(363a) pH-Driven Swelling of Confined Polymer Brushes

When considering the response of novel materials, it is essential to consider how their environment influences their behavior. Subtle shifts in the composition of a solution, for instance, can strongly affect the properties of solvated molecules and interfaces. Smart materials take advantage of these shifting stimuli to enable targeted effects. These materials often utilize polyelectrolytes, whose properties may be tuned by pH and salt content to allow applications in drug delivery, adhesion, tissue engineering, and coatings, among other uses. Inspired by recent work exploring the pH-dependent response of polyelectrolyte-functionalized nanofiltration membranes, we utilize coarse-grained simulations to examine the role of solution pH and salt content in driving the swelling of polymer brushes in confinement. We find substantial shifts in the titration behavior of confined polymer brushes, resulting in nontrivial charging and swelling properties. We discuss the relevance of these results to generic polymer materials, and specifically to problems applying polyelectrolyte materials to ionic separations.