多酸含量对无机/高分子复合薄膜结构及光致变色性能的影响

制备了一系列不同浓度的钨磷酸/聚乙烯醇(PWA/PVA)复合薄膜, 通过红外光谱、原子力显微镜、紫外-可见吸收光谱对复合薄膜的结构和光致变色性能进行了研究. 红外光谱分析结果表明, Keggin结构钨磷酸和聚乙烯醇分子的基本结构在复合薄膜中仍然存在, 钨磷酸分子与高分子底物间存在氢键作用, 形成电荷转移桥. 原子力显微镜(AFM)结果表明复合前后PVA薄膜表面形貌发生了显著变化, 复合膜表面形貌随钨磷酸含量的不同而不同. 在紫外光照射下, 复合薄膜由无色变为蓝色. 复合膜的升色速度和褪色速度均随着钨磷酸含量的增加而加快. 这些结果表明钨磷酸含量对复合膜的微结构存在影响, 从而导致了复合膜具有不同的光致变色性能.

Effect of Polyoxometalates Content on Structure and Photochromism of Inorganic-Polymer Composite Films

A series of phosphotungstic acid (PWA)/poly(vinyl alcohol) (PVA) composite films with differ-ent PWA content have been prepared. The structure and photochromic properties of the composite thin films were studied with Fourier transform infrared spectroscopy (FT-IR),atomic force microscopy (AFM) and ul-traviolet-visible spectra (UV-vis). FT-IR results showed that the Keggin geometry of PWA and PVA were still preserved inside the PWA/PVA composite thin films and a charge-transfer bridge was built between PWA and PVA via hydrogen bond. AFM images indicated that surface topography of the polymer matrix changed after adding PWA and the surface topography of the composite films differed when adding different content PWA. Irradiated with UV light,the transparent films changed from colorless to blue. The photo-chromic efficiency during the coloration process and the velocity during the bleaching process were en-hanced with increasing PWA content. All results indicated that the PWA content affected the structure of composite films,which resulted in the different photochromic properties.