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Vialetto J, Ramakrishna SN, Stock S, von Klitzing R, Isa L. Modulating the conformation of microgels by complexation with inorganic nanoparticles. J Colloid Interface Sci 2024; 672:797-804. [PMID: 38870770 DOI: 10.1016/j.jcis.2024.05.163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Revised: 05/16/2024] [Accepted: 05/21/2024] [Indexed: 06/15/2024]
Abstract
HYPOTHESIS The complexation of microgels with rigid nanoparticles is an effective way to impart novel properties and functions to the resulting hybrid particles for applications such as in optics, catalysis, or for the stabilization of foams/emulsions. The nanoparticles affect the conformation of the polymer network, both in bulk aqueous environments and when the microgels are adsorbed at a fluid interface, in a non-trivial manner by modulating the microgel size, stiffness and apparent contact angle. EXPERIMENTS Here, we provide a detailed investigation, using light scattering, in-situ atomic force microscopy and nano-indentation experiments, of the interaction between poly(N-isopropylacrylamide) microgels and hydrophobized silica nanoparticles after mixing in aqueous suspension to shed light on the network reorganization upon nanoparticle incorporation. FINDINGS The addition of nanoparticles decreases the microgels' bulk swelling and thermal response. When adsorbed at an oil-water interface, a higher ratio of nanoparticles influences the microgel's stiffness as well as their hydrophobic/hydrophilic character by increasing their effective contact angle, consequently modulating the monolayer response upon interfacial compression. Overall, these results provide fundamental understanding on the complex conformation of hybrid microgels in different environments and give inspiration to design new materials where the combination of a soft polymer network and nanoparticles might result in additional functionalities.
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Affiliation(s)
- Jacopo Vialetto
- Department of Chemistry "Ugo Schiff", University of Florence, via della Lastruccia 3, 50019 Sesto Fiorentino (FI), Italy; Laboratory for Soft Materials and Interfaces, Department of Materials, ETH Zürich, Vladimir-Prelog-Weg 5, 8093 Zürich, Switzerland; Consorzio interuniversitario per lo sviluppo dei Sistemi a Grande Interfase (CSGI), via della Lastruccia 3, 50019 Sesto Fiorentino (FI), Italy.
| | - Shivaprakash N Ramakrishna
- Laboratory for Soft Materials and Interfaces, Department of Materials, ETH Zürich, Vladimir-Prelog-Weg 5, 8093 Zürich, Switzerland
| | - Sebastian Stock
- Institute for Condensed Matter Physics, Technische Universität Darmstadt, Hochschulstraße 8, 64289 Darmstadt, Germany
| | - Regine von Klitzing
- Institute for Condensed Matter Physics, Technische Universität Darmstadt, Hochschulstraße 8, 64289 Darmstadt, Germany
| | - Lucio Isa
- Laboratory for Soft Materials and Interfaces, Department of Materials, ETH Zürich, Vladimir-Prelog-Weg 5, 8093 Zürich, Switzerland
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2
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Linn JD, Rodriguez FA, Calabrese MA. Cosolvent incorporation modulates the thermal and structural response of PNIPAM/silyl methacrylate copolymers. SOFT MATTER 2024; 20:3322-3336. [PMID: 38536224 DOI: 10.1039/d4sm00246f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/18/2024]
Abstract
Polymers functionalized with inorganic silane groups have been used in wide-ranging applications due to the silane reactivity, which enables formation of covalently-crosslinked polymeric structures. Utilizing stimuli-responsive polymers in these hybrid systems can lead to smart and tunable behavior for sensing, drug delivery, and optical coatings. Previously, the thermoresponsive polymer poly(N-isopropyl acrylamide) (PNIPAM) functionalized with 3-(trimethoxysilyl)propyl methacrylate (TMA) demonstrated unique aqueous self-assembly and optical responses following temperature elevation. Here, we investigate how cosolvent addition, particularly ethanol and N,N-dimethyl formamide (DMF), impacts these transition temperatures, optical clouding, and structure formation in NIPAM/TMA copolymers. Versus purely aqueous systems, these solvent mixtures can introduce additional phase transitions and can alter the two-phase region boundaries based on temperature and solvent composition. Interestingly, TMA incorporation strongly alters phase boundaries in the water-rich regime for DMF-containing systems but not for ethanol-containing systems. Cosolvent species and content also alter the aggregation and assembly of NIPAM/TMA copolymers, but these effects depend on polymer architecture. For example, localizing the TMA towards one chain end in 'blocky' domains leads to formation of uniform micelles with narrow dispersities above the cloud point for certain solvent compositions. In contrast, polydisperse aggregates form in random copolymer and PNIPAM homopolymer solutions - the size of which depends on solvent composition. The resulting optical responses and thermoreversibility also depend strongly on cosolvent content and copolymer architecture. Cosolvent incorporation thus increases the versatility of inorganic-functionalized responsive polymers for diverse applications by providing a simple way to tune the structure size and optical response.
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Affiliation(s)
- Jason D Linn
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455, USA.
| | - Fabian A Rodriguez
- Department of Mechanical Engineering, The University of Texas Rio Grande Valley, Edinburg, TX 78539, USA
| | - Michelle A Calabrese
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455, USA.
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3
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Papadakis CM, Niebuur BJ, Schulte A. Thermoresponsive Polymers under Pressure with a Focus on Poly( N-isopropylacrylamide) (PNIPAM). LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:1-20. [PMID: 38149782 DOI: 10.1021/acs.langmuir.3c02398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2023]
Abstract
Pressure is a key variable in the phase behavior of responsive polymers, both for applications and from a fundamental point of view. In this feature article, we review recent developments, particularly applications of neutron techniques such as small-angle neutron scattering (SANS) and quasi-elastic neutron scattering (QENS), across the temperature-pressure phase diagram. These are complemented by kinetic SANS experiments following pressure jumps. In the prototype system poly(N-isopropylacrylamide) (PNIPAM), QENS revealed the pressure-dependent characteristics of hydration water around the lower critical solution temperature transition. The size, water content, and inner structure of the mesoglobules formed in the two-phase region depend strongly on pressure, as shown by SANS. Beside these changes at the phase transition, the mesoglobule formation at low pressure is determined by kinetic factors, namely the formation of a polymer-rich, rigid shell, which hampers further growth by coalescence. At high pressure, in contrast, the growth proceeds by diffusion-limited coalescence without any kinetic hindrance. The disintegration of the mesoglobules evolves either via chain release from their surface or via swelling, depending on the osmotic pressure of the water. Moreover, we report on the profound influence of pressure on the cononsolvency effect. In the temperature-pressure frame, the one-phase region is hugely expanded upon the addition of the cosolvent methanol. SANS experiments unveil the enthalpic and entropic contributions to the effective Flory-Huggins interaction parameter between the segments and the solvent mixture. QENS experiments demonstrate an increase in polymer associated water with pressure, whereas methanol is released. Correspondingly, the solvent phase becomes enriched in methanol, providing a mechanism for the breakdown of cononsolvency at a high pressure. Finally, we outline future opportunities for high-pressure studies of thermoresponsive polymers, with a focus on neutron methods.
