Electrochromic paper: utility of electrochromes incorporated in paper

Investigation of the electrochemical behaviour of the inorganic electrochromes tungsten oxide, molybdenum oxide, and Prussian blue (PB), each within mashed paper, shows that WO3 and MoO3 are ideal electrochromes to manufacture 'electrochromic paper', but that PB is not a viable electrochrome in this context. The organic electrochromes methyl viologen (MV) and benzyl viologen (BzV) are water-soluble, so were incorporated by pre-soaking but without mashing the paper. The electrochromic images are intense but impermanent. From the adsorptive behaviour of methyl viologen, it is shown that MV adheres via chemisorption, the extent being a function of the type of paper used. (C) 2001 Elsevier Science Ltd. All rights reserved.