Structural investigations of liquid-crystalline ethylcellulose

Abstract

Solutions of ethylcellulose (EC) in acrylic acid (AA) form a mesomorphic phase with cholesteric nature in a limited range of concentrations and temperatures. Detailed phase behavior was investigated by optical techniques including polarized light microscopy, refractive index measurements, and spectrophotometry. Structural characterization was also performed for two kinds of solids prepared from the EC/AA liquid crystal: A polymer composite (EC/PAA) obtained by polymerizing the solvent AA and an EC film obtained by quiescently casting from the solution. Both solids possess optically anisotropic organization which comes from a mesomorphic state in the starting sample. It is shown by electron microscopy that there are many round particles 0.1 to 0.3 μm in the EC/PAA composite, while in the EC cast film well-developed lamellar textures are formed by regular coalescence of round particles. Such morphological features are discussed in relation to the liquid crystalline structure in the initial solution. © 1985 The Society of Polymer Science, Japan.