Novel Prussian Blue-Polymer Composite Films Having Electrochromic Properties

Novel Prussian Blue (PB)-polymer composite films were prepared by casting the chloroform solutions of synthetic polymers and the colloidal dispersions of PB protected by surfactants, which had been extracted from an aqueous dispersion of colloidal PB by a chloroform solution containing a cationic surfactant. Among the cationic surfactants examined, n-hexadecyltrimethylammonium chloride was effective to form a stable cast film of PB. The PB-polymer composite films showed electrochromism similar to that of the electrodeposited PB film. The rate of electrochromic response of the PB-polymer composite films can be improved by the addition of LiClO4 to the film. Cyclic voltammometry, energy dispersive X-ray analysis, scanning electron microscopy, and spectroelectrochemical measurement show that the cast composite films contain PB in a soluble form.