SYNTHESIS OF A NOVEL TYPE OF ELECTROCHEMICALLY DOPED VINYL POLYMER CONTAINING PENDANT TERTHIOPHENE AND ITS ELECTRICAL AND ELECTROCHROMIC PROPERTIES

A novel kind of electrochemically doped poly(5-vinyl-2,2':5',2''-terth iophene) has been prepared by electrochemical doping of poly(5-vinyl-2 ,2':5',2''-terthiophene) and by electrolytic polymerization of 5-vinyl -2,2':5',2''-terthiophene in the presence of tetra-n-butylammonium per chlorate as a supporting electrolyte. The electrochemically doped poly (5-vinyl-2,2':5',2''-terthiophene), obtained as bluish purple lustrous films, is identified as a partially oxidized radical-cation salt with ClO4- as a dopant, having a partially cross-linked structure due to t he coupling reaction of the radical cation of the pendant terthiophene moiety. The polymer with a degree of doping of 45% exhibits a room-te mperature conductivity of 2 x 10(-8) S cm(-1) with an activation energ y of 0.5 eV. The polymer undergoes a reversible clear color change fro m bluish purple to pale yellowish orange and vice versa on electrochem ical dedoping and doping and functions as a novel class of potential e lectrochromic material.