A series of N-substituted aldonamides has been synthesized. Some of these compounds form a thermotropic lamellar mesophase in which molecules in the trans-configuration are arranged in monolayers stabilized by hydrogen bonding and hydrophobic interactions. X-ray diffraction studies have shown that a molecular arrangement of this type exists in the crystalline solid of N-decylribonamide. The relationship between the mesogenic properties and the molecular structures of these compounds is discussed (with reference to the length, branching and cyclisation of the aldonic residue and of the hydrocarbon chain).
Two 4‐cyano‐4′‐alkoxybiphenyl derivatives (3 COB‐8 COB) have been used as fluorescent micellar probes in four different surfactants (SDS, CTAB, NPh‐EO‐9, and NPh‐EO‐30) the concentration [S] of which varies in a broad range around the CMC. The distribution constant K for the solubilization of the probes between micelles and water and the solubility S in the surfactant are obtained from the absorption spectra after saturation of the sample either by stirring at room temperature or by ultrasonication. CMC values in agreement with those reported in the literature are determined from the curves λmax = f[S]. According to the saturation method, a different type of aggregate is formed below the CMC in the case of 8 COB. The emission spectra demonstrate that the COB derivatives are preferentially solvated in polar environment (polarity > ethanol). The assignment of the observed enhanced line width as compared to homogeneous solutions reveals the existence of several types of sites with different polarities and indicates inhomogeneous locations in the micelle with exchange times slower than about 1 nanosecond. – The results are tentatively interpreted according to the Fromherz's surfactant‐block model of the micelle.
N-substituted polymethacrylamides with mesogenic side chains of formula -(CH3,,-NH-CO-R' where R' is derived from ribose, have been synthetizcd. Thermotropic and lyotropic properties of the monomers, polymers, and copolymers with butyl acrylate have been investigated. 0 1990, HUthig & Wepf Verlag, Basel CCC 0025-1 16X/W/$03.00
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