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Affiliation(s)
- Christine M Papadakis
- TUM School of Natural Sciences, Physics Department, Soft Matter Physics Group, Technical University of Munich, James-Franck-Str. 1, 85748 Garching, Germany
| | - Bart-Jan Niebuur
- TUM School of Natural Sciences, Physics Department, Soft Matter Physics Group, Technical University of Munich, James-Franck-Str. 1, 85748 Garching, Germany
| | - Alfons Schulte
- Department of Physics and College of Optics and Photonics, University of Central Florida, 4111 Libra Drive, Orlando, Florida 32816-2385, United States
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4
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Hou J, Li B, Jang W, Yun J, Eyimegwu FM, Kim JH. Integration of Gold Nanoparticles into Crosslinker-Free Polymer Particles and Their Colloidal Catalytic Property. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:416. [PMID: 36770377 PMCID: PMC9920725 DOI: 10.3390/nano13030416] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 01/09/2023] [Accepted: 01/17/2023] [Indexed: 06/18/2023]
Abstract
This work demonstrates the incorporation of gold nanoparticles (AuNPs) into crosslinker-free poly(N-isopropylacrylamide), PNIPAM, particles in situ and the examination of their structural and catalytic properties. The formation process of the AuNPs across the crosslinker-free PNIPAM particles are compared to that of crosslinked PNIPAM particles. Given the relatively larger free volume across the crosslinker-free polymer network, the AuNPs formed by the in situ reduction of gold ions are detectably larger and more polydisperse, but their overall integration efficiency is slightly inferior. The structural features and stability of these composite particles are also examined in basic and alcoholic solvent environments, where the crosslinker-free PNIPAM particles still offer comparable physicochemical properties to the crosslinked PNIPAM particles. Interestingly, the crosslinker-free composite particles as a colloidal catalyst display a higher reactivity toward the homocoupling of phenylboronic acid and reveal the importance of the polymer network density. As such, the capability to prepare composite particles in a controlled polymer network and reactive metal nanoparticles, as well as understanding the structure-dependent physicochemical properties, can allow for the development of highly practical catalytic systems.
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Affiliation(s)
- Jian Hou
- School of Intelligent Manufacturing, Luoyang Institute of Science and Technology, Luoyang 471023, China
| | - Bin Li
- School of Intelligent Manufacturing, Luoyang Institute of Science and Technology, Luoyang 471023, China
- Henan International Joint Laboratory of Cutting Tools and Precision Machining, Luoyang Institute of Science and Technology, Luoyang 471023, China
| | - Wongi Jang
- Department of Chemistry, Illinois State University, Normal, IL 61790-4160, USA
| | - Jaehan Yun
- Department of Chemistry, Illinois State University, Normal, IL 61790-4160, USA
| | - Faith M Eyimegwu
- Department of Chemistry, Illinois State University, Normal, IL 61790-4160, USA
| | - Jun-Hyun Kim
- Department of Chemistry, Illinois State University, Normal, IL 61790-4160, USA
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5
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Liu B, Yan X, Zhao Z, Wang J, Feng J. Distinctly different solvation behaviors of poly( N, N-diethylacrylamide) gels in water/acetone and water/DMSO mixtures. Phys Chem Chem Phys 2022; 24:23893-23902. [PMID: 36165400 DOI: 10.1039/d2cp02144g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The solvation behaviors and intermolecular interactions of a poly(N,N-diethylacrylamide) (PDEA) gel network in water/DMSO and water/acetone mixtures have been investigated by variable-temperature high-resolution 1H MAS NMR. Unlike decreasing volume phase transition temperature (VPTT) of the typical thermosensitive poly(N-isopropylacrylamide) (PNIPAM) gel induced by both acetone and DMSO in a water-rich region, distinct phase transition behaviors are revealed for the PDEA gel. That is, acetone is found to increase the VPTT of PDEA directly in the water-rich region while DMSO is also found to increase the VPTT of PDEA at a very low concentration but then decrease the VPTT as the concentration further increases. The above distinctly different VPTT shifts of PDEA are attributed to the different polymer-cosolvent interactions in water/acetone and water/DMSO systems. DMSO molecules with a strong water affinity are preferentially excluded by the PDEA gel network, and can promote the volume phase transition by favoring the collapse of the PDEA gel network, while acetone molecules preferentially adsorbed on the polymer interact with PDEA via non-specific van der Waals interaction, which favors the swollen state of the PDEA gel.
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Affiliation(s)
- Biaolan Liu
- State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, Wuhan Center for Magnetic Resonance, Key Laboratory of Magnetic Resonance in Biological Systems, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China.
| | - Xiaoshuang Yan
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Zhihui Zhao
- State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, Wuhan Center for Magnetic Resonance, Key Laboratory of Magnetic Resonance in Biological Systems, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China. .,University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Jian Wang
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Jiwen Feng
- State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, Wuhan Center for Magnetic Resonance, Key Laboratory of Magnetic Resonance in Biological Systems, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China.
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6
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Mondal P, Chakraborty I, Chatterjee K. Injectable Adhesive Hydrogels for Soft tissue Reconstruction: A Materials Chemistry Perspective. CHEM REC 2022; 22:e202200155. [PMID: 35997710 DOI: 10.1002/tcr.202200155] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Revised: 07/30/2022] [Indexed: 11/09/2022]
Abstract
Injectable bioadhesives offer several advantages over conventional staples and sutures in surgery to seal and close incisions or wounds. Despite the growing research in recent years few injectable bioadhesives are available for clinical use. This review summarizes the key chemical features that enable the development and improvements in the use of polymeric injectable hydrogels as bioadhesives or sealants, their design requirements, the gelation mechanism, synthesis routes, and the role of adhesion mechanisms and strategies in different biomedical applications. It is envisaged that developing a deep understanding of the underlying materials chemistry principles will enable researchers to effectively translate bioadhesive technologies into clinically-relevant products.
