Electrosynthesis and characterisation of poly(2-methoxyaniline-5-sulfonic acid)-effect of pH control

The effect of solution pH on the oxidation of 2-methoxyaniline-5-sulfonic a cid (MAS) to form a water-soluble polymer has been investigated. By control of solution pH during polymerisation it was found that both monomer conver sion and poly(2-methoxy-5-aniline sulfonate) (PMAS) molecular weight were s ignificantly increased. The electrochemically synthesised PMAS has one sulf onate group attached to each benzene ring along the polymer chain, making t his polymer highly soluble in water (30% w/w) and easy to process. The poly mer has a DC conductivity of ca. 0.01 S/cm. Gel permeation chromatography a nalysis indicated the polymer has a bimodal molecular weight distribution, consisting of a high molecular weight fraction (with average molecular weig ht similar to 15,000) and a low molecular weight fraction (with molecular w eight similar to 2200). (C) 2000 Elsevier Science S.A. All rights reserved.