Molecular Dynamics Simulation of the Influence of Temperature and Salt on the Dynamic Hydration Layer in a Model Polyzwitterionic Polymer PAEDAPS
Jennifer Clark, Vivek Prabhu, Jack F. Douglas
We investigate the hydration of poly(3-[2-(acrylamido)ethyldimethy-lammonio]propanesulfonate) over a range of temperatures in pure water and with the inclusion of 0.1 mol / L NaCl using atomistic molecular dynamics simulation. Drawing on concepts drawn from the field of glass-forming liquids, we use the Debye−Waller parameter () for describing the water mobility gradient around the polybetaine backbone extending to an overall distance ≈ 18 Å. The water mobility in this layer is defined through the mean-square water molecule displacement at a time on the order of water's β-relaxation time. The brush like topology of polybetaines leads to two regions in the dynamic hydration layer. The inner region of ≈ 10.5 Å is explored by pendant group conformational motions, and the outer region of ≈ 7.5 Å represents an extended layer of reduced water mobility relative to bulk water. The dynamic hydration layer extends far beyond the static hydration layer, adjacent to the polymer.
, Prabhu, V.
and Douglas, J.
Molecular Dynamics Simulation of the Influence of Temperature and Salt on the Dynamic Hydration Layer in a Model Polyzwitterionic Polymer PAEDAPS, Journal of Physical Chemistry B, [online], https://doi.org/10.1021/acs.jpcb.3c03654, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=935841
(Accessed December 9, 2023)