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Affiliation(s)
- Pritiranjan Mondal
- Department of Materials Engineering, Indian Institute of Science, C.V. Raman Avenue, Bangalore, 560012, India
| | - Indranil Chakraborty
- Department of Materials Engineering, Indian Institute of Science, C.V. Raman Avenue, Bangalore, 560012, India
| | - Kaushik Chatterjee
- Department of Materials Engineering, Indian Institute of Science, C.V. Raman Avenue, Bangalore, 560012, India
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7
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Cononsolvency of the responsive polymer poly(N-isopropylacrylamide) in water/methanol mixtures: a dynamic light scattering study of the effect of pressure on the collective dynamics. Colloid Polym Sci 2022. [DOI: 10.1007/s00396-022-04987-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Abstract
The collective dynamics of 25 wt% poly(N-isopropylacrylamide) (PNIPAM) solutions in water or an 80:20 v/v water/methanol mixture are investigated in the one-phase region in dependence on pressure and temperature using dynamic light scattering. Throughout, two dynamic modes are observed, the fast one corresponding to the relaxation of the chain segments within the polymer blobs and the slow one to the relaxation of the blobs. A pressure scan in the one-phase region on an aqueous solution at 34.0 °C, i.e., slightly below the maximum of the coexistence line, reveals that the dynamic correlation length of the fast mode increases when the left and the right branch of the coexistence line are approached. Thus, the chains are rather swollen far away from the coexistence line, but contracted near the phase transition. Temperature scans of solutions in neat H2O or in H2O/CD3OD at 0.1, 130, and 200 MPa reveal that the dynamic correlation length of the fast mode shows critical behavior. However, the critical exponents are significantly larger than the value predicted by mean-field theory for the static correlation length, ν = 0.5, and the exponent is significantly larger for the solution in the H2O/CD3OD mixture than in neat H2O.
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8
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Synthesis, characterization and application of dual thermo- and solvent-responsive double-hydrophilic diblock copolymers of N-acryloylmorpholine and N-isopropylacrylamide. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.119053] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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9
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Wang P, Geiger C, Kreuzer LP, Widmann T, Reitenbach J, Liang S, Cubitt R, Henschel C, Laschewsky A, Papadakis CM, Müller-Buschbaum P. Poly(sulfobetaine)-Based Diblock Copolymer Thin Films in Water/Acetone Atmosphere: Modulation of Water Hydration and Co-nonsolvency-Triggered Film Contraction. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:6934-6948. [PMID: 35609178 DOI: 10.1021/acs.langmuir.2c00451] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The water swelling and subsequent solvent exchange including co-nonsolvency behavior of thin films of a doubly thermo-responsive diblock copolymer (DBC) are studied via spectral reflectance, time-of-flight neutron reflectometry, and Fourier transform infrared spectroscopy. The DBC consists of a thermo-responsive zwitterionic (poly(4-((3-methacrylamidopropyl) dimethylammonio) butane-1-sulfonate)) (PSBP) block, featuring an upper critical solution temperature transition in aqueous media but being insoluble in acetone, and a nonionic poly(N-isopropylmethacrylamide) (PNIPMAM) block, featuring a lower critical solution temperature transition in water, while being soluble in acetone. Homogeneous DBC films of 50-100 nm thickness are first swollen in saturated water vapor (H2O or D2O), before they are subjected to a contraction process by exposure to mixed saturated water/acetone vapor (H2O or D2O/acetone-d6 = 9:1 v/v). The affinity of the DBC film toward H2O is stronger than for D2O, as inferred from the higher film thickness in the swollen state and the higher absorbed water content, thus revealing a pronounced isotope sensitivity. During the co-solvent-induced switching by mixed water/acetone vapor, a two-step film contraction is observed, which is attributed to the delayed expulsion of water molecules and uptake of acetone molecules. The swelling kinetics are compared for both mixed vapors (H2O/acetone-d6 and D2O/acetone-d6) and with those of the related homopolymer films. Moreover, the concomitant variations of the local environment around the hydrophilic groups located in the PSBP and PNIPMAM blocks are followed. The first contraction step turns out to be dominated by the behavior of the PSBP block, whereas the second one is dominated by the PNIPMAM block. The unusual swelling and contraction behavior of the latter block is attributed to its co-nonsolvency behavior. Furthermore, we observe cooperative hydration effects in the DBC films, that is, both polymer blocks influence each other's solvation behavior.
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Affiliation(s)
- Peixi Wang
- Lehrstuhl für Funktionelle Materialien, Physik Department, Technische Universität München, James-Franck-Street 1, Garching 85748, Germany
| | - Christina Geiger
- Lehrstuhl für Funktionelle Materialien, Physik Department, Technische Universität München, James-Franck-Street 1, Garching 85748, Germany
| | - Lucas P Kreuzer
- Lehrstuhl für Funktionelle Materialien, Physik Department, Technische Universität München, James-Franck-Street 1, Garching 85748, Germany
| | - Tobias Widmann
- Lehrstuhl für Funktionelle Materialien, Physik Department, Technische Universität München, James-Franck-Street 1, Garching 85748, Germany
| | - Julija Reitenbach
- Lehrstuhl für Funktionelle Materialien, Physik Department, Technische Universität München, James-Franck-Street 1, Garching 85748, Germany
| | - Suzhe Liang
- Lehrstuhl für Funktionelle Materialien, Physik Department, Technische Universität München, James-Franck-Street 1, Garching 85748, Germany
| | - Robert Cubitt
- Institut-Laue-Langevin, 6 rue Jules Horowitz, Grenoble 38000, France
| | - Cristiane Henschel
- Institut für Chemie, Universität Potsdam, Karl-Liebknecht-Street 24-25, Potsdam-Golm 14476, Germany
| | - André Laschewsky
- Institut für Chemie, Universität Potsdam, Karl-Liebknecht-Street 24-25, Potsdam-Golm 14476, Germany
- Fraunhofer Institut für Angewandte Polymerforschung, Geiselberg Street 69, Potsdam-Golm 14476, Germany
| | - Christine M Papadakis
- Fachgebiet Physik weicher Materie, Physik Department, Technische Universität München, James-Franck-Street 1, Garching 85748, Germany
| | - Peter Müller-Buschbaum
- Lehrstuhl für Funktionelle Materialien, Physik Department, Technische Universität München, James-Franck-Street 1, Garching 85748, Germany
- Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, Lichtenberg Street 1, Garching 85748, Germany
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10
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Tavagnacco L, Zaccarelli E, Chiessi E. Modeling Solution Behavior of Poly( N-isopropylacrylamide): A Comparison between Water Models. J Phys Chem B 2022; 126:3778-3788. [PMID: 35491838 PMCID: PMC9150113 DOI: 10.1021/acs.jpcb.2c00637] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
![]()
Water is known to
play a fundamental role in determining the structure
and functionality of macromolecules. The same crucial contribution
is also found in the in silico description of polymer aqueous solutions.
