The relationships between liquid crystallinity and hydrogen bonding are studied in mixtures containing 4-pentoxybenzoic acid, 5OBA, and five bipyridines, XBiPy, with spacers having different flexibilities, by Fourier transform infrared spectroscopy.

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The non-isothermal kinetic analysis of the isotropic-melt to liquid crystalline phase transition of novel liquid crystalline ionogenic copolymers, LCI, the 10-(4-methoxyazobenzene-4'-oxy)decyl methacrylate]-co-2-(acrylamido-2-methyl-1-propanesulfonic acid)s, 10-MeOAzB/AMPS, copolymers, has been performed based on calorimetric experiments at different cooling rates. A classical nonisothermal crystallisation methodology, based on Avrami's equations, was applied and it has shown that the formation of the mesophases from the isotropic state occurred close to the thermodynamic equilibrium and can be described with high accuracy by using different kinetic parameters. The results evidence the presence of several individual processes in the formation of liquid crystalline phases from the melt and a strong dependence of phase transition rates and activation energies with acid contents. In addition, the decrease in the phase transition rate is related to a decrease in orientational entropy and the final inhibition of the liquid crystal behaviour is ascribed to an exponential increase in the activation energy of the phase transition, promoted by strong acid aggregation. An optimum composition of the 10-MeOAzB/AMPS copolymers to achieve the dual characteristics of LCI (ionogenic and liquid crystalline behaviour) requires acid concentrations capable of promoting structure-forming effects on the LC phases and the evolution of phase separated morphologies. I have submitted a manuscript entitled "A kinetic study of the formation of smectic phases in novel liquid crystal ionogens" for consideration for publication in the European PolymerJournal. The manuscript describes the melt-liquid crystal transition of a set of novel liquid crystal side chain copolymers containing sulfonic acid groups having application potential as anisotropic polymer electrolyte membranes. Due to the relevance of the structure-properties relations in these materials, it is important to describe the successive processes involved in the formation of the mesomorphic templates from the isotropic phase. The study of the nonisothermal calorimetric transition carried out in this paper has proved to be useful to describe the forming role of the acid groups on the stabilisation of the liquid crystal phase.The manuscript contains original material which has not been published nor is being considered for publication elsewhere.I look forward to hearing from you in due course. AbstractThe non-isothermal kinetic analysis of the isotropic-melt to liquid crystalline phase transition of novel liquid crystalline ionogenic copolymers, LCI, the 10-(4-methoxyazobenzene-4'-oxy)decyl methacrylate]-co-2-(acrylamido-2-methyl-1-propanesulfonic acid)s, 10-MeOAzB/AMPS, copolymers, has been performed based on calorimetric experiments at different cooling rates. A classical non-isothermal crystallisation methodology, based on Avrami's equations, was applied and it has shown that the formation of the mesophases from the isotropic state occurred close to the thermodynamic...

A homologous series of linear liquid crystal trimers, the 4,4'-bis[v-(4-methoxyazobenzene-4'-yloxy)alkoxy]azobenzenes, has been synthesized and characterized. The transitional properties of the trimers are compared with those of the corresponding series of dimers, the a,v-bis(4-methoxyazobenzene-4'-oxy)alkanes, and monomers, the 4-methoxy-4'-alkoxyazobenzenes. Characteristically pronounced odd-even effects were seen for the transitional properties of both dimers and trimers on varying the spacer lengths. The clearing temperatures of the trimers were higher than those of the corresponding dimers, but as the length of the flexible spacers was increased this difference became rather small. The ratios of T NI , and DS NI /R for monomer:dimer and dimer:trimer are discussed. These are very similar to reported values for similar materials, suggesting that there may be a rather general relationship between the transitional properties of liquid crystal oligomers as the number of mesogenic units is increased.