The synthesis of poly(p-xylylene)s (PPXs) with side chains containing alkyl bromide functionality, and their postpolymer modification, is described. The PPXs were prepared by a diimide hydrogenation of spoly(p-phenylenevinylene)s (PPVs) that were originally synthesized by a Gilch polymerization. The polymer backbone reduction was performed with hydrazine hydrate in toluene at 80 degrees C to provide polymers with the side-chain-containing bromide functionality intact. To demonstrate post-polymer modification of the side chains, the resulting PPX polymers were modified with trimethylamine to form the tetraalkylammonium ion functionality and were evaluated as anion conducting membranes. While PPX homopolymers containing tetralkylammonium ions were completely water-soluble and not able to form valuable films, PPX copolymers containing mixed tetraalkylammonium ions and hydrophobic chains were capable of film formation and alkaline stability. In addition, an in situ cross-linking process that used N,N,N',N'-tetramethyl-1,6-hexanediamine during the tetraalkylammonium formation of brominated PPX polymers was also evaluated and gave reasonable films with conductivities of similar to 10 mS cm(-1).