Investigation of the Homologous Series of 4-Propionyl–4′-n-Alkanoyloxyazobenzenes by X-Ray Diffraction

A study of the homologous series of liquid cristalline 4-propionyl-4′-n-alkanoyloxyazobenzenes was performed by x-ray diffraction. Two indipendent parame ters were used, namely the temperature and the paraffinic chain length, in order to obtain some structural in formation. In particular the molecular layer thickness was obtained as a function of the temperature for the different phases and different homologous. A linear de pendence of the molecular layer thickness as a function of chain length was found for the crystalline phase as it was previously observed for the smectic A phase. By comparison of the present data with those of the series 4-acetyl-4′-n-alkanoyloxyazobenzenes, a bilayer molecular organization similar to that of the smectic A phase appears as very probable also for the crystalline phase.