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Late stage dynamics of phase separation processes of immiscible binary mixtures containing surfactants (amphiphilic molecules) is investigated by computer simulations on the hybrid model proposed by the present authors [T. Kawakatsu and K. Kawasaki, Physica A 167, 690 (1990)]. With use of this hybrid model, one can investigate large scale phenomena while retaining the intramolecular structures of surfactant molecules. Simulations are performed both for irregular bicontinuous and micellar domain formation processes taking the thermal fluctuation effects into account. In the very late stage, the coarsening of the domain structures is considerably slowed down both for bicontinuous and micellar domain formation processes due to the low interfacial tension of the surfactant-adsorbed interfaces. Scaled scattering structure functions are also calculated, which possess the characteristic features of the experimentally observed scattering functions of microemulsions and polymer blends containing amphiphilic block copolymers. We found that the calculated structure function for the system containing surfactants is different from that for the simple binary mixture without surfactant. Also reported are the important effects of thermal fluctuations on micellar domain structures, where the domain formation is considerably accelerated by the thermal fluctuation. 8200

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SynopsisThe results of the measurement of the far-ultraviolet absorption spectra of L-proline oligomers in water and acetonitrile are summarized as follows. The monomer has an absorption maximum a t 182.5 mp in acetonitrile. The absorption maximum of the dimer is found at 185 mp and a shoulder appears around 200 mp, that is, splitting of the absorption spectrum is observed in the dimer. As the degree of polymeriAation increases, the position of the shoulder shifts toward the wavelength of the absorption maximum of poly-~-proline 11, with an accompanying increase in intensity. We may dmcribe the absorption peak aronnd 203 mp of poly-L-proline I1 as identical with the shoulder with an increased intensity. By measurements of optical rotatory dispersion and circular dichroic spectra, it was also confirmed that the appearance of the helical conformation commences a t the tetramer. When the number of residues is five or greater, the conformation of the helical structure of poly-L-proline I1 seems to be completed.