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Abstract
Aqueous lyotropic liquid crystalline systems of Type I (Δχ > 0), composed of finite cyclindrical micelles, and Type II (Δχ < 0) composed of finite disc shaped micelles have been prepared in thermodynamic equilibrium with the parent mesophases "Hexagonal Hα” and “Lamellar Lχ” respectively. The degree of order profile has been measured for all hydrocarbon segments by substitution of perdeuteriated amphiphiles in the mesophases and the determination of their deuterium quadrupole splittings. The related co-existent phases have degrees of order profile in the chains, which differ by a constant factor in each of the two cases. The order profile is lowered in the nematic liquid crystal because the micelles are finite in size and their symmetry axes can oscillate about the director of the mesophase. An upper limit for the oscillation angle has been estimated. For the case of Type II with finite bilayer disc micelles, the normal to the discs deviates a maximum of 27° from the director. For Type I with finite cylinders the maximum deviation of the cyclinder axes from the director is estimated as 23°. The approximations of these estimates are discussed as well as the viability of the nematic mesophases as models for bilayer and membrane model chemistry.