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

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.

Automated summary

The research successfully prepared porous polyamide films using electrostatic spray deposition method for the first time, which improved ion transmission rate by forming porous structure. Introducing silver nanowires also effectively improved the electrochromic response time of the film, resulting in better electrochromic properties.