Spread monolayers of cellulose derivatives containing side chain carbazole chromophores air investigated, Structural parameters, such as side chain length and the degree of carbazole substitution, are systematically varied. At lower carbazole content, surface pressure-area isotherms exhibit a liquid analogous phase at molecular areas similar to those observed for cellulose alkyl ethers. A characteristic constant pressure plateau is also evident. As the carbazole content is increased, isotherms shift to lower molecular areas, implying the close parallel packing of chromophore units in the monolayers. An increase in carbazole content also provokes an increase in surface pressure, as well as changes in isotherm shape. For monolayers that show an isotherm plateau, the equilibrium transition surface pressure is found to decrease with increasing temperature. Relatively small positive enthalpy and entropy changes are calculated for the transition. These values are consistent with the identification of the phase transition as bilayer formation. Monolayer transfer to solid substrates was attempted for all samples. Transfer ratios close to unity can be achieved by the optimisation of transfer conditions. Because of the differences in isotherm shape, derivatives with higher carbazole content arc transferred at tow surface pressure (5 mN . m(-1)), while (doclecyl), cellulose and samples of lower carbazole content are transferred at 12 mN . m(-1). References: 23
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