Photoresponsive polymers can respond to the external photo stimuli by altering their physical and chemical properties reversibly. The films prepared with photoresponsive polymers have promising applications in anti-forgery materials, optically rewritable data storage materials, sensing and biomaterials. Azobenzene is a photoresponsive group which can undergo trans/cis isomerization under UV/vis light and change the properties. A series of redox- and photoresponsive copolymers were synthesized with azobenzene as the photoresponsive moiety. Cyclic voltammetry (CV) and Ultraviolet-visible (UV-vis) absorption showed redox- and photoresponsive properties of the synthesized copolymers in the solution. Their films were prepared and were found to be redox- and photoresponsive. The color of the prepared films could be adjusted by the redox stimulus, while UV-vis absorption properties of the prepared films could be adjusted by changing wavelength of light. Spiropyran is a multiple stimuli responsive chromophore. After UV irradiation, the colorless spiropyran undergoes ring opening isomerization and produces blue color and fluorescent merocyanine state. A series of block copolymers containing spiropyran units were synthesized by ATRP method. The recognizing abilities of copolymer films to metal ions were studied by UV/Vis absorption spectra. The copolymer films showed different colors when exposed to different metal ions. The self-assembly behaviors of amphihilic tri-block copolymers in water were studied by virtue of TEM. It was observed that the block copolymers formed micelle structures, in which the hydrophilic block formed the micelle shell and hydrophobic block formed the micelle core. The photoresponsive behaviors and luminescences of the copolymers in solution were studied by UV/Vis absorption spectra and fluorescent emission spectra. The diameters of the polymer micelles in different temperatures and pH values were investigated by dynamic laser scattering. The polyacrylic acid (PAA) films doped with micelles exhibited intense pink fluorescence as well as photochromic behaviors. Besides, these PAA films showed thermochromism behaviors. And the color of the PAA films changed from red to pink when increasing the temperature until the color faded completely. The mechanism and potential applications of the photoresponsive polymers and films were discussed.

Photoresponsive polymers and films

256th National Meeting (2018)

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