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Water-Polymer Coupling Induces a Dynamical Transition in Microgels.

ABSTRACT: The long debated protein dynamical transition was recently found also in nonbiological macromolecules, such as poly- N-isopropylacrylamide (PNIPAM) microgels. Here, by using atomistic molecular dynamics simulations, we report a description of the molecular origin of the dynamical transition in these systems. We show that PNIPAM and water dynamics below the dynamical transition temperature T _d are dominated by methyl group rotations and hydrogen bonding, respectively. By comparing with bulk water, we unambiguously identify PNIPAM-water hydrogen bonding as mainly responsible for the occurrence of the transition. The observed phenomenology thus crucially depends on the water-macromolecule coupling, being relevant to a wide class of hydrated systems, independently from the biological function.

SUBMITTER: Tavagnacco L

PROVIDER: S-EPMC6416711 | biostudies-literature | 2019 Feb

REPOSITORIES: biostudies-literature

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Water-Polymer Coupling Induces a Dynamical Transition in Microgels.

Tavagnacco Letizia L Chiessi Ester E Zanatta Marco M Orecchini Andrea A Zaccarelli Emanuela E

The journal of physical chemistry letters 20190212 4

The long debated protein dynamical transition was recently found also in nonbiological macromolecules, such as poly- N-isopropylacrylamide (PNIPAM) microgels. Here, by using atomistic molecular dynamics simulations, we report a description of the molecular origin of the dynamical transition in these systems. We show that PNIPAM and water dynamics below the dynamical transition temperature T <sub>d</sub> are dominated by methyl group rotations and hydrogen bonding, respectively. By comparing with ...[more]

PMID: 30735054

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