Electrochromic effects from a simple commercial polymer membrane

A simple commercial polyester polymer membrane has been found to exhibit an intense electrochromic effect. Most polymers which undergo electrochromic effects contain either transition metals or extensive conjugated systems. We have found that a simple commercial polyester membrane when coated with gold and polarised to −4 V (versus Ag) in aprotic organic solvents displays an electrochromic colour change from a colourless to an intense red state.