Modulation of viscoelasticity and interfacial potential of polyelectrolyte brush by Ion-specific interactions

Polyelectrolyte brushes have drawn increasing attention because their physicochemical properties can be modulated by adjustment of the pH and ion concentration. Here, we report controlled grafting poly acrylic acid containing cysteine side chains onto supported lipid membranes to allow for modulation viscoelasticity as well interfacial potential ion-specific interactions, that is, with cadmium ions. Quartz crystal microbalance dissipation indicated resonance frequency increased decreased concentration increased, attributed dehydration brushes. Systematic variation molecular structure demonstrated coexistence thiol carboxyl moieties is necessary viscoelastic response, suggesting these structural features, common naturally occurring proteins, form complexes Analysis height fluctuation colloidal particles reflection interference contrast microscopy change in polymer brush layer alters curvature effective potential. Intriguingly, found caused calcium ions weak, interaction ion-specific. Polymer alter through changes degree hydration opens new avenues design smart, adaptable surfaces.