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Jaik TG, Ciubini B, Frascella F, Jonas U. Thermal Response and Thermochromism of Methyl Red-Based Copolymer Systems - Coupled Responsiveness in Critical Solution Behaviour and Optical Absorption Properties. Polym Chem 2022. [DOI: 10.1039/d1py01361k] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Until now, only limited experimental knowledge and sparse theoretical treatment about the mechanisms of thermochromism of azo dyes in solution has been available. Especially the coupling of thermoresponsiveness of polymers...
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2
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Lian L, Liu L, Ding Y, Hua Z, Liu G. Specific Anion Effects on Charged-Neutral Random Copolymers: Interplay between Different Anion-Polymer Interactions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:1697-1706. [PMID: 33499598 DOI: 10.1021/acs.langmuir.0c02907] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The study of ion specificities of charged-neutral random copolymers is of great importance for understanding specific ion effects on natural macromolecules. In the present work, we have investigated the specific anion effects on the thermoresponsive behavior of poly([2-(methacryloyloxy)ethyl trimethylammonium chloride]-co-N-isopropylacrylamide) [P(METAC-co-NIPAM)] random copolymers. Our study demonstrates that the anion specificities of the P(METAC-co-NIPAM) copolymers are dependent on their chemical compositions. The specific anion effects on the copolymers with high mole fractions of poly(N-isopropylacrylamide) (PNIPAM) are similar to those on the PNIPAM homopolymer. As the mole fraction of PNIPAM decreases to a certain value, a V-shaped anion series can be observed in terms of the anion-specific cloud point temperature of the copolymer, as induced by the interplay between different anion-polymer interactions. Our study also suggests that both the direct and the indirect anion-polymer interactions contribute to the anion specificities of the copolymers. This work would improve our understanding of the relationship between the ion specificities and the ion-macromolecule interactions for naturally occurring macromolecules.
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Affiliation(s)
- Leilei Lian
- Hefei National Laboratory for Physical Sciences at the Microscale, Key Laboratory of Surface and Interface Chemistry and Energy Catalysis of Anhui Higher Education Institutes, Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, P. R. China
| | - Lvdan Liu
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, P. R. China
| | - Yanwei Ding
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, P. R. China
| | - Zan Hua
- Biomass Molecular Engineering Center, Department of Materials Science and Engineering, Anhui Agricultural University, Hefei 230036, P. R. China
| | - Guangming Liu
- Hefei National Laboratory for Physical Sciences at the Microscale, Key Laboratory of Surface and Interface Chemistry and Energy Catalysis of Anhui Higher Education Institutes, Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, P. R. China
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3
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Competitive specific ion effects in mixed salt solutions on a thermoresponsive polymer brush. J Colloid Interface Sci 2020; 586:292-304. [PMID: 33189318 DOI: 10.1016/j.jcis.2020.10.092] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 10/21/2020] [Accepted: 10/22/2020] [Indexed: 11/22/2022]
Abstract
HYPOTHESIS Grafted poly(ethylene glycol) methyl ether methacrylate (POEGMA) copolymer brushes change conformation in response to temperature ('thermoresponse'). In the presence of different ions the thermoresponse of these coatings is dramatically altered. These effects are complex and poorly understood with no all-inclusive predictive theory of specific ion effects. As natural environments are composed of mixed electrolytes, it is imperative we understand the interplay of different ions for future applications. We hypothesise anion mixtures from the same end of the Hofmeister series (same-type anions) will exhibit non-additive and competitive behaviour. EXPERIMENTS The behaviour of POEGMA brushes, synthesised via surface-initiated ARGET-ATRP, in both single and mixed aqueous electrolyte solutions was characterised with ellipsometry and neutron reflectometry as a function of temperature. FINDINGS In mixed fluoride and chloride aqueous electrolytes (salting-out ions), or mixed thiocyanate and iodide aqueous electrolytes (salting-in ions), a non-monotonic concentration-dependent influence of the two anions on the thermoresponse of the brush was observed. A new term, δ, has been defined to quantitively describe synergistic or antagonistic behaviour. This study determined the specific ion effects imparted by salting-out ions are dependent on available solvent molecules, whereas the influence of salting-in ions is dependent on the interactions of the anions and polymer chains.
