greatly enhanced mechanochemical reactivity of the central rung of pterodactylane and discovered force-free ground state bond length to be a good low-cost predictor of the threshold force for cyclobutane-based mechanophores. These findings advance our understanding of mechanochemical reactivities and pathways, and they will guide future designs of mechanophores with low threshold forces to facilitate their applications in force-responsive materials.
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Affiliation(s)
- Matías Horst
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Jan Meisner
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
- Institute for Physical Chemistry, Department of Chemistry, Heinrich-Heine-Universität Düsseldorf, Düsseldorf D-40225, Germany
| | - Jinghui Yang
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Tatiana B Kouznetsova
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Stephen L Craig
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Todd J Martínez
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Yan Xia
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
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13
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Zeng T, Ordner LA, Liu P, Robb MJ. Multimechanophore Polymers for Mechanically Triggered Small Molecule Release with Ultrahigh Payload Capacity. J Am Chem Soc 2024; 146:95-100. [PMID: 38157405 PMCID: PMC10786027 DOI: 10.1021/jacs.3c11927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 12/16/2023] [Accepted: 12/26/2023] [Indexed: 01/03/2024]
Abstract
Polymers that release small molecules in response to mechanical force are promising for a variety of applications including drug delivery, catalysis, and sensing. While a number of mechanophores have been developed for the release of covalently bound payloads, existing strategies are either limited in cargo scope or, in the case of more general mechanophore designs, are restricted to the release of one or two cargo molecules per polymer chain. Herein, we introduce a nonscissile mechanophore based on a masked 2-furylcarbinol derivative that enables the preparation of multimechanophore polymers with ultrahigh payload capacity. We demonstrate that polymers prepared via ring-opening metathesis polymerization are capable of releasing hundreds of small-molecule payloads per polymer chain upon ultrasound-induced mechanochemical activation. This nonscissile masked 2-furylcarbinol mechanophore overcomes a major challenge in cargo loading capacity associated with previous 2-furylcarbinol mechanophore designs, enabling applications that benefit from much higher concentrations of delivered cargo.
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Affiliation(s)
- Tian Zeng
- Division of Chemistry and
Chemical Engineering, California Institute
of Technology, Pasadena, California 91125, United States
| | - Liam A. Ordner
- Division of Chemistry and
Chemical Engineering, California Institute
of Technology, Pasadena, California 91125, United States
| | - Peng Liu
- Division of Chemistry and
Chemical Engineering, California Institute
of Technology, Pasadena, California 91125, United States
| | - Maxwell J. Robb
- Division of Chemistry and
Chemical Engineering, California Institute
of Technology, Pasadena, California 91125, United States
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14
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Alonso M, Bettens T, Eeckhoudt J, Geerlings P, De Proft F. Wandering through quantum-mechanochemistry: from concepts to reactivity and switches. Phys Chem Chem Phys 2023; 26:21-35. [PMID: 38086672 DOI: 10.1039/d3cp04907h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2023]
Abstract
Mechanochemistry has experienced a renaissance in recent years witnessing, at the molecular level, a remarkable interplay between theory and experiment. Molecular mechanochemistry has welcomed a broad spectrum of quantum-chemical methods to evaluate the influence of an external mechanical force on molecular properties. In this contribution, an overview is given on recent work on quantum mechanochemistry in the Brussels Quantum Chemistry group (ALGC). The effect of an external force was scrutinized both in fundamental topics, like reactivity descriptors in Conceptual DFT, and in applied topics, such as designing molecular force probes and tuning the stereoselectivity of certain types of reactions. In the conceptual part, a brief overview of the techniques introducing mechanical forces into a quantum-mechanical description of a molecule is followed by an introduction to conceptual DFT. The evolution of the electronic chemical potential (or electronegativity), chemical hardness and electrophilicity are investigated when a chemical bond in a series of diatomics is put under mechanical stress. Its counterpart, the influence of mechanical stress on bond angles, is analyzed by varying the strain present in alkyne triple bonds by applying a bending force, taking the strain promoted alkyne-azide coupling cycloaddition as an example. The increase of reactivity of the alkyne upon bending is probed by Fukui functions and the local softness. In the applied part, a new molecular force probe is presented based on an intramolecular 6π-electrocyclization in constrained polyenes operating under thermal conditions. A cyclic process is conceived where ring opening and closure are triggered by applying or removing an external pulling force. The efficiency of mechanical activation strongly depends on the magnitude of the applied force and the distance between the pulling points. The idea of pulling point distances as a tool to identify new mechanochemical processes is then tested in [28]hexaphyrins with an intricate equilibrium between Möbius aromatic and Hückel antiaromatic topologies. A mechanical force is shown to trigger the interconversion between the two topologies, using the distance matrix as a guide to select appropriate pulling points. In a final application, the Felkin-Anh model for the addition of nucleophiles to chiral carbonyls under the presence of an external mechanical force is scrutinized. By applying a force for restricting the conformational freedom of the chiral ketone, otherwise inaccessible reaction pathways are promoted on the force-modified potential energy surfaces resulting in a diastereoselectivity different from the force-free reaction.
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Affiliation(s)
- Mercedes Alonso
- Eenheid Algemene Chemie (ALGC), Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Brussels, Belgium.
| | - Tom Bettens
- Eenheid Algemene Chemie (ALGC), Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Brussels, Belgium.
| | - Jochen Eeckhoudt
- Eenheid Algemene Chemie (ALGC), Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Brussels, Belgium.
| | - Paul Geerlings
- Eenheid Algemene Chemie (ALGC), Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Brussels, Belgium.
| | - Frank De Proft
- Eenheid Algemene Chemie (ALGC), Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Brussels, Belgium.
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15
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Suga K, Yamakado T, Saito S. Dual Ratiometric Fluorescence Monitoring of Mechanical Polymer Chain Stretching and Subsequent Strain-Induced Crystallization. J Am Chem Soc 2023. [PMID: 38051032 DOI: 10.1021/jacs.3c09175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2023]
Abstract
Tracking the behavior of mechanochromic molecules provides valuable insights into force transmission and associated microstructural changes in soft materials under load. Herein, we report a dual ratiometric fluorescence (FL) analysis for monitoring both mechanical polymer chain stretching and strain-induced crystallization (SIC) of polymers. SIC has recently attracted renewed attention as an effective mechanism for improving the mechanical properties of polymers. A polyurethane (PU) film incorporating a trace of a dual-emissive flapping force probe (N-FLAP, 0.008 wt %) exhibited a blue-to-green FL spectral change in a low-stress region (<20 MPa), resulting from conformational planarization of the probe in mechanically stretched polymer chains. More importantly, at higher probe concentrations (∼0.65 wt %), the PU film showed a second spectral change from green to yellow during the SIC growth (20-65 MPa) due to self-absorption of scattered FL in a short wavelength region. The reversibility of these spectral changes was demonstrated by load-unload cycles. With these results in hand, the degrees of the polymer chain stretching and the SIC were quantitatively mapped and monitored by dual ratiometric imaging based on different FL ratios (I525/I470 and I525/I600). Simultaneous analysis of these two mappings revealed a spatiotemporal gap in the distribution of the polymer chain stretching and the SIC. The combinational use of the dual-emissive force probe and the ratiometric FL imaging is a universal approach for the development of soft matter physics.
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Affiliation(s)
- Kensuke Suga
- Graduate School of Science, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan
| | - Takuya Yamakado
- Graduate School of Science, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan
| | - Shohei Saito
- Graduate School of Science, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan
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16
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Cai Y, Binder WH. Triggered Crosslinking of Main-Chain Enediyne Polyurethanes via Bergman Cyclization. Macromol Rapid Commun 2023; 44:e2300440. [PMID: 37877520 DOI: 10.1002/marc.202300440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 10/23/2023] [Indexed: 10/26/2023]
Abstract
Crosslinking chemistries occupy an important position in polymer modification with a particular importance when triggered in response to external stimuli. Enediyne (EDY) moieties are used as functional entities in this work, known to undergo a pericyclic Bergman cyclization (BC) to induce a triggered crosslinking of polyurethanes (PU) via the intermediately formed diradicals. Diamino-EDYs, where the distance between the enyne-moieties is known to be critical to induce a BC, are placed repetitively as main-chain structural elements in isophorone-based PUs to induce reinforcement upon heating, compression, or stretching. A 7-day compression under room temperature results in a ≈69% activation of the BC, together with the observation of an increase in tensile strength by 62% after 25 stretching cycles. The occurrence of BC is further proven by the decreased exothermic values in differential scanning calorimetry, together with characteristic peaks of the formed benzene moieties via IR spectroscopy. Purely heat-induced crosslinking contributes to 191% of the maximum tensile strength in comparison to the virgin PU. The BC herein forms an excellent crosslinking strategy, triggered by heat or force in PU materials.
