Protein-like dynamical transition of hydrated polymer chains

TL;DR

This study demonstrates a protein-like dynamical transition in hydrated polymer chains, specifically Poly(N-isopropylacrylamide), using neutron scattering and simulations, confirming the transition's universality in macromolecules in water.

Contribution

It provides the first direct experimental and computational evidence of a protein-like dynamical transition in linear polymer chains, independent of polymer topology.

Findings

Dynamical transition occurs at about 225 K.

Quantitative agreement between experiments and simulations.

Transition is universal across different macromolecular systems.

Abstract

Combining elastic incoherent neutron scattering experiments at different resolutions with molecular dynamics simulations, we report the observation of a protein-like dynamical transition in linear chains of Poly(N-isopropylacrylamide). We identify the onset of the transition at a temperature $T_d$ of about 225~K. Thanks to a novel global fit procedure, we find quantitative agreement between measured and calculated polymer mean-squared displacements at all temperatures and time resolutions. Our results confirm the generality of the dynamical transition in macromolecular systems in aqueous environments, independently of the internal polymer topology.