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4
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Murdoch TJ, Humphreys BA, Johnson EC, Webber GB, Wanless EJ. Specific ion effects on thermoresponsive polymer brushes: Comparison to other architectures. J Colloid Interface Sci 2018; 526:429-450. [DOI: 10.1016/j.jcis.2018.04.086] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 04/20/2018] [Accepted: 04/23/2018] [Indexed: 02/06/2023]
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5
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Li S, Ye S, Liu G. Specific Ion Effects on Protein Thermal Aggregation from Dilute Solutions to Crowded Environments. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:4289-4297. [PMID: 29566333 DOI: 10.1021/acs.langmuir.8b00294] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We have investigated specific ion effects on protein thermal aggregation from dilute solutions to crowded environments. Ovalbumin and poly(ethylene glycol) have been employed as the model protein and crowding agent, respectively. Our studies demonstrate that the rate-limiting step of ovalbumin thermal aggregation is changed from the aggregation of unfolded protein molecules to the unfolding of the protein molecules, when the solution conditions are varied from a dilute solution to a crowded environment. The specific ion effects acting on the thermal aggregation of ovalbumin generated by kosmotropic and chaotropic ions are different. The thermal aggregation of ovalbumin molecules is promoted by kosmotropic anions in dilute solutions via an increase in protein hydrophobic interactions. In contrast, ovalbumin thermal aggregation is facilitated by chaotropic ions in crowded environments through accelerated unfolding of protein molecules. Therefore, there are distinct mechanisms causing the ion specificities of protein thermal aggregation between dilute solutions and crowded environments. The ion specificities are dominated by ion-specific hydrophobic interactions between protein molecules and ion-specific unfolding of protein molecules in dilute solutions and crowded environments, respectively.
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Affiliation(s)
- Shuling Li
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemical Physics , University of Science and Technology of China , Hefei , P. R. China 230026
| | - Shuji Ye
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemical Physics , University of Science and Technology of China , Hefei , P. R. China 230026
| | - Guangming Liu
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemical Physics , University of Science and Technology of China , Hefei , P. R. China 230026
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6
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Umapathi R, Reddy PM, Rani A, Venkatesu P. Influence of additives on thermoresponsive polymers in aqueous media: a case study of poly(N-isopropylacrylamide). Phys Chem Chem Phys 2018; 20:9717-9744. [DOI: 10.1039/c7cp08172c] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Thermoresponsive polymers (TRPs) in different solvent media have been studied over a long period and are important from both scientific and technical points of view.
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Affiliation(s)
| | - P. Madhusudhana Reddy
- Department of Chemistry
- University of Delhi
- Delhi-110 007
- India
- Department of Chemical Engineering
| | - Anjeeta Rani
- Department of Chemistry
- University of Delhi
- Delhi-110 007
- India
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7
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Reddy PM, Hsieh SR, Chang CJ, Leong YY, Chen JK, Lee MC. Amplification of Hofmeister effect on poly( n -isopropylacrylamide) by crown ether. Colloids Surf A Physicochem Eng Asp 2017. [DOI: 10.1016/j.colsurfa.2017.05.037] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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8
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Conzatti G, Cavalie S, Combes C, Torrisani J, Carrere N, Tourrette A. PNIPAM grafted surfaces through ATRP and RAFT polymerization: Chemistry and bioadhesion. Colloids Surf B Biointerfaces 2017; 151:143-155. [DOI: 10.1016/j.colsurfb.2016.12.007] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 11/25/2016] [Accepted: 12/07/2016] [Indexed: 12/23/2022]
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9
