X-ray Diffraction Studies on Solid and Mesomorphic Phases of Four Members of Alkoxy-Cyanobiphenyls

Abstract

X-ray diffraction studies of four alkoxy cyanobiphenyls (alkyl = nonyl, decyl, undecyl and dodecyl) have been undertaken to determine orientational order parameters, layer thickness, packing fraction and coefficients of HJL type potential. All these values show some odd-even effect with the number of chain carbon atoms. Powder X-ray patterns from these compounds in solid phase have also been indexed satisfactorily. Orientational order parameters have been fitted to those calculated from McMillan's theory by varying the parameters a and σ.

Key Words:

• Mesogens
• order parameters
• cyanobiphenyl
• X-ray diffraction
• packing fraction
• layer thickness