In this work, we exploit the widely investigated synthetic polymer
poly(N-isopropylacrylamide) (PNIPAM) to understand
the effect of the adopted water model on its solution behavior and
to refine the computational setup. By means of atomistic molecular
dynamics simulations, we perform a comparative study of PNIPAM aqueous
solution using two advanced water models: TIP4P/2005 and TIP4P/Ice.
The conformation and hydration features of an atactic 30-mer at infinite
dilution are probed at a range of temperature and pressure suitable
to detect the coil-to-globule transition and to map the P–T
phase diagram. Although both water models can reproduce the temperature-induced
coil-to-globule transition at atmospheric pressure and the polymer
hydration enhancement that occurs with increasing pressure, the PNIPAM–TIP4P/Ice
solution shows better agreement with experimental findings. This result
can be attributed to a stronger interaction of TIP4P/Ice water with
both hydrophilic and hydrophobic groups of PNIPAM, as well as to a
less favorable contribution of the solvent entropy to the coil-to-globule
transition.
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Affiliation(s)
- Letizia Tavagnacco
- CNR-ISC and Department of Physics, Sapienza University of Rome, Piazzale A, Moro 2, Rome 00185, Italy
| | - Emanuela Zaccarelli
- CNR-ISC and Department of Physics, Sapienza University of Rome, Piazzale A, Moro 2, Rome 00185, Italy
| | - Ester Chiessi
- Department of Chemical Sciences and Technologies, University of Rome Tor Vergata, Via della Ricerca Scientifica I, Rome 00133, Italy
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11
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Bharadwaj S, Niebuur BJ, Nothdurft K, Richtering W, van der Vegt NFA, Papadakis CM. Cononsolvency of thermoresponsive polymers: where we are now and where we are going. SOFT MATTER 2022; 18:2884-2909. [PMID: 35311857 DOI: 10.1039/d2sm00146b] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Cononsolvency is an intriguing phenomenon where a polymer collapses in a mixture of good solvents. This cosolvent-induced modulation of the polymer solubility has been observed in solutions of several polymers and biomacromolecules, and finds application in areas such as hydrogel actuators, drug delivery, compound detection and catalysis. In the past decade, there has been a renewed interest in understanding the molecular mechanisms which drive cononsolvency with a predominant emphasis on its connection to the preferential adsorption of the cosolvent. Significant efforts have also been made to understand cononsolvency in complex systems such as micelles, block copolymers and thin films. In this review, we will discuss some of the recent developments from the experimental, simulation and theoretical fronts, and provide an outlook on the problems and challenges which are yet to be addressed.
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Affiliation(s)
- Swaminath Bharadwaj
- Technical University of Darmstadt, Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Computational Physical Chemistry Group, 64287 Darmstadt, Germany.
| | - Bart-Jan Niebuur
- Technical University of Munich, Physics Department, Soft Matter Physics Group, James-Franck-Str. 1, 85748 Garching, Germany
| | - Katja Nothdurft
- RWTH Aachen University, Institut für Physikalische Chemie, Landoltweg 2, 52056 Aachen, Germany, European Union
| | - Walter Richtering
- RWTH Aachen University, Institut für Physikalische Chemie, Landoltweg 2, 52056 Aachen, Germany, European Union
| | - Nico F A van der Vegt
- Technical University of Darmstadt, Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Computational Physical Chemistry Group, 64287 Darmstadt, Germany.
| | - Christine M Papadakis
- Technical University of Munich, Physics Department, Soft Matter Physics Group, James-Franck-Str. 1, 85748 Garching, Germany
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12
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Shah RA, Runge T, Ostertag TW, Tang S, Dziubla TD, Hilt JZ. Development of temperature-responsive polymeric gels with physical crosslinking due to intermolecular 𝜋-𝜋 interactions. POLYM INT 2022; 71:292-300. [PMID: 35695835 PMCID: PMC9173683 DOI: 10.1002/pi.6328] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Poly(N-isopropylacrylamide) PNIPAAm was polymerized with co-monomers containing a biphenyl moiety to create a unique thermoresponsive physically crosslinked system due to the presence of pi-pi interactions between the biphenyl moieties. The biphenyl monomers used were 2-phenylphenol monoacrylate (2PPMA) and 4-phenylphenol monoacrylate (4PPMA). These monomers were utilized to synthesize a set of polymers with biphenyl monomer (2PPMA/4PPMA) content from 2.5 to 7.5 mole percent and with initiator concentrations from 0.1 and 1.0 weight percent. The resulting polymers were characterized by various techniques, such as gel permeation chromatography (GPC), swelling studies and mechanical testing. The decrease in the average molecular weight of the polymers due to the increase in the concentration of initiator was confirmed by GPC results. Swelling studies confirmed the expected temperature dependent swelling properties and explored the impact of the biphenyl comonomers. These studies indicated that with the increase in biphenyl comonomers, the physical crosslinking increases which leads to decrease in the swelling ratio. The results from the mechanical tests also depict the effect of the concentration of biphenyl comonomers. These physically crosslinked polymeric systems with their unique properties have potential applications spanning environmental remediation/sensing, biomedicine, etc.