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Okur HI, Hladílková J, Rembert KB, Cho Y, Heyda J, Dzubiella J, Cremer PS, Jungwirth P. Beyond the Hofmeister Series: Ion-Specific Effects on Proteins and Their Biological Functions. J Phys Chem B 2017; 121:1997-2014. [PMID: 28094985 DOI: 10.1021/acs.jpcb.6b10797] [Citation(s) in RCA: 411] [Impact Index Per Article: 58.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Ions differ in their ability to salt out proteins from solution as expressed in the lyotropic or Hofmeister series of cations and anions. Since its first formulation in 1888, this series has been invoked in a plethora of effects, going beyond the original salting out/salting in idea to include enzyme activities and the crystallization of proteins, as well as to processes not involving proteins like ion exchange, the surface tension of electrolytes, or bubble coalescence. Although it has been clear that the Hofmeister series is intimately connected to ion hydration in homogeneous and heterogeneous environments and to ion pairing, its molecular origin has not been fully understood. This situation could have been summarized as follows: Many chemists used the Hofmeister series as a mantra to put a label on ion-specific behavior in various environments, rather than to reach a molecular level understanding and, consequently, an ability to predict a particular effect of a given salt ion on proteins in solutions. In this Feature Article we show that the cationic and anionic Hofmeister series can now be rationalized primarily in terms of specific interactions of salt ions with the backbone and charged side chain groups at the protein surface in solution. At the same time, we demonstrate the limitations of separating Hofmeister effects into independent cationic and anionic contributions due to the electroneutrality condition, as well as specific ion pairing, leading to interactions of ions of opposite polarity. Finally, we outline the route beyond Hofmeister chemistry in the direction of understanding specific roles of ions in various biological functionalities, where generic Hofmeister-type interactions can be complemented or even overruled by particular steric arrangements in various ion binding sites.
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Affiliation(s)
- Halil I Okur
- Laboratory for Fundamental BioPhotonics (LBP), Institute of Bioengineering (IBI), School of Engineering (STI), École Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne, Switzerland
| | - Jana Hladílková
- Institute of Organic Chemistry and Biochemistry, The Czech Academy of Sciences , Flemingovo nam. 2, 16610 Prague 6, Czech Republic.,Division of Theoretical Chemistry, Lund University , P.O.B. 124, SE-22100 Lund, Sweden
| | | | - Younhee Cho
- Department of Chemistry, Texas A&M University , College Station 77843, Texas, United States
| | - Jan Heyda
- Institut für Weiche Materie und Funktionale Materialien, Helmholtz-Zentrum Berlin für Materialien und Energie , Hahn-Meitner Platz 1, 14109 Berlin, Germany.,Department of Physical Chemistry, University of Chemistry and Technology, Prague , Technická 5, 16628 Prague 6, Czech Republic
| | - Joachim Dzubiella
- Institut für Weiche Materie und Funktionale Materialien, Helmholtz-Zentrum Berlin für Materialien und Energie , Hahn-Meitner Platz 1, 14109 Berlin, Germany.,Institut für Physik, Humboldt-Universität zu Berlin , Newtonstrasse 15, 12489 Berlin, Germany
| | | | - Pavel Jungwirth
- Institute of Organic Chemistry and Biochemistry, The Czech Academy of Sciences , Flemingovo nam. 2, 16610 Prague 6, Czech Republic
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10
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Chen S, Wang K, Zhang W. A new thermoresponsive polymer of poly(N-acryloylsarcosine methyl ester) with a tunable LCST. Polym Chem 2017. [DOI: 10.1039/c7py00274b] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
A thermoresponsive polymer of the tertiary amide-based polyacrylamide, PNASME, was synthesized and its tunable thermoresponse was investigated.
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Affiliation(s)
- Shengli Chen
- Key Laboratory of Functional Polymer Materials of the Ministry of Education
- Institute of Polymer Chemistry
- College of Chemistry
- Nankai University
- Tianjin 300071
| | - Ke Wang
- Key Laboratory of Functional Polymer Materials of the Ministry of Education
- Institute of Polymer Chemistry
- College of Chemistry
- Nankai University
- Tianjin 300071
| | - Wangqing Zhang
- Key Laboratory of Functional Polymer Materials of the Ministry of Education
- Institute of Polymer Chemistry
- College of Chemistry
- Nankai University
- Tianjin 300071
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11
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Wang J, Wang N, Liu B, Bai J, Gong P, Ru G, Feng J. Preferential adsorption of the additive is not a prerequisite for cononsolvency in water-rich mixtures. Phys Chem Chem Phys 2017; 19:30097-30106. [DOI: 10.1039/c7cp04384h] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
NMR studies reveal the distinct molecular interactions accounting for cononsolvency.
