EFFECT OF CHAIN FLEXIBILITY ON THE NEMATIC-SMECTIC TRANSITION

The theory of nematic-smectic phase transition in the system of unifor m semiflexible chains with hard-core repulsion is presented. Both the general density-functional formalism and the tube-model calculation sh ow that the flexibility of the chains results in a strong first-order transition, in contrast to the common weak-crystallization scenario of the nematic-smectic transition in rigid rods. The calculated spinodal volume fraction of the uniform nematic phase and the period of the mo dulation instability an consistent with recent experimental results. [ S1063-651X(98)15511-3].