Preparation of porous polyamide films with enhanced electrochromic performance by electrostatic spray deposition

Abstract

Porous polyamide films were prepared by a simple electrostatic spray deposition method for the first time. The polymer solution quickly was dispersed into micron-sized droplets and deposited on the substrate under the electrostatic field forces. With the continue depositing of the droplets and evaporating of the solvent, many voids formed between the droplets to form a porous structure. Thanks to existence of these porous channels, the ion transmission could be effectively increased. Therefore, compared with the film prepared by traditional blade coating, the porous film exhibited a smaller redox potential interval and shorter response time. Introducing of silver nanowires (AgNWs) into the polymer solution wouldn't impede the formation of porous structure, and electrochromic response time for the obtained polyamide/AgNWs film can be effectively improved. The bleaching/coloring time could reach 0.8 s/1.2 s, which is the best record for the polyamide based electrochromic film. These results showed that, electrostatic spraying technology is a promising and efficiently method to prepare polymer film with good electrochromic property. • The organic electrochromic polymer films with rough surface and stacked structure were prepared by electrostatic spraying. • Porous structure films were prepared by electrostatic spraying after introducing AgNWs into the solution. • Films exhibited small redox potential interval, short response time and high coloration efficiency.