Stable free-standing aramid resin film containing vanadium pentoxide and new colour electrochromism of the film by electrodeposition of gold

Vanadium pentoxide (V2O5) was electrodeposited on a poly(p-phenylene tereph talamide) (PPTA)-film coated electrode. The cyclic voltammogram of the film had a reversible redox current peak. The film Nas dark green in the reduce d state and yellow in the oxidized state. To obtain new colour, gold was fu rther electrodeposited on the film. Not only the redox current peak but als o a new redox current shoulder appeared in the cyclic voltammogram of the o btained fil:m, and it exhibited a multicoloured electrochromism: blackish g reen tt dark green H green ct bright red. The Fed colour in the oxidized st ate was first obtained for the V2O5 film. The new redox current shoulder an d the colour were probably due to Au,.V205 partially formed during electrod eposition of the gold. The redox of the AuyV2O5 was accompanied by egress a nd ingress of Li+ ions and the new colour change. (C) 2001 Elsevier Science B.V. All rights reserved.