Review of liquid-crystal phase transitions with quenched random disorder

Recent experimental and theoretical efforts have focused on using liquid-crystal systems as a test bed for understanding the statistical mechanics of quenched random disorder. In particular, the weakly first-order isotropic to nematic (I–N) and the second-order nematic to smectic-A (N–SmA) phase transitions have been intensely studied under two, topologically distinct configurations: (I) confined within a porous media as a function of pore size or (II) perturbed by an imbedded gel as a function of solids density. Thermodynamically singular phase behavior appears to be preserved in an experimentally accessible range of physical parameters governing both I and II. This work reviews the observed transitional behavior of the I–N and N–SmA phase transitions of octylcyanobiphenyl (8CB) as a function of quenched random disorder given by these two configurations. The results to date have revealed a rich variety of effects, confirming some theoretical models, challenging others, all the while displaying ever new phenomena with relevance to a wide range of issues in complex fluids.