Phase-transfer catalysed synthesis of disubstituted poly(phenylene vinylene)

An attempt to synthesize a series of phenyl ring disubstituted poly(o-, m- and p-phenylene vinylene) is reported. In this 'one-pot' reaction, a phase-transfer catalyst was used to promote the extraction of strong base deprotonated bischloromethyl aromatic anions from the aqueous to the organic phase to sustain a nucleophilic substitution reaction with the remaining bischloromethyl monomers. The polymers obtained were characterized for their chemical compositions and physical properties by elemental, i.r. and u.v. spectroscopic, and thermal analyses. The o-substituted polymers were found to have low melting temperatures, good solubilities and high molecular weights, but low yields. The m-substituted monomers, however, produced only non-conjugated poly-m-xylylenes. The p-substituted polymers offered the best combination of yield and physical properties. Films cast from soluble poly(2,5-dibutoxy-p-phenylene vinylene) have electrical volume resistivity in the range 300-500 ohm cm when doped with concentrated sulfuric acid.