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 p(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.