Abstract
We have studied the nionolayer phase behavior of various mixtures of dipalmitoylphosphatidylcholine (DPPC) with 4-cyano-4′-n-pentylbiphenyl (5CB) at the air/water interface by means of Langmuir technique and Brew-ster angle microscopy. The phase behavior is compared with the ability of 5CB to anchor homeotropically in liquid crystal cells (LC cells) whose surfaces were covered with DPPC monolayers of various molecular area using Langmuir-Blodgett technique. In the present investigations DPPC cells orient 5CB perfectly homeotropically, if the monolayers were transferred to, the display surfaces as tilted phases. In case of a transferred non-tilted phase thr orientation of bulk 5CB was no more homeotropical. We show that an cssential prerequisite for the homeotropic anchoring is the incorporation of 5CB in the orienting surface monolayer and thus the formation of new phases. Our conclusions are supported by DSC and x-ray experiments on fully hydrated DPPC hulk specimens (bilayer systems) mixed in various concentrations with 5CB.
Published Version
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