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Affiliation(s)
- Jian Wang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics
- Wuhan Institute of Physics and Mathematics
- Chinese Academy of Science
- Wuhan 430071
- P. R. China
| | - Nian Wang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics
- Wuhan Institute of Physics and Mathematics
- Chinese Academy of Science
- Wuhan 430071
- P. R. China
| | - Biaolan Liu
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics
- Wuhan Institute of Physics and Mathematics
- Chinese Academy of Science
- Wuhan 430071
- P. R. China
| | - Jia Bai
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics
- Wuhan Institute of Physics and Mathematics
- Chinese Academy of Science
- Wuhan 430071
- P. R. China
| | - Pei Gong
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics
- Wuhan Institute of Physics and Mathematics
- Chinese Academy of Science
- Wuhan 430071
- P. R. China
| | - Geying Ru
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics
- Wuhan Institute of Physics and Mathematics
- Chinese Academy of Science
- Wuhan 430071
- P. R. China
| | - Jiwen Feng
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics
- Wuhan Institute of Physics and Mathematics
- Chinese Academy of Science
- Wuhan 430071
- P. R. China
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12
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Liu L, Kou R, Liu G. Ion specificities of artificial macromolecules. SOFT MATTER 2016; 13:68-80. [PMID: 27906410 DOI: 10.1039/c6sm01773h] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Artificial macromolecules are well-defined synthetic polymers, with a relatively simple structure as compared to naturally occurring macromolecules. This review focuses on the ion specificities of artifical macromolecules. Ion specificities are influenced by solvent-mediated indirect ion-macromolecule interactions and also by direct ion-macromolecule interactions. In aqueous solutions, the role of water-mediated indirect ion-macromolecule interactions will be discussed. The addition of organic solvents to aqueous solutions significantly changes the ion specificities due to the formation of water-organic solvent complexes. For direct ion-macromolecule interactions, we will discuss specific ion-pairing interactions for charged macromolecules and specific ion-neutral site interactions for uncharged macromolecules. When the medium conditions change from dilute solutions to crowded environments, the ion specificities can be modified by either the volume exclusion effect, the variation of dielectric constant, or the interactions between ions, macromolecules, and crowding agents.
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Affiliation(s)
- Lvdan Liu
- Department of Chemical Physics, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, P. R. China 230026.
| | - Ran Kou
- Department of Chemical Physics, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, P. R. China 230026.
| | - Guangming Liu
- Department of Chemical Physics, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, P. R. China 230026.
