Process for the preparation of a solid precursor material useful for tungsten oxide based electrochromic coatings

摘要

A process for the preparation of a highly stable solid precursor material useful for tungsten oxide based electrochromic coatings comprises:

a) preparing an aqueous solution of sodium tungstate in deionized water;

b) passing the aqueous solution prepared in step a) through a vertical column containing acidic ion exchange resin to give an elute;

c) collecting the elute from step b) directly into a peroxide as colloidal polytungstate sol with a pH not exceeding 2;

d) stirring the mixture obtained in c) for a period ranging between 30 to 120 minutes to form a peroxypolytungstate solution;

e) mixing an organic acid to said peroxypolytungstate solution as obtained in step d) under reflux conditions at a temperature of 55{C for a time period in the range of 1-2 hours to form a peroxypolytungstate acid derivative;

f) converting said peroxypolytungstate acid derivative to a highly stable solid precursor material by fast vacuum drying;