Phase engineering for enhanced electrochromism in conjugated polymers

Development of nanostructured blends of electrochromic polymers formed by self-assembly is reported. We have prepared blends of a polythiophene derivative, poly(3,4-ethylenedioxythiophene) and polypyrrole, combining optical and electrochemical properties of the two polymers. The route towards these blends is based on self-assembly of the former polymer into a hydrogel, and subsequent electrochemical polymerisation of the latter using the conducting hydrogel matrix as a template. When used as electrodes, these materials show very fast electrochromic response. The route used in the present work is generic and may be extended to other polymers.