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Affiliation(s)
- Yue Cai
- Macromolecular Chemistry, Institute of Chemistry, Faculty of Natural Science II, Martin Luther University Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120, Halle (Saale), Germany
| | - Wolfgang H Binder
- Macromolecular Chemistry, Institute of Chemistry, Faculty of Natural Science II, Martin Luther University Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120, Halle (Saale), Germany
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17
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Buche MR, Rimsza JM. Modeling single-molecule stretching experiments using statistical thermodynamics. Phys Rev E 2023; 108:064503. [PMID: 38243517 DOI: 10.1103/physreve.108.064503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 11/30/2023] [Indexed: 01/21/2024]
Abstract
Single-molecule stretching experiments are widely utilized within the fields of physics and chemistry to characterize the mechanics of individual bonds or molecules, as well as chemical reactions. Analytic relations describing these experiments are valuable, and these relations can be obtained through the statistical thermodynamics of idealized model systems representing the experiments. Since the specific thermodynamic ensembles manifested by the experiments affect the outcome, primarily for small molecules, the stretching device must be included in the idealized model system. Though the model for the stretched molecule might be exactly solvable, including the device in the model often prevents analytic solutions. In the limit of large or small device stiffness, the isometric or isotensional ensembles can provide effective approximations, but the device effects are missing. Here a dual set of asymptotically correct statistical thermodynamic theories are applied to develop accurate approximations for the full model system that includes both the molecule and the device. The asymptotic theories are first demonstrated to be accurate using the freely jointed chain model and then using molecular dynamics calculations of a single polyethylene chain.
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Affiliation(s)
- Michael R Buche
- Computational Solid Mechanics and Structural Dynamics, Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
| | - Jessica M Rimsza
- Geochemistry, Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
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18
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McFadden ME, Barber RW, Overholts AC, Robb MJ. Naphthopyran molecular switches and their emergent mechanochemical reactivity. Chem Sci 2023; 14:10041-10067. [PMID: 37772118 PMCID: PMC10530568 DOI: 10.1039/d3sc03729k] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 08/23/2023] [Indexed: 09/30/2023] Open
Abstract
Naphthopyran molecular switches undergo a ring-opening reaction upon external stimulation to generate intensely colored merocyanine dyes. Their unique modularity and synthetic accessibility afford exceptional control over their properties and stimuli-responsive behavior. Commercial applications of naphthopyrans as photoswitches in photochromic ophthalmic lenses have spurred an extensive body of work exploring naphthopyran-merocyanine structure-property relationships. The recently discovered mechanochromic behavior of naphthopyrans has led to their emergent application in the field of polymer mechanochemistry, enabling advances in the design of force-responsive materials as well as fundamental insights into mechanochemical reactivity. The structure-property relationships established in the photochemical literature serve as a convenient blueprint for the design of naphthopyran molecular force probes with precisely tuned properties. On the other hand, the mechanochemical reactivity of naphthopyran diverges in many cases from the conventional photochemical pathways, resulting in unexpected properties and opportunities for deeper understanding and innovation in polymer mechanochemistry. Here, we highlight the features of the naphthopyran scaffold that render it a powerful platform for the design of mechanochromic materials and review recent advances in naphthopyran mechanochemistry.
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Affiliation(s)
- Molly E McFadden
- Division of Chemistry and Chemical Engineering, California Institute of Technology Pasadena California 91125 USA
| | - Ross W Barber
- Division of Chemistry and Chemical Engineering, California Institute of Technology Pasadena California 91125 USA
| | - Anna C Overholts
- Division of Chemistry and Chemical Engineering, California Institute of Technology Pasadena California 91125 USA
| | - Maxwell J Robb
- Division of Chemistry and Chemical Engineering, California Institute of Technology Pasadena California 91125 USA
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19
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Ditzler RAJ, King AJ, Towell SE, Ratushnyy M, Zhukhovitskiy AV. Editing of polymer backbones. Nat Rev Chem 2023; 7:600-615. [PMID: 37542179 DOI: 10.1038/s41570-023-00514-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/12/2023] [Indexed: 08/06/2023]
Abstract
Polymers are at the epicentre of modern technological progress and the associated environmental pollution. Considerations of both polymer functionality and lifecycle are crucial in these contexts, and the polymer backbone - the core of a polymer - is at the root of these considerations. Just as the meaning of a sentence can be altered by editing its words, the function and sustainability of a polymer can also be transformed via the chemical modification of its backbone. Yet, polymer modification has primarily been focused on the polymer periphery. In this Review, we focus on the transformations of the polymer backbone by defining some concepts fundamental to this topic (for example, 'polymer backbone' and 'backbone editing') and by collecting and categorizing examples of backbone editing scattered throughout a century's worth of chemical literature, and outline critical directions for further research. In so doing, we lay the foundation for the field of polymer backbone editing and hope to accelerate its development.
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Affiliation(s)
- Rachael A J Ditzler
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Andrew J King
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Sydney E Towell
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Maxim Ratushnyy
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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20
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Wang J, Kouznetsova TB, Xia J, Ángeles FJ, de la Cruz MO, Craig SL. A polyelectrolyte handle for single‐molecule force spectroscopy. JOURNAL OF POLYMER SCIENCE 2023. [DOI: 10.1002/pol.20230051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/12/2023]
Affiliation(s)
- Junpeng Wang
- Department of Chemistry Duke University Durham North Carolina USA
| | | | - Jianshe Xia
- Department of Materials Science and Engineering Northwestern University Evanston Illinois USA
| | - Felipe Jiménez Ángeles
- Department of Materials Science and Engineering Northwestern University Evanston Illinois USA
| | | | - Stephen L. Craig
- Department of Chemistry Duke University Durham North Carolina USA
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21
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Spiropyran-containing water-soluble and photoreversible copolymers. POLYMER 2023. [DOI: 10.1016/j.polymer.2023.125827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
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22
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Walter M, Linsler D, König T, Gäbert C, Reinicke S, Moseler M, Mayrhofer L. Mechanochemical Activation of Anthracene [4+4] Cycloadducts. J Phys Chem Lett 2023; 14:1445-1451. [PMID: 36734822 DOI: 10.1021/acs.jpclett.2c03493] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Controlled formation and breaking of weak chemical bonds is a versatile method for modifying the properties of materials. Anthracene [4+4] cycloadducts are a prime example that can be formed by light and opened by external forces. We address the theoretical description of mechanochemistry of these cycloadducts, where the standard constraint geometry simulates forces approach fails due to the lack of consideration of temperature. Explicit inclusion of external forces reveals the corresponding transition barriers that are clearly dominated by rupture of the [4+4] inter-anthracene bonds. Other bonds come into play at extremely large forces only, which cannot be expected to be reached under ambient conditions. The theoretical results are in line with the experimental rheology of [4+4]-linked anthracene polymers, which indicates reversible re-formation of [4+4] cycloaddition bonds with ultraviolet light after mechanochemical bond breaking due to applied shear stress.
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Affiliation(s)
- Michael Walter
- Fraunhofer IWM, MikroTribologie Centrum μTC, 76131Karlsruhe, Germany
- FIT Freiburg Centre for Interactive Materials and Bioinspired Technologies, University of Freiburg, 79085Freiburg, Germany
- Cluster of Excellence livMatS@FIT, 79110Freiburg, Germany
| | - Dominic Linsler
- Fraunhofer IWM, MikroTribologie Centrum μTC, 76131Karlsruhe, Germany
| | - Tobias König
- Fraunhofer IWM, MikroTribologie Centrum μTC, 76131Karlsruhe, Germany
| | | | | | - Michael Moseler
- Fraunhofer IWM, MikroTribologie Centrum μTC, 76131Karlsruhe, Germany
- Cluster of Excellence livMatS@FIT, 79110Freiburg, Germany
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23
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Chen C, Du S, Taylor JM, Huang J, Evans CM, Braun PV. Visualizing ion transport in polymers via ion-chromic indicators. ACS Macro Lett 2023; 12:86-92. [PMID: 36595317 DOI: 10.1021/acsmacrolett.2c00651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
There is growing interest in polymers with high ionic conductivity for applications including batteries, fuel cells, and separation membranes. However, measuring ion diffusion in polymers can be challenging, requiring complex procedures and instrumentation. Here, a simple strategy to study ion diffusion in polymers is presented that utilizes ion-chromic spiropyan as an indicator to measure the diffusion of LiTFSI, KTFSI, and NaTFSI within poly(ethylene oxide)-based polymer networks. These systems are selected, as these are common ions and polymers used in energy storage applications, however, the approach described is not specific to materials for energy storage. Specifically, to enabling the study of ion diffusion, these salts cause the spiropyran to undergo an isomerization reaction, which results in a significant color change. This colorimetric response enables the determination of the diffusion coefficients of these ions within films of these polymers simply by optically tracking the spatial-temporal evolution of the isomerization product within the film and fitting the data to the relevant diffusion equations. The simplicity of the method makes it amenable to the study of ion diffusion in polymers under a range of conditions, including various temperatures and under macroscopic deformation.
