MOLECULAR SELF-ASSEMBLY OF CONJUGATED POLYIONS - A NEW PROCESS FOR FABRICATING MULTILAYER THIN-FILM HETEROSTRUCTURES

Heterostructure multilayer thin films comprised of electroactive polym ers such as poly(thiophene acetic acid), sulfonated polyaniline, poly( pyridinium acetylene) and a poly(p-phenylene vinylene) precursor have been successfully fabricated via a process based on the spontaneous se lf-assembly of conjugated polyions on to a substrate. The process invo lves the alternate dipping of a substrate into a dilute solution of a polycation followed by dipping into a dilute solution of a polyanion, with one or both of the polyions being a conjugated polymer. This proc ess can be repeated as many times as desired to build multilayer thin films of conducting polymers in which each layer deposited is only 5-2 0 angstrom in thickness. Since it is a molecular level deposition proc ess, it is possible to build heterostructure thin films with complex m olecular architectures and thicknesses that are controllable at the mo lecular level.