Reversible functionalization of nanostructured polymer surfaces via stimuli-responsive interpolymer complexes

This manuscript describes the formation of spherical nanostructures on surfaces by interfacial migration of amphiphilic block copolymer micelles. The micelles are formed by macrophase separation of a polymer blend composed of polystyrene-b-poly(acrylic acid) (PS-b-PAA) block copolymers and a high molecular weight polystyrene matrix. The micelles formed in bulk are able to migrate towards the interface upon water vapor annealing, thus forming spherical nanodomains with the carboxylic groups of PAA exposed to the polymer/humid air interface. We explored herein the reversible modification of the PAA nanodomains by complexation with three different polymers, i.e. poly(N-vinylpyrrolidone) (PVP), poly(N-isopropylacrylamide) (PNiPAm) and poly(N-tert-butylacrylamide) (PNtBAm) via hydrogen bond interactions. Whereas the first two polymer complexes, are disrupted by changing the environmental pH in aqueous solution, the third polymer employed is able to form and disrupt the complexes by changing the solvent from either 1- or 2-propanol to methanol.