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Affiliation(s)
- Rishabh A. Shah
- Superfund Research Center, University of Kentucky, Lexington, KY 40536, USA,Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY 40506, USA
| | - Tyler Runge
- Department of Physics and Engineering, Washington and Lee University, Lexington, VA 24450, USA
| | - Thomas W. Ostertag
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY 40506, USA
| | - Shuo Tang
- Superfund Research Center, University of Kentucky, Lexington, KY 40536, USA,Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY 40506, USA
| | - Thomas D. Dziubla
- Superfund Research Center, University of Kentucky, Lexington, KY 40536, USA,Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY 40506, USA
| | - J. Zach Hilt
- Superfund Research Center, University of Kentucky, Lexington, KY 40536, USA,Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY 40506, USA,Author to whom correspondence should be addressed,
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13
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Rosi BP, Tavagnacco L, Comez L, Sassi P, Ricci M, Buratti E, Bertoldo M, Petrillo C, Zaccarelli E, Chiessi E, Corezzi S. Thermoresponsivity of poly(N-isopropylacrylamide) microgels in water-trehalose solution and its relation to protein behavior. J Colloid Interface Sci 2021; 604:705-718. [PMID: 34280768 DOI: 10.1016/j.jcis.2021.07.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 06/21/2021] [Accepted: 07/01/2021] [Indexed: 11/18/2022]
Abstract
HYPOTHESES Additives are commonly used to tune macromolecular conformational transitions. Among additives, trehalose is an excellent bioprotectant and among responsive polymers, PNIPAM is the most studied material. Nevertheless, their interaction mechanism so far has only been hinted without direct investigation, and, crucially, never elucidated in comparison to proteins. Detailed insights would help understand to what extent PNIPAM microgels can effectively be used as synthetic biomimetic materials, to reproduce and study, at the colloidal scale, isolated protein behavior and its sensitivity to interactions with specific cosolvents or cosolutes. EXPERIMENTS The effect of trehalose on the swelling behavior of PNIPAM microgels was monitored by dynamic light scattering; Raman spectroscopy and molecular dynamics simulations were used to explore changes of solvation and dynamics across the swelling-deswelling transition at the molecular scale. FINDINGS Strongly hydrated trehalose molecules develop water-mediated interactions with PNIPAM microgels, thereby preserving polymer hydration below and above the transition while drastically inhibiting local motions of the polymer and of its hydration shell. Our study, for the first time, demonstrates that slowdown of dynamics and preferential exclusion are the principal mechanisms governing trehalose effect on PNIPAM microgels, at odds with preferential adsorption of alcohols, but in full analogy with the behavior observed in trehalose-protein systems.
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Affiliation(s)
- Benedetta Petra Rosi
- Dipartimento di Fisica e Geologia, Università di Perugia, I-06123 Perugia, Italy
| | - Letizia Tavagnacco
- CNR-ISC, Sapienza Università di Roma, I-00185 Roma, Italy; Dipartimento di Fisica, Sapienza Università di Roma, I-00185 Roma, Italy
| | - Lucia Comez
- CNR-IOM, Dipartimento di Fisica e Geologia, Università di Perugia, I-06123 Perugia, Italy
| | - Paola Sassi
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, I-06123 Perugia, Italy
| | - Maria Ricci
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, I-06123 Perugia, Italy
| | - Elena Buratti
- CNR-ISC, Sapienza Università di Roma, I-00185 Roma, Italy; Dipartimento di Fisica, Sapienza Università di Roma, I-00185 Roma, Italy
| | - Monica Bertoldo
- Dipartimento di Scienze Chimiche, Farmaceutiche ed Agrarie, Università di Ferrara, I-44121 Ferrara, Italy; CNR-ISOF, Area della Ricerca, I-40129 Bologna, Italy
| | - Caterina Petrillo
- Dipartimento di Fisica e Geologia, Università di Perugia, I-06123 Perugia, Italy
| | - Emanuela Zaccarelli
- CNR-ISC, Sapienza Università di Roma, I-00185 Roma, Italy; Dipartimento di Fisica, Sapienza Università di Roma, I-00185 Roma, Italy
| | - Ester Chiessi
- Dipartimento di Scienze e Tecnologie Chimiche, Università di Roma "Tor Vergata", I-00133 Roma, Italy.
| | - Silvia Corezzi
- Dipartimento di Fisica e Geologia, Università di Perugia, I-06123 Perugia, Italy.
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14
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Abstract
Caffeine is not only a widely consumed active stimulant, but it is also a model molecule commonly used in pharmaceutical sciences. In this work, by performing quartz-crystal microbalance and neutron reflectometry experiments we investigate the interaction of caffeine molecules with a model lipid membrane. We determined that caffeine molecules are not able to spontaneously partition from an aqueous environment, enriched in caffeine, into a bilayer. Caffeine could be however included in solid-supported lipid bilayers if present with lipids during self-assembly. In this case, thanks to surface-sensitive techniques, we determined that caffeine molecules are preferentially located in the hydrophobic region of the membrane. These results are highly relevant for the development of new drug delivery vectors, as well as for a deeper understanding of the membrane permeation role of purine molecules.
