A novel photochromic complex comprising of Keggin type tungstophosphate acid (PW12) and polyacrylamide (PAM) was prepared. FT-IR results showed that the Keggin geometry of PW12 was still preserved inside the composit...A novel photochromic complex comprising of Keggin type tungstophosphate acid (PW12) and polyacrylamide (PAM) was prepared. FT-IR results showed that the Keggin geometry of PW12 was still preserved inside the composite, and a charge-transfer bridge was built between PW12 and PAM via hydrogen bond. AFM images indicated that surface topography of polymer matrix changed after adding PW12. Under UV irradiation, the film was reduced photochemically to yield a blue species, which was reversible in the present of oxygen in polymeric network.展开更多
A series of photochromic hybrid films were prepared through entrapping Dawson type tungsten heteropolyoxomet-allates (P2W18C626-) and molybdenum heteropolyoxometallate (P2Mo18O626-) into polyacrylamide matrix. FTIR re...A series of photochromic hybrid films were prepared through entrapping Dawson type tungsten heteropolyoxomet-allates (P2W18C626-) and molybdenum heteropolyoxometallate (P2Mo18O626-) into polyacrylamide matrix. FTIR results showed that the Dawson geometry of heteropolyoxometallates is still preserved inside the composites and strong coulombic interaction is built between heteropolyoxometallates and polyacrylamide via hydrogen bonding. Irradiated with ultraviolet light, the transparent films change from colorless to blue and show reversible photochromism. The bleaching process occurs when the films are in contact with air or O2 in the dark. The molybdenum heteropolyoxometallate hybrid film has higher photochromic efficiency and slower bleaching reaction than tungsten heteropolyoxometallate hybrid film. ESR results indicated that polyacrylamide is a hydrogen donor and the photoreduced process is in accordance with the radical mechanism.展开更多
基金This work was supported by the National Natural Science Foundation of China (59932040).
文摘A novel photochromic complex comprising of Keggin type tungstophosphate acid (PW12) and polyacrylamide (PAM) was prepared. FT-IR results showed that the Keggin geometry of PW12 was still preserved inside the composite, and a charge-transfer bridge was built between PW12 and PAM via hydrogen bond. AFM images indicated that surface topography of polymer matrix changed after adding PW12. Under UV irradiation, the film was reduced photochemically to yield a blue species, which was reversible in the present of oxygen in polymeric network.
基金The authors acknowledge the National Natural Science Foundation of China (No. 59932040) for the provision of financial support.
文摘A series of photochromic hybrid films were prepared through entrapping Dawson type tungsten heteropolyoxomet-allates (P2W18C626-) and molybdenum heteropolyoxometallate (P2Mo18O626-) into polyacrylamide matrix. FTIR results showed that the Dawson geometry of heteropolyoxometallates is still preserved inside the composites and strong coulombic interaction is built between heteropolyoxometallates and polyacrylamide via hydrogen bonding. Irradiated with ultraviolet light, the transparent films change from colorless to blue and show reversible photochromism. The bleaching process occurs when the films are in contact with air or O2 in the dark. The molybdenum heteropolyoxometallate hybrid film has higher photochromic efficiency and slower bleaching reaction than tungsten heteropolyoxometallate hybrid film. ESR results indicated that polyacrylamide is a hydrogen donor and the photoreduced process is in accordance with the radical mechanism.