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Affiliation(s)
- Chen Chen
- Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, Urbana, Illinois61801, United States.,Department of Materials Science and Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois61801, United States.,Materials Research Laboratory, University of Illinois Urbana-Champaign, Urbana, Illinois61801, United States
| | - Sifei Du
- Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, Urbana, Illinois61801, United States.,Department of Chemistry, University of Illinois Urbana-Champaign, Urbana, Illinois61801, United States.,Materials Research Laboratory, University of Illinois Urbana-Champaign, Urbana, Illinois61801, United States
| | - Jay M Taylor
- Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, Urbana, Illinois61801, United States.,Materials Research Laboratory, University of Illinois Urbana-Champaign, Urbana, Illinois61801, United States
| | - Junrou Huang
- Department of Chemistry, University of Illinois Urbana-Champaign, Urbana, Illinois61801, United States.,Materials Research Laboratory, University of Illinois Urbana-Champaign, Urbana, Illinois61801, United States
| | - Christopher M Evans
- Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, Urbana, Illinois61801, United States.,Department of Materials Science and Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois61801, United States.,Materials Research Laboratory, University of Illinois Urbana-Champaign, Urbana, Illinois61801, United States
| | - Paul V Braun
- Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, Urbana, Illinois61801, United States.,Department of Materials Science and Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois61801, United States.,Department of Chemistry, University of Illinois Urbana-Champaign, Urbana, Illinois61801, United States.,Materials Research Laboratory, University of Illinois Urbana-Champaign, Urbana, Illinois61801, United States
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24
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Craig SL. Concluding remarks: Fundamentals, applications and future of mechanochemistry. Faraday Discuss 2023; 241:485-491. [PMID: 36472143 DOI: 10.1039/d2fd00141a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This paper provides a summary of the Faraday Discussions meeting on "Mechanochemistry: fundamentals, applications, and future" in the context of broad themes whose exploration might contribute to a unified framework of mechanochemical phenomena.
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Affiliation(s)
- Stephen L Craig
- Department of Chemistry, Duke University, Durham, NC 27708-0346, USA.
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25
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Janissen R, Filonenko GA. Mechanochemistry of Spiropyran under Internal Stresses of a Glassy Polymer. J Am Chem Soc 2022; 144:23198-23204. [PMID: 36509594 PMCID: PMC9782785 DOI: 10.1021/jacs.2c11280] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Mechanophores are powerful molecular tools used to track bond rupture and characterize mechanical damage in polymers. The majority of mechanophores are known to respond to external stresses, and we report in this study the first precedent of a mechanochemical response to internal, residual stresses that accumulate during polymer vitrification. While internal stress is intrinsic to polymers that can form solids, we demonstrate that it can dramatically affect the mechanochemistry of spiropyran probes and alter their intramolecular isomerization barriers by up to 70 kJ mol-1. This new behavior of spiropyrans (SPs) enables their application for analysis of internal stresses distribution and their mechanochemical characterization on the molecular level. Spectroscopy and imaging based on SP mechanochemistry showed high topological sensitivity and allowed us to discern different levels of internal stress impacting various locations along the polymer chain. The nature of the developed technique allows for wide-field imaging of stress heterogeneities in polymer samples of irregular shapes and dimensions, making it feasible to directly observe molecular-level manifestations of mechanical stresses that accompany the formation of a vast number of solid polymers.
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Affiliation(s)
- Richard Janissen
- Single-Molecule
Biophysics, Department of Bionanoscience, Delft University of Technology, van der Maasweg 9, Delft 2629HZ, The Netherlands
| | - Georgy A. Filonenko
- Department
of Materials Science and Engineering, Delft
University of Technology, Mekelweg 2, Delft 2628
CD, The Netherlands,
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26
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Huo Z, Skala SJ, Falck LR, Laaser JE, Statt A. Computational Study of Mechanochemical Activation in Nanostructured Triblock Copolymers. ACS POLYMERS AU 2022; 2:467-477. [PMID: 36536889 PMCID: PMC9756960 DOI: 10.1021/acspolymersau.2c00031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 08/10/2022] [Accepted: 08/11/2022] [Indexed: 06/17/2023]
Abstract
Force-driven chemical reactions have emerged as an attractive platform for diverse applications in polymeric materials. However, the microscopic chain conformations and topologies necessary for efficiently transducing macroscopic forces to the molecular scale are not well-understood. In this work, we use a coarse-grained model to investigate the impact of network-like topologies on mechanochemical activation in self-assembled triblock copolymers. We find that mechanochemical activation during tensile deformation depends strongly on both the polymer composition and chain conformation in these materials. Activation primarily occurs in the tie chains connecting different glassy domains and in loop chains that are hooked onto each other by physical entanglements. Activation also requires a higher stress in materials having a higher glassy block content. Overall, the lamellar samples show the highest percent activation at high stress. In contrast, at low stress, the spherical morphology, which has the lowest glassy fraction, shows the highest activation. Additionally, we observe a spatial pattern of activation, which appears to be tied to distortion of the self-assembled morphology. Higher activation is observed in the tips of the chevrons formed during deformation of lamellar samples as well as in the centers between the cylinders in the cylindrical morphology. Our work shows that changes in the network-like topology in different morphologies significantly impact mechanochemical activation efficiencies in these materials, suggesting that this area will be a fruitful avenue for further experimental research.
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Affiliation(s)
- Zijian Huo
- Department
of Chemistry, University of Pittsburgh, 219 Parkman Ave., Pittsburgh, Pennsylvania 15260, United States
| | - Stephen J Skala
- Materials
Science and Engineering, Grainger College of Engineering, University of Illinois, Urbana−Champaign, Illinois 61801, United States
| | - Lavinia R Falck
- Department
of Chemistry, University of Pittsburgh, 219 Parkman Ave., Pittsburgh, Pennsylvania 15260, United States
| | - Jennifer E Laaser
- Department
of Chemistry, University of Pittsburgh, 219 Parkman Ave., Pittsburgh, Pennsylvania 15260, United States
| | - Antonia Statt
- Materials
Science and Engineering, Grainger College of Engineering, University of Illinois, Urbana−Champaign, Illinois 61801, United States
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27
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Wang L, Zheng X, Kouznetsova TB, Yen T, Ouchi T, Brown CL, Craig SL. Mechanochemistry of Cubane. J Am Chem Soc 2022; 144:22865-22869. [DOI: 10.1021/jacs.2c10878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Liqi Wang
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Xujun Zheng
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | | | - Tiffany Yen
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Tetsu Ouchi
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Cameron L. Brown
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Stephen L. Craig
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
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28
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Hertel R, Maftuhin W, Walter M, Sommer M. Conformer Ring Flip Enhances Mechanochromic Performance of ansa-Donor-Acceptor-Donor Mechanochromic Torsional Springs. J Am Chem Soc 2022; 144:21897-21907. [PMID: 36414534 DOI: 10.1021/jacs.2c06712] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Mechanochromophores based on conformational changes of donor-acceptor-donor (DAD) springs allow sensing of forces acting on polymer chains by monotonic changes of absorbance or photoluminescence (PL) wavelength. Here, we identify a series of thiophene (D)-flanked quinoxalines (A) as molecular torsional springs for force sensing in bulk polymers at room temperature. The mode of DAD linkage to the polymer matrix and linker rigidity are key parameters that influence the efficacy of force transduction to the DAD spring and thus mechanochromic response, as probed by in situ PL spectroscopy of bulk films during stress-strain experiments. The largest shift of the PL maximum, and thus the highest sensitivity, is obtained from an ansa-DAD spring exhibiting bridged D units and a stiff A linker. Using detailed spectroscopy and density functional theory calculations, we reveal conformer redistribution in the form of a thiophene ring flip as the major part of the overall mechanochromic response. At forces as low as 27 pN at early stages of deformation, the ring flip precedes mechanically induced planarization of the ansa-DAD spring, the latter process producing a PL shift of 21 nm nN-1. Within the stress-strain diagram, the thiophene ring flip and DAD planarization are thus two separated processes that also cause irreversible and reversible mechanochromic responses, respectively, upon sample failure. As the thiophene ring flip requires much smaller forces than planarization of the DAD spring, such micromechanical motion gives access to sensing of tiny forces and expands both sensitivity and the force range of conformational mechanochromophores.
