Photochromism Behavior of Multilayer Films of PAH/(NaP_5W_(30)/PAH)_n

Multilayer films composed of PAH/(NaP5W30/PAH)n were prepared by LBL self-assembly method,and were characterized by IR,UV.Irradiated with ultraviolet light,the transparent films changed from colorless to blue,and multilayer films of photochromic properties and the mechanism were studied by UV and ESR spectrums.The results showed that [NaP5W30]4-in multilayer film network remained Preyssler structure,and there was strong electrostatic interaction between [NaP5W30]4-and PAH,and parts of [NaP5W30]4-in multilayer films were reduced to [NaP5W30]5-.The results indicated that the multilayer films possessed excellent photochromic properties,a quicker response restoration speed and good reversible repeatability for light.