In situ preparation of polyaniline within neutral, anionic, and cationic superporous cryogel networks as conductive, semi-interpenetrating polymer network cryogel composite systems

Abstract

Polyaniline [p(An)], one of the most known conducting polymers, was prepared within superporus nonionic polyacrylamide [p(AAm)], anionic poly(2-acrylamido-2-methyl-1-propane sulfonic acid sodium salt) [p(AMPS)], and cationic poly(3-acrylamidopropyltrimethyl ammonium chloride) [p(APTMACl)] cryogels. After they were synthesized, washed, and dried, the neutral p(AAm), anionic p(AMPS), and cationic p(APTMACl) cryogels were soaked in an ammonium persulfate/aniline solution (1:1.25 ratio) in 1 M hydrochloric acid for the in situ oxidative polymerization of p(An) with the cryogel matrices as templates or reactors. The prepared p(AAm)/p(An), p(AMPS)/p(An), and p(APTMACl)/p(An) semi-interpenetrating polymer network (semi-IPN) conductive cryogel composites were characterized with scanning electron microscopy (SEM), Fourier transform infrared spectroscopy, and conductivity analysis. The SEM images revealed that the superporus cryogel networks were almost completely filled with p(An) conductive polymers (CPs). Among the cryogel–CP semi-IPNs, we found that p(AAm)/p(An) semi-IPN conductive cryogel composites provided the highest conductivity values of 1.4 × 10−2 ± 4 × 10−4 S/cm; this was a 6.4 × 106 fold increase in the conductivity from the values of 2.2 × 10−9 ± 1 × 10−10 for p(AAm) cryogels. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44137.