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Affiliation(s)
- Raphael Hertel
- Institute for Chemistry, Chemnitz University of Technology, Chemnitz09111, Germany
| | - Wafa Maftuhin
- FIT Freiburg Centre for Interactive Materials and Bioinspired Technologies, University of Freiburg, Freiburg79110, Germany.,Cluster of Excellence livMatS @ FIT, Freiburg79110, Germany
| | - Michael Walter
- FIT Freiburg Centre for Interactive Materials and Bioinspired Technologies, University of Freiburg, Freiburg79110, Germany.,Cluster of Excellence livMatS @ FIT, Freiburg79110, Germany.,Fraunhofer IWM, MikroTribologie Centrum μTC, Freiburg79108, Germany
| | - Michael Sommer
- Institute for Chemistry, Chemnitz University of Technology, Chemnitz09111, Germany
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29
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Sun C, Zhang S, Ren Y, Zhang J, Shen J, Qin S, Hu W, Zhu S, Yang H, Yang D. Force-Induced Synergetic Pigmentary and Structural Color Change of Liquid Crystalline Elastomer with Nanoparticle-Enhanced Mechanosensitivity. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2205325. [PMID: 36310104 PMCID: PMC9798961 DOI: 10.1002/advs.202205325] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 10/08/2022] [Indexed: 06/04/2023]
Abstract
The ability of some animals to rapidly change their colors can greatly improve their chances of escaping predators or hunting prey. A classic example is cephalopods, which can rapidly shift through a wide range of colors. This ability is based on the synergetic effect of the change of pigmentary and structural colors exhibited by their own two categories of color-changing cells: supernatant chromatophores offer various pigmentary colors and lower iridophores or leucophores reflect the different structural colors by adjusting their periodicities. Here, a mechanochromic liquid crystalline elastomer with force-induced synergetic pigmentary and structural color change, whose mechanosensitivity is enhanced by the stress-concentration induced by the doped nanoparticle, is presented. The materials have a large color-changing gamut and high mechanochromic sensitivity, which exhibit great potential in the field of mechanical detectors, sensors, and anti-counterfeiting materials.
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Affiliation(s)
- Chang Sun
- University of Science and Technology BeijingNo. 30 Xueyuan Road, Haidian DistrictBeijing100083China
| | - Shuoning Zhang
- Peking UniversityNo. 5 Yiheyuan Road Haidian DistrictBeijing100871P. R. China
| | - YunXiao Ren
- University of Science and Technology BeijingNo. 30 Xueyuan Road, Haidian DistrictBeijing100083China
| | - Jianying Zhang
- University of Science and Technology BeijingNo. 30 Xueyuan Road, Haidian DistrictBeijing100083China
| | - Jiyuan Shen
- University of Science and Technology BeijingNo. 30 Xueyuan Road, Haidian DistrictBeijing100083China
| | - Shengyu Qin
- Peking UniversityNo. 5 Yiheyuan Road Haidian DistrictBeijing100871P. R. China
| | - Wei Hu
- University of Science and Technology BeijingNo. 30 Xueyuan Road, Haidian DistrictBeijing100083China
| | - Siquan Zhu
- Department of OphthalmologyBeijing Anzhen HospitalCapital Medical UniversityBeijing100029P. R. China
| | - Huai Yang
- Peking UniversityNo. 5 Yiheyuan Road Haidian DistrictBeijing100871P. R. China
| | - Dengke Yang
- Kent State University1425 Lefton EsplanadeKentOH44242USA
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30
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Luo SM, Barber RW, Overholts AC, Robb MJ. Competitive Activation Experiments Reveal Significantly Different Mechanochemical Reactivity of Furan–Maleimide and Anthracene–Maleimide Mechanophores. ACS POLYMERS AU 2022; 3:202-208. [PMID: 37065719 PMCID: PMC10103189 DOI: 10.1021/acspolymersau.2c00047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 11/01/2022] [Accepted: 11/01/2022] [Indexed: 11/23/2022]
Abstract
During the past two decades, our understanding of mechanochemical reactivity has advanced considerably. Nevertheless, an incomplete knowledge of structure-activity relationships and the principles that govern mechanochemical transformations limits molecular design. The experimental development of mechanophores has thus benefited from simple computational tools like CoGEF, from which quantitative metrics like rupture force can be extracted to estimate reactivity. Furan-maleimide (FM) and anthracene-maleimide (AM) Diels-Alder adducts are widely studied mechanophores that undergo retro-Diels-Alder reactions upon mechanical activation in polymers. Despite possessing significantly different thermal stability, similar rupture forces predicted by CoGEF calculations suggest that these compounds exhibit similar mechanochemical reactivity. Here, we directly probe the relative mechanochemical reactivity of FM and AM adducts through competitive activation experiments. Ultrasound-induced mechanochemical activation of bis-adduct mechanophores comprising covalently tethered FM and AM subunits reveals pronounced selectivity-as high as ∼13:1-for reaction of the FM adduct compared to the AM adduct. Computational models provide insight into the greater reactivity of the FM mechanophore, indicating a more efficient mechanochemical coupling for the FM adduct compared to the AM adduct. The methodology employed here to directly interrogate the relative reactivity of two different mechanophores using a tethered bis-adduct configuration may be useful for other systems where more common sonication-based approaches are limited by poor sensitivity.
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Affiliation(s)
- Stella M. Luo
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Ross W. Barber
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Anna C. Overholts
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Maxwell J. Robb
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
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31
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Khodayeki S, Maftuhin W, Walter M. Force Dependent Barriers from Analytic Potentials within Elastic Environments. Chemphyschem 2022; 23:e202200237. [PMID: 35703590 DOI: 10.1002/cphc.202200237] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 06/14/2022] [Indexed: 01/07/2023]
Abstract
Bond rupture under the action of external forces is usually induced by temperature fluctuations, where the key quantity is the force dependent barrier that needs to be overcome. Using analytic potentials we find that these barriers are fully determined by the dissociation energy and the maximal force the potential can withstand. The barrier shows a simple dependence on these two quantities that allows for a re-interpretation of the Eyring-Zhurkov-Bell length Δ x ‡ and the expressions in theories going beyond that. It is shown that solely elastic environments do not change this barrier in contrast to the predictions of constraint geometry simulate external force (COGEF) strategies. The findings are confirmed by explicit calculations of bond rupture in a polydimethylsiloxane model.
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Affiliation(s)
- Samaneh Khodayeki
- Freiburger Institut für Interaktive Materialien und Bioinspirierte Technologien, Georges-Köhler-Allee 105, 79110, Freiburg, Germany
- Physikalisches Institut, Universität Freiburg, Herrmann-Herder-Straße 3, 79104, Freiburg, Germany
| | - Wafa Maftuhin
- Freiburger Institut für Interaktive Materialien und Bioinspirierte Technologien, Georges-Köhler-Allee 105, 79110, Freiburg, Germany
- Physikalisches Institut, Universität Freiburg, Herrmann-Herder-Straße 3, 79104, Freiburg, Germany
| | - Michael Walter
- Freiburger Institut für Interaktive Materialien und Bioinspirierte Technologien, Georges-Köhler-Allee 105, 79110, Freiburg, Germany
- Physikalisches Institut, Universität Freiburg, Herrmann-Herder-Straße 3, 79104, Freiburg, Germany
- Cluster of Excellence livMatS@FIT, Freiburg, Germany
- Fraunhofer Institut für Werkstoffmechanik, Wöhlerstraße 11, 79108, Freiburg, Germany
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32
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Hsu CC, Hsia FC, Weber B, de Rooij MB, Bonn D, Brouwer AM. Local Shearing Force Measurement during Frictional Sliding Using Fluorogenic Mechanophores. J Phys Chem Lett 2022; 13:8840-8844. [PMID: 36112048 PMCID: PMC9531245 DOI: 10.1021/acs.jpclett.2c02010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 09/13/2022] [Indexed: 06/15/2023]
Abstract
When two macroscopic objects touch, the real contact typically consists of multiple surface asperities that are deformed under the pressure that holds the objects together. Application of a shear force makes the objects slide along each other, breaking the initial contacts. To investigate how the microscopic shear force at the asperity level evolves during the transition from static to dynamic friction, we apply a fluorogenic mechanophore to visualize and quantify the local interfacial shear force. When a contact is broken, the shear force is released and the molecules return to their dark state, allowing us to dynamically observe the evolution of the shear force at the sliding contacts. We find that the macroscopic coefficient of friction describes the microscopic friction well, and that slip propagates from the edge toward the center of the macroscopic contact area before sliding occurs. This allows for a local understanding of how surfaces start to slide.
