Electrically conducting polymers have been prepared from pyrrole by electrodeposition through two types of isoporous membranes. When pyrrole is polymerized through isoporous polycarbonate membranes, with the polycarbonate subsequently removed with chloroform, a relatively low density of short filaments is produced. Membranes of large pore diameter gave few, rough filaments, but as the pore size decreased the number of filaments increased and their walls were much smoother. A method in which the filaments are contiguous with a supporting sheet is described. When honeycomb structured gamma-alumina membrane is employed, a quite different product is possible. A very high density polymer of long, hexagonal filaments appear after the gamma-alumina is leached using sodium hydroxide. This material has a very high surface area and structural regularity. It has potential as an electrode material in which switching from conducting to non-conducting states could be efficiently achieved by rapid expulsion of counter-ion.
