Study on Doping Behaviors of Vinyl Hydrogels with Pendant Terthiophenes

Abstract

The water‐swollen poly(AA3T‐co‐NaSS) and poly(AA3T‐co‐PEG) gels were synthesized by radical copolymerization of the monomer, [(2,2′:5′,2″‐terthiophen‐5‐yl)methyl acrylate] (AA3T), containing pendant terthiophenes as an electron‐conducting material with a soluble monomer, sodium p‐styrenesulfonate (NaSS), or oligo(ethylene glycol) (PEG); their swelling, spectral, and doping behaviors were investigated. The degree of swelling of the poly(AA3T‐co‐PEG) gel was independent of the pH, whereas that of poly(AA3T‐co‐NaSS) gel increases abruptly below pH 3, which suggests self‐doping between the AA3T and NaSS groups. The self‐doping is not suppressed by cross‐linking. Both poly(AA3T‐co‐NaSS) and poly(AA3T‐co‐PEG) gels can be chemically doped with concentrated HCl or HClO4 solution.Concentration dependence of the absorbency of the copolymers and gel.magnified imageConcentration dependence of the absorbency of the copolymers and gel.