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Affiliation(s)
- Chao-Chun Hsu
- van’t
Hoff Institute for Molecular Sciences, University
of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Feng-Chun Hsia
- Advanced
Research Center for Nanolithography, Science Park 106, 1098 XG Amsterdam, The Netherlands
- van
der Waals-Zeeman Institute, Institute of Physics, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Bart Weber
- Advanced
Research Center for Nanolithography, Science Park 106, 1098 XG Amsterdam, The Netherlands
- van
der Waals-Zeeman Institute, Institute of Physics, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Matthijn B. de Rooij
- Laboratory
for Surface Technology and Tribology, Department of Engineering Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Daniel Bonn
- van
der Waals-Zeeman Institute, Institute of Physics, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Albert M. Brouwer
- van’t
Hoff Institute for Molecular Sciences, University
of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
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33
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Wu M, Li Y, Yuan W, De Bo G, Cao Y, Chen Y. Cooperative and Geometry-Dependent Mechanochromic Reactivity through Aromatic Fusion of Two Rhodamines in Polymers. J Am Chem Soc 2022; 144:17120-17128. [PMID: 36070612 DOI: 10.1021/jacs.2c07015] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The unique topological features of Piezo proteins underlie the lever-like cellular mechanotransduction mechanism. This knowledge inspires us to seek topological/geometric control of mechanochromophores with unprecedentedly amplified, synergistic changes in polymers to serve as ideal stress probes. Here, by judicious placement of two spirolactam rings into aminobenzopyranoxanthene, a series of stereo- and regio-isomeric rhodamine-like mechanophores are developed. With two labile bonds closely coupled into one rigidified scaffold, these π-fused bis-mechanophores enable mechanochromic polymers, featuring cooperative bond scission, low rupture force (lower than rhodamine), and geometry-controlled ring-opening reactivity. Sonication, single-molecule force spectroscopy experiments, and density functional theory calculations provide insight into the force-color relationship and rationalize how the difference in reactivity of the four isomeric mechanophores is affected by their molecular geometry and thermodynamic equilibrium. Our strategy based on the aromatic fusion of bis-mechanophore promises a modular approach to isomeric mechanophores for cooperative bond scission. Also, important insights into internal and external factors governing tandem mechanochemical reactions are gained.
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Affiliation(s)
- Mengjiao Wu
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, P. R. China.,Department of Chemistry, Tianjin University, Tianjin 300354, P. R. China
| | - Yiran Li
- Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid State Microstructure, Department of Physics, Nanjing University, Nanjing 210093, P. R. China
| | - Wei Yuan
- Department of Chemistry, Tianjin University, Tianjin 300354, P. R. China
| | - Guillaume De Bo
- Department of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Yi Cao
- Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid State Microstructure, Department of Physics, Nanjing University, Nanjing 210093, P. R. China
| | - Yulan Chen
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, P. R. China
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34
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Baumann C, Willis‐Fox N, Campagna D, Rognin E, Marten P, Daly R, Göstl R. Regiochemical effects for the mechanochemical activation of
9‐π‐extended anthracene‐maleimide Diels–Alder
adducts. JOURNAL OF POLYMER SCIENCE 2022. [DOI: 10.1002/pol.20220342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Christoph Baumann
- DWI – Leibniz Institute for Interactive Materials Aachen Germany
- Institute of Technical and Macromolecular Chemistry, RWTH Aachen University Aachen Germany
| | - Niamh Willis‐Fox
- Department of Engineering, Institute for Manufacturing University of Cambridge Cambridge UK
| | - Davide Campagna
- DWI – Leibniz Institute for Interactive Materials Aachen Germany
- Institute of Technical and Macromolecular Chemistry, RWTH Aachen University Aachen Germany
| | - Etienne Rognin
- Department of Engineering, Institute for Manufacturing University of Cambridge Cambridge UK
| | - Paul Marten
- DWI – Leibniz Institute for Interactive Materials Aachen Germany
- Institute of Technical and Macromolecular Chemistry, RWTH Aachen University Aachen Germany
| | - Ronan Daly
- Department of Engineering, Institute for Manufacturing University of Cambridge Cambridge UK
| | - Robert Göstl
- DWI – Leibniz Institute for Interactive Materials Aachen Germany
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35
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Qiu W, Scofield JMP, Gurr PA, Qiao GG. Mechanochromophore-linked Polymeric Materials with Visible Color Changes. Macromol Rapid Commun 2022; 43:e2100866. [PMID: 35338794 DOI: 10.1002/marc.202100866] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 03/19/2022] [Indexed: 11/07/2022]
Abstract
Mechanical force as a type of stimuli for smart materials has obtained much attention in the past decade. Color-changing materials in response to mechanical stimuli have shown great potential in the applications such as sensors and displays. Mechanochromophore-linked polymeric materials, which are a growing sub-class of these materials, are discussed in detail in this review. Two main types of mechanochromophores which exhibit visible color change, summarized herein, involve either isomerization or radical generation mechanisms. This review focuses on their synthesis and incorporation into polymer matrices, the type of mechanical force used, factors affecting the mechanochromic properties, and their applications. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Wenlian Qiu
- Department of Chemical Engineering, The University of Melbourne, Parkville, Victoria, 3010, Australia
| | - Joel M P Scofield
- Department of Chemical Engineering, The University of Melbourne, Parkville, Victoria, 3010, Australia
| | - Paul A Gurr
- Department of Chemical Engineering, The University of Melbourne, Parkville, Victoria, 3010, Australia
| | - Greg G Qiao
- Department of Chemical Engineering, The University of Melbourne, Parkville, Victoria, 3010, Australia
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36
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Küng R, Göstl R, Schmidt BM. Release of Molecular Cargo from Polymer Systems by Mechanochemistry. Chemistry 2022; 28:e202103860. [PMID: 34878679 PMCID: PMC9306765 DOI: 10.1002/chem.202103860] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Indexed: 11/15/2022]
Abstract
The design and manipulation of (multi)functional materials at the nanoscale holds the promise of fuelling tomorrow's major technological advances. In the realm of macromolecular nanosystems, the incorporation of force-responsive groups, so called mechanophores, has resulted in unprecedented access to responsive behaviours and enabled sophisticated functions of the resulting structures and advanced materials. Among the diverse force-activated motifs, the on-demand release or activation of compounds, such as catalysts, drugs, or monomers for self-healing, are sought-after since they enable triggering pristine small molecule function from macromolecular frameworks. Here, we highlight examples of molecular cargo release systems from polymer-based architectures in solution by means of sonochemical activation by ultrasound (ultrasound-induced mechanochemistry). Important design concepts of these advanced materials are discussed, as well as their syntheses and applications.
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Affiliation(s)
- Robin Küng
- Institut für Organische Chemie und Makromolekulare ChemieHeinrich-Heine-Universität DüsseldorfUniversitätsstraße 140225DüsseldorfGermany
| | - Robert Göstl
- DWI – Leibniz Institute for Interactive MaterialsForckenbeckstr. 5052056AachenGermany
| | - Bernd M. Schmidt
- Institut für Organische Chemie und Makromolekulare ChemieHeinrich-Heine-Universität DüsseldorfUniversitätsstraße 140225DüsseldorfGermany
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37
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Yamakado T, Saito S. Ratiometric Flapping Force Probe That Works in Polymer Gels. J Am Chem Soc 2022; 144:2804-2815. [PMID: 35108003 DOI: 10.1021/jacs.1c12955] [Citation(s) in RCA: 40] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Polymer gels have recently attracted attention for their application in flexible devices, where mechanically robust gels are required. While there are many strategies to produce tough gels by suppressing nanoscale stress concentration on specific polymer chains, it is still challenging to directly verify the toughening mechanism at the molecular level. To solve this problem, the use of the flapping molecular force probe (FLAP) is promising because it can evaluate the nanoscale forces transmitted in the polymer chain network by ratiometric analysis of a stress-dependent dual fluorescence. A flexible conformational change of FLAP enables real-time and reversible responses to the nanoscale forces at the low force threshold, which is suitable for quantifying the percentage of the stressed polymer chains before structural damage. However, the previously reported FLAP only showed a negligible response in solvated environments because undesirable spontaneous planarization occurs in the excited state, even without mechanical force. Here, we have developed a new ratiometric force probe that functions in common organogels. Replacement of the anthraceneimide units in the flapping wings with pyreneimide units largely suppresses the excited-state planarization, leading to the force probe function under wet conditions. The FLAP-doped polyurethane organogel reversibly shows a dual-fluorescence response under sub-MPa compression. Moreover, the structurally modified FLAP is also advantageous in the wide dynamic range of its fluorescence response in solvent-free elastomers, enabling clearer ratiometric fluorescence imaging of the molecular-level stress concentration during crack growth in a stretched polyurethane film.
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Affiliation(s)
- Takuya Yamakado
- Graduate School of Science, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan
| | - Shohei Saito
- Graduate School of Science, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan
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38
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van Galen M, Kaniraj JP, Albada B, Sprakel J. Single-Molecule Force Spectroscopy of a Tetraaryl Succinonitrile Mechanophore. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2022; 126:1215-1221. [PMID: 35087610 PMCID: PMC8785187 DOI: 10.1021/acs.jpcc.1c09314] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 12/21/2021] [Indexed: 06/14/2023]
Abstract
Fluorescent damage reporters that use mechanochemical activation of a covalent bond to elicit an optical signal are emerging tools in material mechanics as a means to access the nanoscale distribution of forces inside materials under stress. A promising class of damage reporters are tetraaryl succinonitriles (TASN), whose mechanical activation results in stable fluorescent radical species. However, in-depth insights into the molecular mechanics of TASN activation are absent, precluding their use as quantitative mechanoprobes. Here we perform single-molecule force spectroscopy experiments to provide these insights. We use a bridged version of the TASN unit, embedded in multi-mechanophore polymer, to enable multiplexed mechanochemical measurements at the single-molecule level. Our experiments reveal that TASN activates at surprisingly low forces and short time scales compared to other covalent mechanophores. These results establish TASN as a promising candidate for reporting the lower end of relevant forces in material mechanics.