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Affiliation(s)
- Letizia Tavagnacco
- CNR-ISC and Department of Physics, Sapienza University of Rome, Piazzale A. Moro 2, 00185 Rome, Italy
| | - Giacomo Corucci
- Institut Laue-Langevin, 71 avenue des Martyrs, 38000 Grenoble, France
| | - Yuri Gerelli
- Department of Life and Environmental Sciences, Marche Polytechnic University, Via Brecce Bianche, 60121 Ancona, Italy
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15
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Ko CH, Henschel C, Meledam GP, Schroer MA, Guo R, Gaetani L, Müller-Buschbaum P, Laschewsky A, Papadakis CM. Co-Nonsolvency Effect in Solutions of Poly(methyl methacrylate)- b-poly( N-isopropylacrylamide) Diblock Copolymers in Water/Methanol Mixtures. Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c00512] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Chia-Hsin Ko
- Physik-Department, Fachgebiet Physik Weicher Materie, Technische Universität München, James-Franck-Straße 1, 85748 Garching, Germany
| | - Cristiane Henschel
- Institut für Chemie, Universität Potsdam, Karl-Liebknecht-Straße 24-25, 14476 Potsdam, Golm, Germany
| | - Geethu P. Meledam
- Physik-Department, Fachgebiet Physik Weicher Materie, Technische Universität München, James-Franck-Straße 1, 85748 Garching, Germany
| | - Martin A. Schroer
- European Molecular Biology Laboratory, Hamburg Outstation, c/o Deutsches Elektronen-Synchrotron, Notkestr. 85, 22607 Hamburg, Germany
| | - Renjun Guo
- Physik-Department, Lehrstuhl für Funktionelle Materialien, Technische Universität München, James-Franck-Straße 1, 85748 Garching, Germany
| | - Luka Gaetani
- Physik-Department, Fachgebiet Physik Weicher Materie, Technische Universität München, James-Franck-Straße 1, 85748 Garching, Germany
| | - Peter Müller-Buschbaum
- Physik-Department, Lehrstuhl für Funktionelle Materialien, Technische Universität München, James-Franck-Straße 1, 85748 Garching, Germany
- Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, Lichtenbergstr. 1, 85748 Garching, Germany
| | - André Laschewsky
- Institut für Chemie, Universität Potsdam, Karl-Liebknecht-Straße 24-25, 14476 Potsdam, Golm, Germany
- Fraunhofer-Institut für Angewandte Polymerforschung, Geiselbergstraße 69, 14476 Potsdam, Golm, Germany
| | - Christine M. Papadakis
- Physik-Department, Fachgebiet Physik Weicher Materie, Technische Universität München, James-Franck-Straße 1, 85748 Garching, Germany
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16
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Niebuur BJ, Lohstroh W, Ko CH, Appavou MS, Schulte A, Papadakis CM. Pressure Dependence of Water Dynamics in Concentrated Aqueous Poly( N-isopropylacrylamide) Solutions with a Methanol Cosolvent. Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c00111] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Bart-Jan Niebuur
- Physik-Department, Fachgebiet Physik weicher Materie, Technische Universität München, James-Franck-Str. 1, 85748 Garching, Germany
| | - Wiebke Lohstroh
- Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, Lichtenbergstr. 1, 85748 Garching, Germany
| | - Chia-Hsin Ko
- Physik-Department, Fachgebiet Physik weicher Materie, Technische Universität München, James-Franck-Str. 1, 85748 Garching, Germany
| | - Marie-Sousai Appavou
- Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Forschungszentrum Jülich GmbH, Lichtenbergstr. 1, 85748 Garching, Germany
| | - Alfons Schulte
- Department of Physics and College of Optics and Photonics, University of Central Florida, 4111 Libra Drive, Orlando, Florida 32816-2385, United States
| | - Christine M. Papadakis
- Physik-Department, Fachgebiet Physik weicher Materie, Technische Universität München, James-Franck-Str. 1, 85748 Garching, Germany
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17
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Tavagnacco L, Chiessi E, Zaccarelli E. Molecular insights on poly( N-isopropylacrylamide) coil-to-globule transition induced by pressure. Phys Chem Chem Phys 2021; 23:5984-5991. [PMID: 33666621 PMCID: PMC8247264 DOI: 10.1039/d0cp06452a] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 02/17/2021] [Indexed: 12/17/2022]
Abstract
By using extensive all-atom molecular dynamics simulations of an atactic linear polymer chain, we provide microscopic insights into poly(N-isopropylacrylamide) (PNIPAM) coil-to-globule transition addressing the roles played by both temperature and pressure. We detect a coil-to-globule transition up to large pressures, showing a reentrant behavior of the critical temperature with increasing pressure in agreement with experimental observations. Furthermore, again confirming the experimental findings, we report the existence at high pressures of a new kind of globular state. It is characterized by a more structured hydration shell that is closer to PNIPAM hydrophobic domains, as compared to the globular state observed at atmospheric pressure. Our results highlight that temperature and pressure induce a PNIPAM coil-to-globule transition through different molecular mechanisms, opening the way for a systematic use of both thermodynamic variables to tune the location of the transition and the properties of the associated swollen/collapsed states.
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Affiliation(s)
- Letizia Tavagnacco
- CNR-ISC and Department of Physics, Sapienza University of Rome, Piazzale A. Moro 2, 00185, Rome, Italy.
| | - Ester Chiessi
- Department of Chemical Sciences and Technologies, University of Rome Tor Vergata, Via della Ricerca Scientifica I, 00133, Rome, Italy.
| | - Emanuela Zaccarelli
- CNR-ISC and Department of Physics, Sapienza University of Rome, Piazzale A. Moro 2, 00185, Rome, Italy.
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18
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Arai N, Koishi T, Ebisuzaki T. Nanotube Active Water Pump Driven by Alternating Hydrophobicity. ACS NANO 2021; 15:2481-2489. [PMID: 33534546 DOI: 10.1021/acsnano.0c06493] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Water transport must be efficiency controlled for the future sustainability of life. Various water transport systems using carbon nanotubes have been proposed in recent years. Although these systems are more permeable than aquaporins, their water transport is passive. In this study, we successfully demonstrate an active water pump driven by simple hydrophobic interaction through computer simulation. Even in the absence of a pressure- or density-gradient, the proposed pump can actively transport water molecules by alternately switching the hydrophobicity of the pump surface. The water transport rate can be easily controlled by varying the time interval of switching. The pump with optimized switching time exhibits prominent water permeance. The results obtained herein can be applied in various water transport technologies because of the simple mechanics. The proposed water pump has the potential to realize an effective device such as a low-energy artificial purification system.
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Affiliation(s)
- Noriyoshi Arai
- Department of Mechanical Engineering, Keio University, Yokohama 223-8522, Japan
- Computational Astrophysics Laboratory, RIKEN, Wako, Saitama 351-0198, Japan
| | - Takahiro Koishi
- Department of Applied Physics, University of Fukui, Bunkyo, Fukui 910-8507, Japan
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19
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Nothdurft K, Müller DH, Mürtz SD, Meyer AA, Guerzoni LPB, Jans A, Kühne AJC, De Laporte L, Brands T, Bardow A, Richtering W. Is the Microgel Collapse a Two-Step Process? Exploiting Cononsolvency to Probe the Collapse Dynamics of Poly- N-isopropylacrylamide (pNIPAM). J Phys Chem B 2021; 125:1503-1512. [PMID: 33503378 DOI: 10.1021/acs.jpcb.0c10430] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Many applications of responsive microgels rely on the fast adaptation of the polymer network. However, the underlying dynamics of the de-/swelling process of the gels have not been fully understood. In the present work, we focus on the collapse kinetics of poly-N-isopropylacrylamide (pNIPAM) microgels due to cononsolvency. Cononsolvency means that either of the pure solvents, e.g., pure water or pure methanol, act as a so-called good solvent, leading to a swollen state of the polymer network. However, in mixtures of water and methanol, the previously swollen network undergoes a drastic volume loss. To further elucidate the cononsolvency transition, pNIPAM microgels with diameters between 20 and 110 μm were synthesized by microfluidics. To follow the dynamics, pure water was suddenly exchanged with an unfavorable mixture of 20 mol% methanol (solvent-jump) within a microfluidic channel. The dynamic response of the microgels was investigated by optical and fluorescence microscopy and Raman microspectroscopy. The experimental data provide unique and detailed insight into the size-dependent kinetics of the volume phase transition due to cononsolvency. The change in the microgel's diameter over time points to a two-step process of the microgel collapse with a biexponential behavior. Furthermore, the dependence between the two time constants from this biexponential behavior and the microgel's diameter in the collapsed state deviates from the square-power law proposed by Tanaka and Fillmore [ J. Chem. Phys. 1979, 70, 1214-1218]. The deviation is discussed considering the adhesion-induced deformation of the gels and the physical processes underlying the collapse.
