Electrochemical and spectral characteristics of conductive pyrrole-3-phenylthiophene copolymers

Abstract

Summary form only given. Conductive pyrrole(P)-3-phenylthlopbene(3PhT) copolymer films were synthesized through electrochemical copolymerization on Pt and ITO anodes. The amount of 3PhT in copolymers was found to increase with increasing 3PhT content in the electrolyte (P:3PhT=1:10; 1:25; 1:50) and with mounting oxidation potential (1,2 < E/sub ox/, V < 1,6 vs.Ag/AgCl) with a more substantial effect of initial monomer mixture oxidation potential. The P-3PhT copolymers synthesized were identified by means of IR, UV-vis electron spectroscopy and cyclic voltammetry (CVA). It was shown that under the conditions of rising 3PhT content in the copolymer there was bathochromic shift of its long-wave absorption band from PP absorption band maximum (/spl lambda//sub max/=416 nm) to that of a corresponding P3PhT band (/spl lambda//sub max/=475 nm). The CVA of copolymer p-doping shows a copolymer oxidation potential shift to a more positive potential region such that the larger the 3PhT content in copolymer chain the greater the shift. Cations and dicatlons in the resulting copolymers were found to be predominantly located on pyrrole rings of a copolymer chain as attested to by two bands with /spl lambda//sub max/=513 and 676 nm observed in the electrone spectrum of doped copolymer due to P oxidation potential being lower. The potential of the reversible n-doping of copolymers in 0,1 M LiClO/sub 4/-CH/sub 3/CN is virtually their 3PhT content independent. Also, an increasing of 3PhT content in co polymer chain gives an increasing of limiting diffusion current which is evidently relevant to charge being predominantly located thereon.