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Affiliation(s)
- Martijn van Galen
- Physical
Chemistry and Soft Matter, Wageningen University
& Research, Stippeneng 4, 6708WE Wageningen, The Netherlands
| | - Jeya Prathap Kaniraj
- Physical
Chemistry and Soft Matter, Wageningen University
& Research, Stippeneng 4, 6708WE Wageningen, The Netherlands
- Laboratory
of Organic Chemistry, Wageningen University
& Research, Stippeneng 4, 6708WE Wageningen, The Netherlands
| | - Bauke Albada
- Laboratory
of Organic Chemistry, Wageningen University
& Research, Stippeneng 4, 6708WE Wageningen, The Netherlands
| | - Joris Sprakel
- Physical
Chemistry and Soft Matter, Wageningen University
& Research, Stippeneng 4, 6708WE Wageningen, The Netherlands
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39
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Kotani R, Yokoyama S, Nobusue S, Yamaguchi S, Osuka A, Yabu H, Saito S. Bridging pico-to-nanonewtons with a ratiometric force probe for monitoring nanoscale polymer physics before damage. Nat Commun 2022; 13:303. [PMID: 35027559 PMCID: PMC8758707 DOI: 10.1038/s41467-022-27972-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 12/15/2021] [Indexed: 02/07/2023] Open
Abstract
Understanding the transmission of nanoscale forces in the pico-to-nanonewton range is important in polymer physics. While physical approaches have limitations in analyzing the local force distribution in condensed environments, chemical analysis using force probes is promising. However, there are stringent requirements for probing the local forces generated before structural damage. The magnitude of those forces corresponds to the range below covalent bond scission (from 200 pN to several nN) and above thermal fluctuation (several pN). Here, we report a conformationally flexible dual-fluorescence force probe with a theoretically estimated threshold of approximately 100 pN. This probe enables ratiometric analysis of the distribution of local forces in a stretched polymer chain network. Without changing the intrinsic properties of the polymer, the force distribution was reversibly monitored in real time. Chemical control of the probe location demonstrated that the local stress concentration is twice as biased at crosslinkers than at main chains, particularly in a strain-hardening region. Due to the high sensitivity, the percentage of the stressed force probes was estimated to be more than 1000 times higher than the activation rate of a conventional mechanophore.
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Affiliation(s)
- Ryota Kotani
- Graduate School of Science, Kyoto University, Kyoto, 606-8502, Japan
| | - Soichi Yokoyama
- Graduate School of Science, Kyoto University, Kyoto, 606-8502, Japan
| | - Shunpei Nobusue
- Institute of Advanced Energy, Kyoto University, Uji, 611-0011, Japan
| | | | - Atsuhiro Osuka
- Graduate School of Science, Kyoto University, Kyoto, 606-8502, Japan
| | - Hiroshi Yabu
- WPI-Advanced Institute for Materials Research (AIMR), Tohoku University, Sendai, 980-8577, Japan.
| | - Shohei Saito
- Graduate School of Science, Kyoto University, Kyoto, 606-8502, Japan.
- PRESTO, Japan Science and Technology Agency, Kyoto, 606-8502, Japan.
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40
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Versaw BA, Zeng T, Hu X, Robb MJ. Harnessing the Power of Force: Development of Mechanophores for Molecular Release. J Am Chem Soc 2021; 143:21461-21473. [PMID: 34927426 DOI: 10.1021/jacs.1c11868] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Polymers that release small molecules in response to mechanical force are promising materials for a variety of applications ranging from sensing and catalysis to targeted drug delivery. Within the rapidly growing field of polymer mechanochemistry, stress-sensitive molecules known as mechanophores are particularly attractive for enabling the release of covalently bound payloads with excellent selectivity and control. Here, we review recent progress in the development of mechanophore-based molecular release platforms and provide an optimistic, yet critical perspective on the fundamental and technological advancements that are still required for this promising research area to achieve significant impact.
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Affiliation(s)
- Brooke A Versaw
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Tian Zeng
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Xiaoran Hu
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Maxwell J Robb
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
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41
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Overholts AC, McFadden ME, Robb MJ. Quantifying Activation Rates of Scissile Mechanophores and the Influence of Dispersity. Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c02232] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Anna C. Overholts
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Molly E. McFadden
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Maxwell J. Robb
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
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42
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Wang QF, Fan HC, Zhou Q, Chen X, Wang LJ, Lu ZX, Yang SX, Zheng LY, Cao QE. Reversible Photochromic Coordination Polymer by Phototriggered Subtle Molecular Conformation Variations. Inorg Chem 2021; 60:18870-18878. [PMID: 34855375 DOI: 10.1021/acs.inorgchem.1c02657] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Photochromic materials are constructed with molecules accompanied by structural change after triggering by light, which are of great importance and necessity for various applications. However, because of space-confinement effects, molecule stacking of these photoresponsive chromophores within coordination polymers (CPs) always results in an efficiency decrement and a response delay, and this phenomenon will lead to a poor photochromic property. Herein, a CP (named CIT-E) with a 3-fold-interpenetrating network structure, which was prepared with (Z)-1,2-diphenyl-1,2-bis[4-(pyridin-3-ylmethoxy)phenyl]ethene (1Z) and a CuI cluster, showed fast reversible photochromic behavior. Under UV-light illumination, the color of CIT-Z changed from pale yellow to reddish brown. With the illumination of green light, the polymer could return to its initial color within 10 s. To reveal the mechanism of reversible photochromic behavior of CIT-Z, single-crystal structures of each color state were fully studied, and other scientific study methods were also used, such as time-dependent density functional theory calculation and control experiments. It was found that, with light illumination, this behavior of CIT-Z was the result of a ligand-to-metal charge-transfer process, and this process was triggered by subtle molecular conformation variation of tetraphenylethylene. It should be noted that CIT-Z has high thermal and chemical stability, which are excellent advantages as smart photoresponsive materials. As a proof of concept, a uniform thin film with such a fascinating photochromic property allows applications in invisible anticounterfeiting and dynamic optical data storage. Overall, the present study opens up a new avenue toward reversible photochromic materials.
