Fluorescence Studies On Some Macromolecular Problems

In this thesis, first, we investigated the micellization dynamics of poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) (PE10300) by laser-induced temperature jump instrument which was set up by ourselves; Secondly, we used fluorescence resonance energy transfer to investigate the polymer diffusion in poly(butyl methacrylate) latex films using a polymerizable benzophenone derivative as a novel energy transfer acceptor and to study the influence of two low molar mass pluronic surfactants of nearly identical chain length and composition but different microstructure on the polymer diffusion; thirdly, we studied the disstacking process of zinc phthalocyanine by poly(ethylene oxide) by fluorescence quenching and transient absorption. Our main findings are as follows:A pulse of infrared light (1.54 μm wavelength, 4 mJ energy) was generated by stimulated Raman shifting the fundamental emission (1.064 μm) of a Nd:YAG laser, using methane gas filled in two long Raman cells at 40 atm. Temperature jump of ~ 1 °C was induced by exposing a volume of water (～2 mm~2) to the pulse of infrared light. An aqueous solution of ANS and PE10300 was irradiated by an ultraviolet light from a 200-W Mercury lamp and heated by the infrared light. PMT was used to monitor the change of the intensity of the fluorescence or the scattered light which was associated to the micellization of the triblock copolymer PE10300. One relaxation process which could be fit well by a monoexponential equation was observed. And the relaxation time decreased with the increase of the temperature and with the increase of the concentration of PE10300.Two types of latex particles with similar particle size, similar molecular weight and molecular weight distribution of their constituent polymers labeled by the donor phenanthrene or by the acceptor a polymerizable benzophenone were synthesized by seeded semicontinuous emulsion polymerization. We studied the diffusion of PBMA polymers in the latex films and obtained the apparent diffusion coefficient at four different temperatures. From the temperature dependence of the diffusion coefficients, we found effective activation energy for diffusion of E_a = 33.5 ± 2.5 kcal/mol using...