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13
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Murdoch TJ, Humphreys BA, Willott JD, Gregory KP, Prescott SW, Nelson A, Wanless EJ, Webber GB. Specific Anion Effects on the Internal Structure of a Poly(N-isopropylacrylamide) Brush. Macromolecules 2016. [DOI: 10.1021/acs.macromol.6b01001] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Timothy J. Murdoch
- Priority
Research Centre for Advanced Particle Processing and Transport, University of Newcastle, Callaghan, NSW 2308, Australia
| | - Ben A. Humphreys
- Priority
Research Centre for Advanced Particle Processing and Transport, University of Newcastle, Callaghan, NSW 2308, Australia
| | - Joshua D. Willott
- Priority
Research Centre for Advanced Particle Processing and Transport, University of Newcastle, Callaghan, NSW 2308, Australia
| | - Kasimir P. Gregory
- Priority
Research Centre for Advanced Particle Processing and Transport, University of Newcastle, Callaghan, NSW 2308, Australia
| | - Stuart W. Prescott
- School
of Chemical Engineering, UNSW Australia, UNSW Sydney, NSW 2052, Australia
| | - Andrew Nelson
- Australian Nuclear
Science and Technology Organisation, Lucas Heights, NSW 2234, Australia
| | - Erica J. Wanless
- Priority
Research Centre for Advanced Particle Processing and Transport, University of Newcastle, Callaghan, NSW 2308, Australia
| | - Grant B. Webber
- Priority
Research Centre for Advanced Particle Processing and Transport, University of Newcastle, Callaghan, NSW 2308, Australia
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14
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Humphreys BA, Willott JD, Murdoch TJ, Webber GB, Wanless EJ. Specific ion modulated thermoresponse of poly(N-isopropylacrylamide) brushes. Phys Chem Chem Phys 2016; 18:6037-46. [PMID: 26840183 DOI: 10.1039/c5cp07468a] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The influence of specific anions on the equilibrium thermoresponse of poly(N-isopropylacrylamide) (pNIPAM) brushes has been studied using in situ ellipsometry, quartz crystal microbalance with dissipation (QCM-D) and static contact angle measurements between 20 and 45 °C in the presence of up to 250 mM acetate and thiocyanate anions in water. The thickness and changes in dissipation exhibited a broad swelling transition spanning approximately 15 °C from collapsed (high temperatures) to swollen conformation (low temperatures) while the brush surface wettability changed over approximately 2 °C. In the presence of the kosmotropic acetate anions, the measured lower critical solution temperature (LCST) by the three techniques was very similar and decreased linearly as a function of ionic strength. Conversely, increasing the concentration of the chaotropic thiocyanate anions raised the LCST of the pNIPAM brushes with variation in the measured LCST between the three techniques increasing with ionic strength. The thickness of the pNIPAM brush was seen to progressively increase with increasing thiocyanate concentration at all temperatures. It is proposed that specific ion binding of the chaotropic thiocyanate anion with pNIPAM amide moieties increases the electrostatic intra- and intermolecular repulsion within and between pNIPAM chains. This allows the brush to begin to swell at higher temperatures and to an overall greater extent.
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Affiliation(s)
- Ben A Humphreys
- Priority Research Centre for Advanced Particle Processing and Transport, University of Newcastle, Callaghan, NSW 2308, Australia.
| | - Joshua D Willott
- Priority Research Centre for Advanced Particle Processing and Transport, University of Newcastle, Callaghan, NSW 2308, Australia.
| | - Timothy J Murdoch
- Priority Research Centre for Advanced Particle Processing and Transport, University of Newcastle, Callaghan, NSW 2308, Australia.
| | - Grant B Webber
- Priority Research Centre for Advanced Particle Processing and Transport, University of Newcastle, Callaghan, NSW 2308, Australia.
| | - Erica J Wanless
- Priority Research Centre for Advanced Particle Processing and Transport, University of Newcastle, Callaghan, NSW 2308, Australia.
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15
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Gao Y, Yang J, Fan H, Ding Y, Ye X. Insight into the effect of methylated urea on the phase transition of aqueous solutions of poly(N
-isopropylacrylamide) by microcalorimetry: Hydrogen bonding and van der Waals interactions. ACTA ACUST UNITED AC 2016. [DOI: 10.1002/polb.24018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Yating Gao
- Department of Chemical Physics; Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China; Hefei Anhui 230026 China
| | - Jinxian Yang
- Department of Chemical Physics; Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China; Hefei Anhui 230026 China
| | - Haiyan Fan
- Department of Chemical Physics; Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China; Hefei Anhui 230026 China
| | - Yanwei Ding
- Department of Chemical Physics; Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China; Hefei Anhui 230026 China
| | - Xiaodong Ye
- Department of Chemical Physics; Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China; Hefei Anhui 230026 China
- CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China; Hefei Anhui 230026 China
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16
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Micciulla S, Michalowsky J, Schroer MA, Holm C, von Klitzing R, Smiatek J. Concentration dependent effects of urea binding to poly(N-isopropylacrylamide) brushes: a combined experimental and numerical study. Phys Chem Chem Phys 2016; 18:5324-35. [DOI: 10.1039/c5cp07544k] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The concentration-dependent binding of urea to PNIPAM influences the chain conformation as a result of the subtle interplay between hydration properties and urea repartition around the polymer surface.