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Affiliation(s)
- Katja Nothdurft
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, 52056 Aachen, Germany
| | - David H Müller
- Institute of Technical Thermodynamics, RWTH Aachen University, Schinkelstr. 8, 52062 Aachen, Germany
| | - Sonja D Mürtz
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, 52056 Aachen, Germany
| | - Anna A Meyer
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, 52056 Aachen, Germany
| | - Luis P B Guerzoni
- DWI-Leibniz Institute for Interactive Materials, Forckenbeckstr. 50, 52074 Aachen, Germany
| | - Alexander Jans
- DWI-Leibniz Institute for Interactive Materials, Forckenbeckstr. 50, 52074 Aachen, Germany
| | - Alexander J C Kühne
- DWI-Leibniz Institute for Interactive Materials, Forckenbeckstr. 50, 52074 Aachen, Germany
| | - Laura De Laporte
- DWI-Leibniz Institute for Interactive Materials, Forckenbeckstr. 50, 52074 Aachen, Germany.,Institute of Technical and Macromolecular Chemistry, RWTH Aachen, Worringerweg 1-2, 52074 Aachen, Germany
| | - Thorsten Brands
- Institute of Technical Thermodynamics, RWTH Aachen University, Schinkelstr. 8, 52062 Aachen, Germany
| | - André Bardow
- Institute of Technical Thermodynamics, RWTH Aachen University, Schinkelstr. 8, 52062 Aachen, Germany.,Department of Mechanical and Process Engineering, ETH Zürich, Tannenstr. 3, 8092 Zürich, Switzerland
| | - Walter Richtering
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, 52056 Aachen, Germany.,DWI-Leibniz Institute for Interactive Materials, Forckenbeckstr. 50, 52074 Aachen, Germany
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20
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Kreuzer LP, Lindenmeir C, Geiger C, Widmann T, Hildebrand V, Laschewsky A, Papadakis CM, Müller-Buschbaum P. Poly(sulfobetaine) versus Poly( N-isopropylmethacrylamide): Co-Nonsolvency-Type Behavior of Thin Films in a Water/Methanol Atmosphere. Macromolecules 2021. [DOI: 10.1021/acs.macromol.0c02281] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Lucas P. Kreuzer
- Lehrstuhl für Funktionelle Materialien, Physik Department, Technische Universität München, James-Franck-Str. 1, 85748 Garching, Germany
| | - Christoph Lindenmeir
- Lehrstuhl für Funktionelle Materialien, Physik Department, Technische Universität München, James-Franck-Str. 1, 85748 Garching, Germany
| | - Christina Geiger
- Lehrstuhl für Funktionelle Materialien, Physik Department, Technische Universität München, James-Franck-Str. 1, 85748 Garching, Germany
| | - Tobias Widmann
- Lehrstuhl für Funktionelle Materialien, Physik Department, Technische Universität München, James-Franck-Str. 1, 85748 Garching, Germany
| | - Viet Hildebrand
- Institut für Chemie, Universität Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam-Golm, Germany
| | - André Laschewsky
- Institut für Chemie, Universität Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam-Golm, Germany
- Fraunhofer Institut für Angewandte Polymerforschung, Geiselbergstr. 69, 14476 Potsdam-Golm, Germany
| | - Christine M. Papadakis
- Fachgebiet Physik weicher Materie, Physik Department, Technische Universität München, James-Franck-Str. 1, 85748 Garching, Germany
| | - Peter Müller-Buschbaum
- Lehrstuhl für Funktionelle Materialien, Physik Department, Technische Universität München, James-Franck-Str. 1, 85748 Garching, Germany
- Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, Lichtenbergstr. 1, 85748 Garching, Germany
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21
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Quoika PK, Podewitz M, Wang Y, Kamenik AS, Loeffler JR, Liedl KR. Thermosensitive Hydration of Four Acrylamide-Based Polymers in Coil and Globule Conformations. J Phys Chem B 2020; 124:9745-9756. [PMID: 33054215 PMCID: PMC7604866 DOI: 10.1021/acs.jpcb.0c07232] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
![]()
To
characterize the thermosensitive coil–globule transition in
atomistic detail, the conformational dynamics of linear polymer chains
of acrylamide-based polymers have been investigated at multiple temperatures.
Therefore, molecular dynamic simulations of 30mers of polyacrylamide
(AAm), poly-N-methylacrylamide (NMAAm), poly-N-ethylacrylamide (NEAAm), and poly-N-isopropylacrylamide
(NIPAAm) have been performed at temperatures ranging from 250 to 360
K for 2 μs. While two of the polymers are known to exhibit thermosensitivity
(NEAAm, NIPAAm), no thermosensitivity is observed for AAm and NMAAm
in aqueous solution. Our computer simulations consistently reproduce
these properties. To understand the thermosensitivity of the respective
polymers, the conformational ensembles at different temperatures have
been separated according to the coil–globule transition. The
coil and globule conformational ensembles were exhaustively analyzed
in terms of hydrogen bonding with the solvent, the change of the solvent
accessible surface, and enthalpic contributions. Surprisingly, independent
of different thermosensitive properties of the four polymers, the
surface affinity to water of coil conformations is higher than for
globule conformations. Therefore, polymer–solvent interactions
stabilize coil conformations at all temperatures. Nevertheless, the
enthalpic contributions alone cannot explain the differences in thermosensitivity.
This clearly implies that entropy is the distinctive factor for thermosensitivity.
