m-chloroaniline emulsion polymerization, macromolecular chain structure and electrochemical properties

Poly(m-chloroaniline) (PmClAn) was synthesized by emulsion polymerization. The influences of reaction temperature and initiator concentration on polymerizations were studied. It was found that PmClAn with number-average molecular weight of 1.85 × 103 g mol−1 was obtained by the following conditions: 80 °C, [monomer] = 0.187 × 10−3 mol l−1, [sodium lauryl sulfate] = 4.8 × 10−2 mol l−1, [potassium peroxydisulfate] = 5.6 × 10−2 mol l−1, reaction period = 2.0 h. 1H NMR, FTIR, and transmission and scanning microscopy were used for structural characterization of PmClAn. It was shown that the ratio of benzoid to quinoid units in the macromolecular chain was respectively 3:2, and that PmClAn has a typical crystalline monoclinic form. A PmClAn molecular chain configuration was also proposed on the basis of crystallographic data. Cyclic voltammetry experiments revealed the PmClAn membrane electrode electroactivity. This electroactivity increased when the polymer was proton-doped. When Pt particles were electrodeposited onto the polymer membrane electrode, they presented a preferred orientation. Isopropanol oxidation intensities with platinized PmClAn modified electrodes were larger than with a platinized Pt electrode. We also found that oxidation occurred mainly on the Pt particles deposited on the polymer, and that the anodic peak potential changed with polymer and its doping level. These results indicated that the Pt particles interacted with the polymer and that catalytic properties could be observed. © 2002 Society of Chemical Industry