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Affiliation(s)
- Samantha Micciulla
- Stranski-Laboratorium
- Institut für Chemie
- Technische Universität Berlin
- D-10623 Berlin
- Germany
| | - Julian Michalowsky
- Institut für Computerphysik
- Universität Stuttgart
- D-70569 Stuttgart
- Germany
| | - Martin A. Schroer
- Deutsches Elektronen-Synchrotron DESY
- D-22607 Hamburg
- Germany
- The Hamburg Centre for Ultrafast Imaging (CUI)
- D-22761 Hamburg
| | - Christian Holm
- Institut für Computerphysik
- Universität Stuttgart
- D-70569 Stuttgart
- Germany
| | - Regine von Klitzing
- Stranski-Laboratorium
- Institut für Chemie
- Technische Universität Berlin
- D-10623 Berlin
- Germany
| | - Jens Smiatek
- Institut für Computerphysik
- Universität Stuttgart
- D-70569 Stuttgart
- Germany
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17
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Schroer MA, Michalowsky J, Fischer B, Smiatek J, Grübel G. Stabilizing effect of TMAO on globular PNIPAM states: preferential attraction induces preferential hydration. Phys Chem Chem Phys 2016; 18:31459-31470. [DOI: 10.1039/c6cp05991k] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
We study the effect of the organic co-solute trimethylamine N-oxide (TMAO) on the volume phase transition of microgel particles made from poly(N-isopropylacrylamide) (PNIPAM) using dynamic light scattering (DLS) and all-atom molecular dynamics (MD) simulations.
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Affiliation(s)
- Martin A. Schroer
- Deutsches Elektronen-Synchrotron DESY
- 22607 Hamburg
- Germany
- The Hamburg Centre for Ultrafast Imaging (CUI)
- 22761 Hamburg
| | | | - Birgit Fischer
- Institut für Physikalische Chemie
- Universität Hamburg
- 20146 Hamburg
- Germany
| | - Jens Smiatek
- Institut für Computerphysik
- Universität Stuttgart
- 70569 Stuttgart
- Germany
| | - Gerhard Grübel
- Deutsches Elektronen-Synchrotron DESY
- 22607 Hamburg
- Germany
- The Hamburg Centre for Ultrafast Imaging (CUI)
- 22761 Hamburg
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18
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Song W, Liu L, Liu G. Ion specificity of macromolecules in crowded environments. SOFT MATTER 2015; 11:5940-5946. [PMID: 26119620 DOI: 10.1039/c5sm01023c] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Macromolecular crowding plays a significant role in the solubility and stability of biomacromolecules. In this work, the thermo-sensitive poly(N-isopropylacrylamide) (PNIPAM) has been employed as a model system to study the specific ion effects on the solubility of macromolecules in crowded environments of dextran and polyethylene glycol (PEG). Our study demonstrates that crowding agents can interact with either anions or PNIPAM chains. The chaotropic anion SCN(-) interacts with dextran but does not interact with PEG. Both Cl(-) and CH3COO(-) do not interact with dextran and PEG. On the other hand, dextran can interact with PNIPAM as a hydrogen-bond donor, whereas PEG interacts with PNIPAM as a hydrogen-bond acceptor. The salting-in effect exerted by SCN(-) on PNIPAM is weakened in the crowded environment of dextran but is strengthened in the crowded environment of PEG due to the distinct anion-crowder interactions. In parallel, the salting-out effect generated by Cl(-) and CH3COO(-) on PNIPAM is weakened by the crowding of dextran but is strengthened by the crowding of PEG because of the different macromolecule-crowder interactions. Our study reveals that the ion specificity of macromolecules is altered significantly changing from dilute solutions to crowded environments.
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Affiliation(s)
- Wangqin Song
- Department of Chemical Physics, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, P. R. China 230026.
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