With increasing side chain length, the lifetime of the hydrogen bonds
between the polymer surface and water is extended. Thus, we surmise
that a longer side chain induces a larger entropic penalty due to
immobilization of water molecules.
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Affiliation(s)
- Patrick K Quoika
- Institute of General, Inorganic and Theoretical Chemistry, and Centre of Molecular Biosciences University of Innsbruck, Innsbruck, A-6020 Austria
| | - Maren Podewitz
- Institute of General, Inorganic and Theoretical Chemistry, and Centre of Molecular Biosciences University of Innsbruck, Innsbruck, A-6020 Austria
| | - Yin Wang
- Institute of General, Inorganic and Theoretical Chemistry, and Centre of Molecular Biosciences University of Innsbruck, Innsbruck, A-6020 Austria
| | - Anna S Kamenik
- Institute of General, Inorganic and Theoretical Chemistry, and Centre of Molecular Biosciences University of Innsbruck, Innsbruck, A-6020 Austria
| | - Johannes R Loeffler
- Institute of General, Inorganic and Theoretical Chemistry, and Centre of Molecular Biosciences University of Innsbruck, Innsbruck, A-6020 Austria
| | - Klaus R Liedl
- Institute of General, Inorganic and Theoretical Chemistry, and Centre of Molecular Biosciences University of Innsbruck, Innsbruck, A-6020 Austria
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22
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Frenzel L, Lokteva I, Koof M, Narayanan S, Grübel G, Lehmkühler F. Influence of TMAO as co-solvent on the gelation of silica-PNIPAm core-shell nanogels at intermediate volume fractions. Chemphyschem 2020; 21:1318-1325. [PMID: 32250508 PMCID: PMC7318175 DOI: 10.1002/cphc.202000114] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 03/20/2020] [Indexed: 12/29/2022]
Abstract
We study the structure and dynamics of poly(N-isopropylacrylamide) (PNIPAm) core-shell nanogels dispersed in aqueous trimethylamine N-oxide (TMAO) solutions by means of small-angle X-ray scattering and X-ray photon correlation spectroscopy (XPCS). Upon increasing the temperature above the lower critical solution temperature of PNIPAm at 33 °C, a colloidal gel is formed as identified by an increase of I(q) at small q as well as a slowing down of sample dynamics by various orders of magnitude. With increasing TMAO concentration the gelation transition shifts linearly to lower temperatures. Above a TMAO concentration of approximately 0.40 mol/L corresponding to a 1 : 1 ratio of TMAO and NIPAm groups, collapsed PNIPAm states are found for all temperatures without any gelation transition. This suggests that reduction of PNIPAm-water hydrogen bonds due to the presence of TMAO results in a stabilisation of the collapsed PNIPAm state and suppresses gelation of the nanogel.
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Affiliation(s)
- Lara Frenzel
- Deutsches Elektronen-Synchrotron DESYNotkestr. 8522607HamburgGermany
- The Hamburg Centre for Ultrafast ImagingLuruper Chaussee 14922761HamburgGermany
| | - Irina Lokteva
- Deutsches Elektronen-Synchrotron DESYNotkestr. 8522607HamburgGermany
- The Hamburg Centre for Ultrafast ImagingLuruper Chaussee 14922761HamburgGermany
| | - Michael Koof
- Deutsches Elektronen-Synchrotron DESYNotkestr. 8522607HamburgGermany
- The Hamburg Centre for Ultrafast ImagingLuruper Chaussee 14922761HamburgGermany
| | - Suresh Narayanan
- Advanced Photon SourceArgonne National LaboratoryArgonneIllinois60439United States
| | - Gerhard Grübel
- Deutsches Elektronen-Synchrotron DESYNotkestr. 8522607HamburgGermany
- The Hamburg Centre for Ultrafast ImagingLuruper Chaussee 14922761HamburgGermany
| | - Felix Lehmkühler
- Deutsches Elektronen-Synchrotron DESYNotkestr. 8522607HamburgGermany
- The Hamburg Centre for Ultrafast ImagingLuruper Chaussee 14922761HamburgGermany
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23
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Zanatta M, Tavagnacco L, Buratti E, Chiessi E, Natali F, Bertoldo M, Orecchini A, Zaccarelli E. Atomic scale investigation of the volume phase transition in concentrated PNIPAM microgels. J Chem Phys 2020; 152:204904. [PMID: 32486676 DOI: 10.1063/5.0007112] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Combining elastic incoherent neutron scattering and differential scanning calorimetry, we investigate the occurrence of the volume phase transition (VPT) in very concentrated poly-(N-isopropyl-acrylamide) (PNIPAM) microgel suspensions, from a polymer weight fraction of 30 wt. % up to dry conditions. Although samples are arrested at the macroscopic scale, atomic degrees of freedom are equilibrated and can be probed in a reproducible way. A clear signature of the VPT is present as a sharp drop in the mean square displacement of PNIPAM hydrogen atoms obtained by neutron scattering. As a function of concentration, the VPT gets smoother as dry conditions are approached, whereas the VPT temperature shows a minimum at about 43 wt. %. This behavior is qualitatively confirmed by calorimetry measurements. Molecular dynamics simulations are employed to complement experimental results and gain further insights into the nature of the VPT, confirming that it involves the formation of an attractive gel state between the microgels. Overall, these results provide evidence that the VPT in PNIPAM-based systems can be detected at different time- and length-scales as well as under overcrowded conditions.
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Affiliation(s)
- M Zanatta
- Department of Physics, University of Trento, I-38123 Trento, Italy
| | - L Tavagnacco
- CNR-ISC and Department of Physics, Sapienza University of Rome, I-00185 Roma, Italy
| | - E Buratti
- CNR-ISC and Department of Physics, Sapienza University of Rome, I-00185 Roma, Italy
| | - E Chiessi
- Department of Chemical Sciences and Technologies, University of Rome Tor Vergata, I-00133 Roma, Italy
| | - F Natali
- CNR-IOM, Operative Group in Grenoble (OGG), c/o Institut Laue Langevin, F-38042 Grenoble, France
| | - M Bertoldo
- Department of Chemical and Pharmaceutical Sciences, University of Ferrara, I-44121 Ferrara, Italy
| | - A Orecchini
- Department of Physics and Geology, University of Perugia, I-06123 Perugia, Italy
| | - E Zaccarelli
- CNR-ISC and Department of Physics, Sapienza University of Rome, I-00185 Roma, Italy
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