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Tripathi K, Garg H, Rajesh R, Vemparala S. The conformational phase diagram of charged polymers in the presence of attractive bridging crowders. J Chem Phys 2023; 159:204903. [PMID: 38010332 DOI: 10.1063/5.0172696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Accepted: 11/05/2023] [Indexed: 11/29/2023] Open
Abstract
Using extensive molecular dynamics simulations, we obtain the conformational phase diagram of a charged polymer in the presence of oppositely charged counterions and neutral attractive crowders for monovalent, divalent, and trivalent counterion valencies. We demonstrate that the charged polymer can exist in three phases: (1) an extended phase for low charge densities and weak polymer-crowder attractive interactions [Charged Extended (CE)]; (2) a collapsed phase for high charge densities and weak polymer-crowder attractive interactions, primarily driven by counterion condensation [Charged Collapsed due to Intra-polymer interactions [(CCI)]; and (3) a collapsed phase for strong polymer-crowder attractive interactions, irrespective of the charge density, driven by crowders acting as bridges or cross-links [Charged Collapsed due to Bridging interactions [(CCB)]. Importantly, simulations reveal that the interaction with crowders can induce collapse, despite the presence of strong repulsive electrostatic interactions, and can replace condensed counterions to facilitate a direct transition from the CCI and CE phases to the CCB phase.
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Affiliation(s)
- Kamal Tripathi
- The Institute of Mathematical Sciences, C.I.T. Campus, Taramani, Chennai 600113, India
- Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094, India
- Univ. Grenoble Alpes, CNRS, Grenoble INP, 3SR, F-38000 Grenoble, France
| | - Hitesh Garg
- The Institute of Mathematical Sciences, C.I.T. Campus, Taramani, Chennai 600113, India
- Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094, India
| | - R Rajesh
- The Institute of Mathematical Sciences, C.I.T. Campus, Taramani, Chennai 600113, India
- Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094, India
| | - Satyavani Vemparala
- The Institute of Mathematical Sciences, C.I.T. Campus, Taramani, Chennai 600113, India
- Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094, India
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Polanowski P, Sikorski A. Coil-globule transition in two-dimensional polymer chains in an explicit solvent. SOFT MATTER 2023; 19:7979-7987. [PMID: 37818732 DOI: 10.1039/d3sm00975k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/13/2023]
Abstract
The structure of two-dimensional polymer chains in a solvent at different temperatures is still far from being fully understood. Computer simulations of high-density macromolecular systems require the use of appropriate algorithms, and therefore the simulations were carried out using the Cooperative Motion Algorithm. The polymer model studied was exactly two-dimensional, coarse-grained and based on a triangular lattice. The theta temperature and temperature of coil-to-globule transition, and critical exponents were determined. The differences between the structure of such a disk and that of a chain in a dense polymer liquid were shown.
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Affiliation(s)
- Piotr Polanowski
- Department of Molecular Physics, Łódź University of Technology, Żeromskiego 116, 90-543 Łódź, Poland
| | - Andrzej Sikorski
- Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland.
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Garg H, Rajesh R, Vemparala S. The conformational phase diagram of neutral polymers in the presence of attractive crowders. J Chem Phys 2023; 158:114903. [PMID: 36948827 DOI: 10.1063/5.0140721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023] Open
Abstract
Extensive coarse-grained molecular dynamics simulations are performed to investigate the conformational phase diagram of a neutral polymer in the presence of attractive crowders. We show that, for low crowder densities, the polymer predominantly shows three phases as a function of both intra-polymer and polymer-crowder interactions: (1) weak intra-polymer and weak polymer-crowder attractive interactions induce extended or coil polymer conformations (phase E), (2) strong intra-polymer and relatively weak polymer-crowder attractive interactions induce collapsed or globular conformations (phase CI), and (3) strong polymer-crowder attractive interactions, regardless of intra-polymer interactions, induce a second collapsed or globular conformation that encloses bridging crowders (phase CB). The detailed phase diagram is obtained by determining the phase boundaries delineating the different phases based on an analysis of the radius of gyration as well as bridging crowders. The dependence of the phase diagram on strength of crowder-crowder attractive interactions and crowder density is clarified. We also show that when the crowder density is increased, a third collapsed phase of the polymer emerges for weak intra-polymer attractive interactions. This crowder density-induced compaction is shown to be enhanced by stronger crowder-crowder attraction and is different from the depletion-induced collapse mechanism, which is primarily driven by repulsive interactions. We also provide a unified explanation of the observed re-entrant swollen/extended conformations of the earlier simulations of weak and strongly self-interacting polymers in terms of crowder-crowder attractive interactions.
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Affiliation(s)
- Hitesh Garg
- The Institute of Mathematical Sciences, C.I.T. Campus, Taramani, Chennai 600113, India
| | - R Rajesh
- The Institute of Mathematical Sciences, C.I.T. Campus, Taramani, Chennai 600113, India
| | - Satyavani Vemparala
- The Institute of Mathematical Sciences, C.I.T. Campus, Taramani, Chennai 600113, India
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Taylor MP, Ye Y, Adhikari SR. Conformation of a flexible polymer in explicit solvent: Accurate solvation potentials for Lennard-Jones chains. J Chem Phys 2015; 143:204901. [DOI: 10.1063/1.4935952] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Mark P. Taylor
- Department of Physics, Hiram College, Hiram, Ohio 44234, USA
| | - Yuting Ye
- Department of Physics, Hiram College, Hiram, Ohio 44234, USA
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Heyda J, Muzdalo A, Dzubiella J. Rationalizing Polymer Swelling and Collapse under Attractive Cosolvent Conditions. Macromolecules 2013. [DOI: 10.1021/ma302320y] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jan Heyda
- Soft Matter
and Functional Materials, Helmholtz-Zentrum Berlin, Hahn-Meitner Platz 1, 14109
Berlin, Germany, and Department of Physics, Humboldt-University Berlin, Newtonstr. 15, 12489 Berlin, Germany
| | - Anja Muzdalo
- Soft Matter
and Functional Materials, Helmholtz-Zentrum Berlin, Hahn-Meitner Platz 1, 14109
Berlin, Germany, and Department of Physics, Humboldt-University Berlin, Newtonstr. 15, 12489 Berlin, Germany
| | - Joachim Dzubiella
- Soft Matter
and Functional Materials, Helmholtz-Zentrum Berlin, Hahn-Meitner Platz 1, 14109
Berlin, Germany, and Department of Physics, Humboldt-University Berlin, Newtonstr. 15, 12489 Berlin, Germany
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