Comparing Solvophobic and Multivalent Induced Collapse in Polyelectrolyte Brushes

摘要: Coarse-grained molecular dynamics enhanced by free-energy sampling methods is used to examine the roles of solvophobicity and multivalent salts on polyelectrolyte brush collapse. Specifically, we demonstrate that while ostensibly similar, solvophobic collapsed brushes multivalent-ion exhibit distinct mechanistic structural features. Notably, multivalent-induced heterogeneous collapse observed under good solvent polymer backbone conditions, demonstrating mechanism not contingent upon a backbone. Umbrella potential mean-force (PMF) between two individual strands confirms this analysis, revealing starkly different PMFs suggesting role “bridging” as discriminating feature in trivalent Structurally, ions show propensity for nucleating order within brushes, whereas poor-solvent are more...