|Budget Amount *help
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2001: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2000: ¥2,700,000 (Direct Cost: ¥2,700,000)
We have prepared mixed micelles of a zwitterionic surfactant having hexadecyl group (C16DAPS) and an ionicsurfactant having octadecyl group (C18TAC1), and measured tracer diffusion coefficients of the micelles, mutual diffusioncoefficients of the surfactants, aggregation numbers of the micelles, and free surfactant-monomer and counter-ionconcentrations. The free C18TA+ ion concentration was found to be very low, and the mutual diffusion coefficientsobserved were found to agree with those calculated from tracer diffusion coefficients of the micelles and counter ions, and the number of counter ions per micelle. Above critical micelle concentrations (CMCs), when surfactantconcentrations were decreased keeping the molar ratio of C18TAC1 to C16DAPS constant, the mutual diffusioncoefficients increased slightly. This concentration dependence is in marked contrast with that for single component ionicsurfactant systems.
We have measured fluorescence decays for pyrene and pyrenesulfonate solubilized in or adsorbed on micelles ofdodecyl-, tetradecyl-, and hexadecyl-trimethylammonium chloride (C12TAC1, C14TAC1, and C16TAC1) in the presence ofquenchers adsorbed on the micellar surface. Quenching reaction rate constants decreased with increasing surfactantchain-length. This decrease is interpreted as due to both the increase in milellar surface area and the decrease in diffusioncoefficients of the fluorophores and quenchers on the micellar surface. We have prepared gold nano-particles protected by the cationic surfactants, CnTACl (n=14, 16, and 18), and ananionic lipid, DMPG Particle shape and size were characterized by the TEM observation. Comparisons of reaction ratesin the protective layers and those in micelles and vesicles are being made.