Electrochemical polymerization of alkyltrichlorosilane monomers to form branched Si backbone polymers

An electrochemical method for the synthesis of branched Si backbone polymer s is described. The method offers an attractive alternative for the synthes is of branched silane polymers having general formula Si(RHx)(n) which are of interest as soluble polymer precursors for the formation of SiC. Under t hese mild reaction conditions, the polymerization of alkyltrichlorosilane m onomers is slowed considerably compared to thermal reduction methods, allow ing a manifestation of differences in reactivity of monomers in the series: methyltrichlorosilane, n-butyl-trichlorosilane, and cyclohexyltrichlorosil ane. The different product distributions obtained are attributed to the inf luence of steric effects upon intramolecular cross-linking and intermolecul ar chain propagation reactions. (C) 1999 Elsevier Science Ltd. All rights r eserved.