X-ray Diffraction Study of the Smectic C Mesophase of a Side Chain Polyacrylate Containing a Sulfide Substituted Mesogen

An X-ray study was performed on powder specimen and oriented fibers of a side chain liquid-crystalline polyacrylate containing a sulfide substituent. The X-ray diffraction patterns showed the presence of a bilayer smectic C mesophase with the mesogenic groups tilted by an angle β∽40° with respect to the layer normal. The electron density profile ρ(z) along the direction normal to the smectic layers was calculated by Fourier inversion and the results suggest a minor interdigitation of the aliphatic chains. The positional smectic order parameter was also determined.