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 sub stituent. The X-ray diffraction patterns showed the presence of a bila yer smectic C mesophase with the mesogenic groups tilted by an angle b eta approximate to 40 degrees with respect to the layer normal. The el ectron density profile rho(z) along the direction normal to the smecti c 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.