Effect of poly(n-isopropyl acrylamide-coitaconic acid) on the chemical polymerization of pyrrole with (NH₄)₂[Ce(NO₃)₆]

The chemical oxidative polymerization of pyrrole (Py) by ceric ammonium nitrate (CAN) in the presence of polyitaconic acid and its copolymers (Polymer) containing 75 and 50mole% N-isopropylacrylamide were investigated. The effects of copolymer composition and addition order of the components on the reaction mechanism were studied by following the absorption spectra of the soluble reaction products between 200 and 1100nm. As to the UV-visible, FTIR and conductivity results of soluble products obtained from Polymer-CAN-Py system, it was assumed that the pyrrole polymerization by chemical oxidation was inhibited in the presence of the water-soluble polyelectrolyte because an important part of ceric ammonium nitrate was consumed to produce radicals on the chains. On the other hand, the role of the copolymers in the case of Py-CAN was mainly to prevent precipitation of polypyrrole. Consequently, the reaction prepared according to the first order of addition of the reactants favour the formation of oligomeric pyrrole, while the second order of addition yields solution of colloidal polypyrrole interacting with polyelectrolytes.