X-RAY-DIFFRACTION STUDY OF INTERMOLECULAR INTERACTIONS IN CHOLESTERYLESTER-SUBSTITUTED CYCLOSILOXANES

The mesophase structure of a series of sixteen cholesterol-based liqui d crystalline materials based on cyclosiloxane backbones is examined. The co-existence of two layer types (full and partial interdigitation of cholesterol mesogens) in the mesophase is examined as a function of ring size, composition, and spacer length. The relative X-ray intensi ties from each layer type are discussed as a function of these variabl es. An increase in the ring size and cholesterol composition, and a de crease in the spacer group all result in more partially interdigitated packing. Molecular modeling calculations performed on the mesogens an d macromolecules examine relative differences in the orientational rel ationships and flexibility of mesogens.