Stimuli-responsive hydrogels based on acrylic acid and acrylamide

Abstract

Hydrogels are three-dimensional polymeric networks that can absorb and retain large quantities of water in relation to their physical size. By incorporating stimuli-responsive units into the gel structure, hydrogels can be actuated by external stimuli such as light[1], temperature[2] and pH[3], among others. In this study pH responsive hydrogels were developed using copolymers of acrylic acid (AA) and acrylamide (Am) in different molar ratios (30:70, 50:50 and 70:30, respectively). In order to turn this pH response into a photo-response, a reversible photo-acid generator, namely spiropyran acrylate (SP-A), was copolymerised in the polymer backbone