Environmentally sensitive, quickly responding microgels with lattice channels filled with polyaniline.

A conducting microcomposite composed of cross-linked poly(N-isopropylacrylamide) (pNIPA) and polyaniline (PANI) was synthesized. First, pNIPA gel microcapsules were prepared via surfactant-free emulsion polymerization (SFEP). Then by soaking the gel with a solution of an oxidizing agent (sodium persulfate) and placing it in a solution of aniline in nitrobenzene the conducting polymer was formed in pNIPA. The structure, morphology, swelling behavior and polyaniline oxidation state in the composite were investigated using SEM, TEM, DLS and Raman spectroscopy. The new microcomposite consists of micro-spheres, undergoes rapid volume phase transition and is electroactive. A result of the transition from the swollen to the collapsed state is a strong enhancement of the voltammetric peaks of polyaniline.