Temperature-dependent conductive composites: poly(N-isopropylacrylamide-co-N-methylol acrylamide) and carbon black composite films

Abstract

Innovative temperature-dependent conductive composite materials, poly(N-isopropylacrylamide-co-N-methylol acrylamide)/acid-treated carbon black, poly(NIPAAm-co-NMA)/CB, were prepared. The copolymer of NIPAAm and NMA was synthesized via a random redox copolymerization, and the poly(NIPAAm-co-NMA) copolymer showed thermo-responsive properties. Here, NMA performed a thermal crosslinking function in the copolymer. Carbon black was acid-treated for good dispersion in an aqueous solution. Poly(NIPAAm-co-NMA)/CB composites were obtained by blending various amounts of acid-treated CB into the poly(NIPAAm-co-NMA) aqueous solution, and the films were then post-cured for thermal crosslinking. The properties of the conductive poly(NIPAAm-co-NMA)/CB films such as thermal crosslinking performance, surface resistance, and morphology of the crosslinked composites were investigated. This study demonstrated that the poly(NIPAAm-co-NMA)/CB composites exhibited both temperature-dependent electric resistance and reproducible thermally responsive characteristics. The composites can potentially be applied as new electrical temperature sensor materials.