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Affiliation(s)
- Qiu-Feng Wang
- Key Laboratory of Medicinal Chemistry for Natural Resource of Yunnan University, Ministry of Education, Functional Molecules Analysis and Biotransformation Key Laboratory of Universities in Yunnan Province, School of Chemical Science and Technology, Yunnan University, Kunming 650091, People's Republic of China
| | - Hong-Chuan Fan
- Key Laboratory of Medicinal Chemistry for Natural Resource of Yunnan University, Ministry of Education, Functional Molecules Analysis and Biotransformation Key Laboratory of Universities in Yunnan Province, School of Chemical Science and Technology, Yunnan University, Kunming 650091, People's Republic of China
| | - Qian Zhou
- Key Laboratory of Medicinal Chemistry for Natural Resource of Yunnan University, Ministry of Education, Functional Molecules Analysis and Biotransformation Key Laboratory of Universities in Yunnan Province, School of Chemical Science and Technology, Yunnan University, Kunming 650091, People's Republic of China
| | - Xin Chen
- Key Laboratory of Medicinal Chemistry for Natural Resource of Yunnan University, Ministry of Education, Functional Molecules Analysis and Biotransformation Key Laboratory of Universities in Yunnan Province, School of Chemical Science and Technology, Yunnan University, Kunming 650091, People's Republic of China
| | - Long-Jie Wang
- Key Laboratory of Medicinal Chemistry for Natural Resource of Yunnan University, Ministry of Education, Functional Molecules Analysis and Biotransformation Key Laboratory of Universities in Yunnan Province, School of Chemical Science and Technology, Yunnan University, Kunming 650091, People's Republic of China
| | - Zhi-Xiang Lu
- Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, Center for Molecular Imaging and Translational Medicine, School of Public Health, Xiamen University, Xiamen 361102, People's Republic of China
| | - Shao-Xiong Yang
- Key Laboratory of Medicinal Chemistry for Natural Resource of Yunnan University, Ministry of Education, Functional Molecules Analysis and Biotransformation Key Laboratory of Universities in Yunnan Province, School of Chemical Science and Technology, Yunnan University, Kunming 650091, People's Republic of China
| | - Li-Yan Zheng
- Key Laboratory of Medicinal Chemistry for Natural Resource of Yunnan University, Ministry of Education, Functional Molecules Analysis and Biotransformation Key Laboratory of Universities in Yunnan Province, School of Chemical Science and Technology, Yunnan University, Kunming 650091, People's Republic of China
| | - Qiu-E Cao
- Key Laboratory of Medicinal Chemistry for Natural Resource of Yunnan University, Ministry of Education, Functional Molecules Analysis and Biotransformation Key Laboratory of Universities in Yunnan Province, School of Chemical Science and Technology, Yunnan University, Kunming 650091, People's Republic of China
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43
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Abstract
AbstractThis Account covers the recent progress made on heterocyclic mechanophores in the field of polymer mechanochemistry. In particular, the types of such mechanophores as well as the mechanisms and applications of their force-induced structural transformations are discussed and related perspectives and future challenges proposed.1 Introduction2 Types of Mechanophores3 Methods to Incorporate Heterocycle Mechanophores into Polymer Systems4 Mechanochemical Reactions of Heterocyclic Mechanophores4.1 Three-Membered-Ring Mechanophores4.2 Four-Membered-Ring Mechanophores4.3 Six-Membered-Ring Mechanophores4.4 Bicyclic Mechanophores5 Applications5.1 Cross-Linking of Polymer5.2 Degradable Polymer5.3 Mechanochromic Polymer6 Concluding Remarks and Outlook
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44
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He S, Stratigaki M, Centeno SP, Dreuw A, Göstl R. Tailoring the Properties of Optical Force Probes for Polymer Mechanochemistry. Chemistry 2021; 27:15889-15897. [PMID: 34582082 PMCID: PMC9292383 DOI: 10.1002/chem.202102938] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Indexed: 02/05/2023]
Abstract
The correlation of mechanical properties of polymer materials with those of their molecular constituents is the foundation for their holistic comprehension and eventually for improved material designs and syntheses. Over the last decade, optical force probes (OFPs) were developed, shedding light on various unique mechanical behaviors of materials. The properties of polymers are diverse, ranging from soft hydrogels to ultra-tough composites, from purely elastic rubbers to viscous colloidal solutions, and from transparent glasses to super black dyed coatings. Only very recently, researchers started to develop tailored OFP solutions that account for such material requirements in energy (both light and force), in time, and in their spatially detectable resolution. We here highlight notable recent examples and identify future challenges in this emergent field.
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Affiliation(s)
- Siyang He
- DWI - Leibniz Institute for Interactive MaterialsForckenbeckstr. 5052056AachenGermany
- Institute of Technical and Macromolecular ChemistryRWTH Aachen UniversityWorringerweg 152074AachenGermany
| | - Maria Stratigaki
- DWI - Leibniz Institute for Interactive MaterialsForckenbeckstr. 5052056AachenGermany
| | - Silvia P. Centeno
- DWI - Leibniz Institute for Interactive MaterialsForckenbeckstr. 5052056AachenGermany
| | - Andreas Dreuw
- Interdisciplinary Center for Scientific ComputingHeidelberg UniversityIm Neuenheimer Feld 20569120HeidelbergGermany
| | - Robert Göstl
- DWI - Leibniz Institute for Interactive MaterialsForckenbeckstr. 5052056AachenGermany
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45
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Chen Y, Sanoja G, Creton C. Mechanochemistry unveils stress transfer during sacrificial bond fracture of tough multiple network elastomers. Chem Sci 2021; 12:11098-11108. [PMID: 34522307 PMCID: PMC8386638 DOI: 10.1039/d1sc03352b] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 07/02/2021] [Indexed: 01/05/2023] Open
Abstract
The molecular level transfer of stress from a stiff percolating filler to a stretchable matrix is a crucial and generic mechanism of toughening in soft materials. Yet the molecular details of how this transfer occurs have so far been experimentally unreachable. Model multiple network elastomers containing spiropyran (SP) force sensors incorporated into the stiff filler network or into the stretchable matrix network are used here to detect and investigate the mechanism of stress transfer between distinct populations of polymer strands. We find that as the filler network progressively breaks by random bond scission, there is a critical stress where cooperative bond scission occurs and the macroscopic stretch increases discontinuously by necking. Surprisingly, SP molecules reveal that even in the necked region both filler and matrix chains share the load, with roughly 90% of the SPs force-activated in the filler chains before necking still being loaded in the necked region where significant activation of the SP incorporated into the matrix chains occurs. This result, where both networks remain loaded upon necking, is qualitatively consistent with the model proposed by Brown, where holes or microcracks are formed in the stiff regions and are bridged by stretched matrix chains. Detection of merocyanine (i.e. activated SP) fluorescence by confocal microscopy shows that such microcrack formation is also active at the crack tip even for materials that do not exhibit macroscopic necking. Additionally, we demonstrate that when the ethyl acrylate monomer is replaced by hexyl methacrylate in the first network, preventing molecular connections between the two networks, the stress transmission is less efficient. This study outlines the different roles played by these multiple networks in the onset of fracture and provides molecular insights for the construction of molecular models of fracture of elastomers.
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Affiliation(s)
- Yinjun Chen
- Laboratoire Sciences et Ingénierie de la Matière Molle, ESPCI Paris, PSL University, Sorbonne Université, CNRS F-75005 Paris France
| | - Gabriel Sanoja
- Laboratoire Sciences et Ingénierie de la Matière Molle, ESPCI Paris, PSL University, Sorbonne Université, CNRS F-75005 Paris France
| | - Costantino Creton
- Laboratoire Sciences et Ingénierie de la Matière Molle, ESPCI Paris, PSL University, Sorbonne Université, CNRS F-75005 Paris France
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46
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Horst M, Yang J, Meisner J, Kouznetsova TB, Martínez TJ, Craig SL, Xia Y. Understanding the Mechanochemistry of Ladder-Type Cyclobutane Mechanophores by Single Molecule Force Spectroscopy. J Am Chem Soc 2021; 143:12328-12334. [PMID: 34310875 DOI: 10.1021/jacs.1c05857] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We have recently reported a series of ladder-type cyclobutane mechanophores, polymers of which can transform from nonconjugated structures to conjugated structures and change many properties at once. These multicyclic mechanophores, namely, exo-ladderane/ene, endo-benzoladderene, and exo-bicyclohexene-peri-naphthalene, have different ring structures fused to the first cyclobutane, significantly different free energy changes for ring-opening, and different stereochemistry. To better understand their mechanochemistry, we used single molecule force spectroscopy (SMFS) to characterize their force-extension behavior and measure the threshold forces. The threshold forces correlate with the activation energy of the first bond, but not with the strain of the fused rings distal to the polymer main chain, suggesting that the activation of these ladder-type mechanophores occurs with similar early transition states, which is supported by force-modified potential energy surface calculations. We further determined the stereochemistry of the mechanically generated dienes and observed significant and variable contour length elongation for these mechanophores both experimentally and computationally. The fundamental understanding of ladder-type mechanophores will facilitate future design of multicyclic mechanophores with amplified force-response and their applications as mechanically responsive materials.
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Affiliation(s)
- Matías Horst
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Jinghui Yang
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Jan Meisner
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Tatiana B Kouznetsova
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Todd J Martínez
- Department of Chemistry, Stanford University, Stanford, California 94305, United States.,SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Stephen L Craig
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Yan Xia
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
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47
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Giordano G, Gagliardi M, Huan Y, Carlotti M, Mariani A, Menciassi A, Sinibaldi E, Mazzolai B. Toward Mechanochromic Soft Material-Based Visual Feedback for Electronics-Free Surgical Effectors. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:e2100418. [PMID: 34075732 PMCID: PMC8336492 DOI: 10.1002/advs.202100418] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 04/21/2021] [Indexed: 05/07/2023]
Abstract
A chromogenically reversible, mechanochromic pressure sensor is integrated into a mininvasive surgical grasper compatible with the da Vinci robotic surgical system. The sensorized effector, also featuring two soft-material jaws, encompasses a mechanochromic polymeric inset doped with functionalized spiropyran (SP) molecule, designed to activate mechanochromism at a chosen pressure and providing a reversible color change. Considering such tools are systematically in the visual field of the operator during surgery, color change of the mechanochromic effector can help avoid tissue damage. No electronics is required to control the devised visual feedback. SP-doping of polydimethylsiloxane (2.5:1 prepolymer/curing agent weight ratio) permits to modulate the mechanochromic activation pressure, with lower values around 1.17 MPa for a 2% wt. SP concentration, leading to a shorter chromogenic recovery time of 150 s at room temperature (25 °C) under green light illumination. Nearly three-times shorter recovery time is observed at body temperature (37 °C). To the best of knowledge, this study provides the first demonstration of mechanochromic materials in surgery, in particular to sensorize unpowered surgical effectors, by avoiding dramatic increases in tool complexity due to additional electronics, thus fostering their application. The proposed sensing strategy can be extended to further tools and scopes.
