The local environments surrounding dye molecules were studied with use of coumarin dyes in a mesostructured silica-surfactant nanocomposite, which was formed in a porous alumina membrane by a surfactant-templated method and has an average pore diameter of 3.4 nm. Coumarin dyes, such as coumarin 480 (C480), coumarin 343 (C343), and propylamide coumarin 343 (PAC343), were extracted into the silica-surfactant nanocomposite and time-resolved fluorescence spectra of these dyes were examined. C480 and C343 show slow dynamic Stokes shifts and the decay curve can be fitted by a biexponential function. The decay-time constants obtained from the fitting are almost identical for C480 and C343: 0.87 and 7.5 ns for C480, and 0.86 and 7.6 ns for C343. In contrast to these two coumarin dyes, short decay-time constants (0.50 and 4.8 ns) were obtained for PAC343 in the silica-surfactant nanocomposite. These results indicate that the local environments of C480 and C343 are almost identical but different from that of PAC343. By considering the origin of the dynamic Stokes shift and the mesostructure of the silica-surfactant nanocomposite, the location and microenvironment of coumarin dyes within the silica-surfactant nanocomposite are discussed.
Poly(2-methoxyethyl acrylate) (PMEA) shows excellent blood compatibility because of the existence of intermediate water. Various modifications of PMEA by changing its main or side chain's chemical structure allowed tuning of the water content and the blood compatibility of numerous novel polymers. Here, we exploit a possibility of manipulating the surface hydration structure of PMEA by incorporation of small amounts of hydrophobic fluorine groups in MEA polymers using atom-transfer radical polymerization and the (macro) initiator concept. Two kinds of fluorinated MEA polymers with similar molecular weights and the same 5.5 mol % of fluorine content were synthesized using the bromoester of 2,
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