Preparation of PAA/WO₃ composite films with enhanced electrochromism via layer-by-layer method

The polyacrylic acid/tungsten oxide (PAA/WO₃) composite films with good electrochromic properties have been prepared by a layer-by-layer method. The porous PAA layers were used as a template for the deposition of WO₃, and finally, the composite film showed a network structure with high porosity. The electrochromic performance of the PAA/WO₃ composite film was investigated by means of cyclic voltammogram (CV), chronoamperometry (CA), and transmittance measurements. The PAA/WO₃ film also exhibited a remarkable electrochromism ability with the reversible color change from transparent colorless to dark blue and the transmittance change from 83% to 24% at 620 nm. This research provided a cost-effective approach for the preparation of PAA/WO₃ composite films with controllable microstructure and good electrochromic property.