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Affiliation(s)
- Goffredo Giordano
- Center for Micro‐BioRoboticsItalian Institute of TechnologyViale Rinaldo Piaggio 34Pontedera (PI)56025Italy
- The BioRobotics InstituteScuola Superiore Sant'AnnaViale Rinaldo Piaggio 34Pontedera (PI)56025Italy
- Department of Excellence in Robotics and AIScuola Superiore Sant'AnnaPiazza Martiri della Libertà 33Pisa (PI)56127Italy
| | - Mariacristina Gagliardi
- NESTScuola Normale Superiore and Istituto NanoscienzeConsiglio Nazionale delle RicerchePiazza S. Silvestro, 12Pisa (PI)56127Italy
| | - Yu Huan
- The BioRobotics InstituteScuola Superiore Sant'AnnaViale Rinaldo Piaggio 34Pontedera (PI)56025Italy
- Department of Excellence in Robotics and AIScuola Superiore Sant'AnnaPiazza Martiri della Libertà 33Pisa (PI)56127Italy
| | - Marco Carlotti
- Center for Micro‐BioRoboticsItalian Institute of TechnologyViale Rinaldo Piaggio 34Pontedera (PI)56025Italy
| | - Andrea Mariani
- The BioRobotics InstituteScuola Superiore Sant'AnnaViale Rinaldo Piaggio 34Pontedera (PI)56025Italy
- Department of Excellence in Robotics and AIScuola Superiore Sant'AnnaPiazza Martiri della Libertà 33Pisa (PI)56127Italy
| | - Arianna Menciassi
- The BioRobotics InstituteScuola Superiore Sant'AnnaViale Rinaldo Piaggio 34Pontedera (PI)56025Italy
- Department of Excellence in Robotics and AIScuola Superiore Sant'AnnaPiazza Martiri della Libertà 33Pisa (PI)56127Italy
| | - Edoardo Sinibaldi
- Center for Micro‐BioRoboticsItalian Institute of TechnologyViale Rinaldo Piaggio 34Pontedera (PI)56025Italy
| | - Barbara Mazzolai
- Center for Micro‐BioRoboticsItalian Institute of TechnologyViale Rinaldo Piaggio 34Pontedera (PI)56025Italy
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48
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Muramatsu T, Okado Y, Traeger H, Schrettl S, Tamaoki N, Weder C, Sagara Y. Rotaxane-Based Dual Function Mechanophores Exhibiting Reversible and Irreversible Responses. J Am Chem Soc 2021; 143:9884-9892. [PMID: 34162206 DOI: 10.1021/jacs.1c03790] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Mechanochromic mechanophores permit the design of polymers that indicate mechanical events through optical signals. Here we report rotaxane-based supramolecular mechanophores that display both reversible and irreversible fluorescence changes. These responses are triggered by different forces and are achieved by exploiting the molecular shuttling function and force-induced dethreading of rotaxanes. The new rotaxane mechanophores are composed of a ring featuring a luminophore, which is threaded onto an axle with a matching quencher and two stoppers. In the stress-free state, the luminophore is preferentially located in the proximity of the quencher, and the emission is quenched. The luminophore slides away from the quencher when a force is applied and the fluorescence is switched on. This effect is reversible, unless the force is so high that the luminophore-carrying ring slips past the stopper and dethreading occurs. We show that the combination of judiciously selected ring and stopper moieties is crucial to attain interlocked structures that display such a dual response. PU elastomers that contain such doubly responsive rotaxanes exhibit reversible fluorescence changes over multiple loading-unloading cycles due to the shuttling function, whereas permanent changes are observed upon repeated deformations to high strains due to breakage of the mechanical bond upon dethreading of the ring from the axle. This response allows one, at least conceptually, to monitor the actual deformation of polymer materials and examine mechanical damage that was inflicted in the past on the basis of an optical signal.
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Affiliation(s)
- Tatsuya Muramatsu
- Department of Materials Science and Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8552, Japan
| | - Yuji Okado
- Research Institute for Electronic Science, Hokkaido University, N20, W10, Kita-ku, Sapporo, Hokkaido 001-0020, Japan
| | - Hanna Traeger
- Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, CH-1700 Fribourg, Switzerland
| | - Stephen Schrettl
- Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, CH-1700 Fribourg, Switzerland
| | - Nobuyuki Tamaoki
- Research Institute for Electronic Science, Hokkaido University, N20, W10, Kita-ku, Sapporo, Hokkaido 001-0020, Japan
| | - Christoph Weder
- Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, CH-1700 Fribourg, Switzerland
| | - Yoshimitsu Sagara
- Department of Materials Science and Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8552, Japan.,JST-PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
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49
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Magrini T, Kiebala D, Grimm D, Nelson A, Schrettl S, Bouville F, Weder C, Studart AR. Tough Bioinspired Composites That Self-Report Damage. ACS APPLIED MATERIALS & INTERFACES 2021; 13:27481-27490. [PMID: 34076408 DOI: 10.1021/acsami.1c05964] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The increasing use of lightweight composite materials in structural applications requires the development of new damage monitoring technologies to ensure their safe use and prevent accidents. Although several molecular strategies have been proposed to report damage in polymers through mechanochromic responses, these approaches have not yet been translated into lightweight bioinspired composites for load-bearing applications. Here, we report on the development of bioinspired laminates of alternating polymer and nacre-like layers that combine optical translucency, high fracture toughness, and damage-reporting capabilities. The composites signal damage via a fluorescence color change that arises from the force activation of mechanophore molecules embedded in the material's polymer phase. A quantitative correlation between the applied strain and the fluorescence intensity was successfully established. We demonstrate that optical imaging of mechanically loaded composites allows for the localized detection of damage prior to fracture. This fluorescence-based self-reporting mechanism offers a promising approach for the early detection of damage in lightweight structural composites and can serve as a useful tool for the analysis of fracture processes in bulk transparent materials.
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Affiliation(s)
- Tommaso Magrini
- Complex Materials, Department of Materials, ETH Zürich, Zürich 8093, Switzerland
| | - Derek Kiebala
- Adolphe Merkle Institute, University of Fribourg, Fribourg 1700, Switzerland
| | - Dominique Grimm
- Complex Materials, Department of Materials, ETH Zürich, Zürich 8093, Switzerland
| | - Anna Nelson
- Complex Materials, Department of Materials, ETH Zürich, Zürich 8093, Switzerland
| | - Stephen Schrettl
- Adolphe Merkle Institute, University of Fribourg, Fribourg 1700, Switzerland
| | - Florian Bouville
- Centre for Advanced Structural Ceramics, Department of Materials, Imperial College London, London SW7 2AZ, United Kingdom
| | - Christoph Weder
- Adolphe Merkle Institute, University of Fribourg, Fribourg 1700, Switzerland
| | - André R Studart
- Complex Materials, Department of Materials, ETH Zürich, Zürich 8093, Switzerland
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50
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Baumann C, Stratigaki M, Centeno SP, Göstl R. Multicolor Mechanofluorophores for the Quantitative Detection of Covalent Bond Scission in Polymers. Angew Chem Int Ed Engl 2021; 60:13287-13293. [PMID: 33783112 PMCID: PMC8252433 DOI: 10.1002/anie.202101716] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 03/23/2021] [Indexed: 01/28/2023]
Abstract
The fracture of polymer materials is a multiscale process starting with the scission of a single molecular bond advancing to a site of failure within the bulk. Quantifying the bonds broken during this process remains a big challenge yet would help to understand the distribution and dissipation of macroscopic mechanical energy. We here show the design and synthesis of fluorogenic molecular optical force probes (mechanofluorophores) covering the entire visible spectrum in both absorption and emission. Their dual fluorescent character allows to track non-broken and broken bonds in dissolved and bulk polymers by fluorescence spectroscopy and microscopy. Importantly, we develop an approach to determine the absolute number and relative fraction of intact and cleaved bonds with high local resolution. We anticipate that our mechanofluorophores in combination with our quantification methodology will allow to quantitatively describe fracture processes in materials ranging from soft hydrogels to high-performance polymers.
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Affiliation(s)
- Christoph Baumann
- DWI—Leibniz Institute for Interactive MaterialsForckenbeckstr. 5052056AachenGermany
- Institute of Technical and Macromolecular ChemistryRWTH Aachen UniversityWorringerweg 152074AachenGermany
| | - Maria Stratigaki
- DWI—Leibniz Institute for Interactive MaterialsForckenbeckstr. 5052056AachenGermany
| | - Silvia P. Centeno
- DWI—Leibniz Institute for Interactive MaterialsForckenbeckstr. 5052056AachenGermany
- Institute of Physical ChemistryRWTH Aachen UniversityLandoltweg 252074AachenGermany
| | - Robert Göstl
- DWI—Leibniz Institute for Interactive MaterialsForckenbeckstr. 5052056AachenGermany
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