Fluorescent Upconversion In Micelles And NIR-induced Fission Process Of Azobenzene-containing Polymer Vesicles

The interaction between light and material is the basic scientific problem in the research of phtonics material and device. In this dissertation, research was focused on the special phenomenon in the photo-responsive process of assemblies, including the research of fluorescent upconversion in micelles by encapsulating the upconversion molecules into micelles, and the NIR induced fission process of azobenzene-containing polymer vesicles by introducing Fe3O4nanoparticles was also studied. Details are described as below:1. Two fluorescent molecules ZnTCPP and BODIPY-OH were designed and synthesized, the upconversion phenomenon was observed by dissolving them in THF solutions with the molar ratio of1:15followed by removing the oxygen. The relationship between temperature and the fluorescent intensity of BODIPY-OH which was encapsulated into micelles composed of Pluronic F-127was observed, and the method of modulating the volume of micelles via changing the temperature was established. Futhermore, ZnTCPP and BODIPY-OH was encapsulated into micelles composed of Pluronic F-127to forming the upconversion system in micelles, the varaiation trend of fluoresecent versus temperature was the same as that of single BODIPY-OH system, but upconversion was not observed. At last, upconversion in micelles was observed by choosing PdOEP/DPA system which has higher upconversion efficiency.2. Fe3O4nanoparticles capped with oleic acid were encapsulated into vesicles composed of amphiphilic block copolymer PNIPAM-b-PAZO. And the NIR responsive properties of vesicles were achieved by the photothermal effect of Fe3O4nanoparticles. The local temperature was modulated as incident light spot was just1μm. The role of photothermal effect caused by NIR light and photoisomerization of azobenzene unit caused by UV light in a fission process was studied. And photothermal effect was proved as the main cause of the fission of vesicles while photoisomeraization of azobenzene unit would make the fission process easier.