Temperature and Solvent Viscosity Tune the Intermediates During the Collapse of a Polymer

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Auteurs principaux: Majumder, Suman, Christiansen, Henrik, Janke, Wolfhard
Format: Preprint
Publié: 2024
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author Majumder, Suman
Christiansen, Henrik
Janke, Wolfhard
author_facet Majumder, Suman
Christiansen, Henrik
Janke, Wolfhard
contents Dynamics of a polymer chain in solution gets significantly affected by the temperature and the frictional forces arising due to solvent viscosity. Here, using an explicit solvent framework for polymer simulation with the liberty to tune the solvent viscosity, we study the nonequilibrium dynamics of a flexible homopolymer when it is suddenly quenched from an extended coil state in good solvent to poor solvent conditions. Results from our extensive simulations reveal that depending on the temperature $T$ and solvent viscosity, one encounters long-lived sausage-like intermediates following the usual pearl-necklace intermediates. Use of shape factors of polymers allows us to disentangle these two distinct stages of the overall collapse process, and the corresponding relaxation times. The relaxation time $τ_s$ of the sausage stage, which is the rate-limiting stage of the overall collapse process, follows an anti-Arrhenius behavior in the high-$T$ limit, and the Arrhenius behavior in the low-$T$ limit. Furthermore, the variation of $τ_s$ with the solvent viscosity provides evidence of internal friction of the polymer, that modulates the overall collapse significantly, analogous to what is observed for relaxation rates of proteins during their folding. This suggests that the origin of internal friction in proteins is plausibly intrinsic to its polymeric backbone rather than other specifications.
format Preprint
id arxiv_https___arxiv_org_abs_2405_04813
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Temperature and Solvent Viscosity Tune the Intermediates During the Collapse of a Polymer
Majumder, Suman
Christiansen, Henrik
Janke, Wolfhard
Soft Condensed Matter
Statistical Mechanics
Chemical Physics
Computational Physics
Dynamics of a polymer chain in solution gets significantly affected by the temperature and the frictional forces arising due to solvent viscosity. Here, using an explicit solvent framework for polymer simulation with the liberty to tune the solvent viscosity, we study the nonequilibrium dynamics of a flexible homopolymer when it is suddenly quenched from an extended coil state in good solvent to poor solvent conditions. Results from our extensive simulations reveal that depending on the temperature $T$ and solvent viscosity, one encounters long-lived sausage-like intermediates following the usual pearl-necklace intermediates. Use of shape factors of polymers allows us to disentangle these two distinct stages of the overall collapse process, and the corresponding relaxation times. The relaxation time $τ_s$ of the sausage stage, which is the rate-limiting stage of the overall collapse process, follows an anti-Arrhenius behavior in the high-$T$ limit, and the Arrhenius behavior in the low-$T$ limit. Furthermore, the variation of $τ_s$ with the solvent viscosity provides evidence of internal friction of the polymer, that modulates the overall collapse significantly, analogous to what is observed for relaxation rates of proteins during their folding. This suggests that the origin of internal friction in proteins is plausibly intrinsic to its polymeric backbone rather than other specifications.
title Temperature and Solvent Viscosity Tune the Intermediates During the Collapse of a Polymer
topic Soft Condensed Matter
Statistical Mechanics
Chemical Physics
Computational Physics
url https://arxiv.org/abs/2405.04813