The bend elastic constant in a mixture of 4,4 '-n-octyl-cyanobiphenyl and biphenyl

The effect of a rigid, nonpolar and nonmesogenic. solute biphenyl (C6H5-C6H 5) on the divergence of the bend elastic constant (K-33) of 4,4'-n-octyl-cy anobiphenyl (8CB) near the smecticA-nematic transition is reported. The exp onent decreases from about 1.0 to 0.67 as the concentration of biphenyl inc reases. The temperature at which the divergence takes place is about 0.5-1. 0 K hi-her than the transition temperature T-AN. A simple calculation based on Landau theory is presented to explore the C possibilities of the existe nce of a biphenyl induced tricritical point. (C) 2001 Elsevier Science B.V. All rights reserved.