Water-polymer coupling induces a dynamical transition in microgels

Abstract

The long debated protein dynamical transition was recently found also in non-biological 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 Td are dominated by methyl group rotations and hydrogen bonding, respectively. By comparing with bulk water, we unambiguously identify PNIPAM-water hydrogen bonding as the main 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.

References in corpus (4)

• Observation of Fragile-to-Strong Dynamic Crossover in Protein Hydration Water
• On the Molecular Origin of the Cooperative Coil-to-globule Transition of Poly(N-isopropylacrylamide) in Water
• Protein Dynamical Transition in Terahertz Dielectric Response
• Evidence of a low-temperature dynamical transition in concentrated microgels

Cited by in corpus (6)

• Molecular Description of the Coil-to-Globule Transition of Poly(N-isopropylacrylamide) in Water/Ethanol Mixture at Low Alcohol Concentration
• Molecular insights on Poly(N-isoproylacrylamide) coil-to-globule transition induced by pressure
• Thermoresponsivity of poly(N-isopropylacrylamide) microgels in water-trehalose solution and its relation to protein behavior
• Atomic scale investigation of the volume phase transition in concentrated PNIPAM microgels
• Protein-like dynamical transition of hydrated polymer chains
• Phenol release from pNIPAM hydrogels: Scaling Molecular Dynamics simulations with Dynamical Density Functional Theory