Isotropic-to-nematic transition in liquid-crystalline heteropolymers: II. Side-chain liquid-crystalline polymers

We apply a density functional approach for arbitrary branched liquid-crystalline (LC) heteropolymers consisting of elongated rigid rods coupled through elastic joints developed in a companion paper (Wessels and Mulder 2006 J. Phys. Condens. Matter. 18 9335) to a model for side-chain liquid-crystalline polymers. In this model mesogenic units are coupled through finite-length spacers to a linear backbone polymer. The stereochemical constraints imposed at the connection between spacer and backbone are explicitly modelled. Using a bifurcation analysis, analytical results are obtained for the spinodal density of the I-N transition and the variation of the degree of ordering over the various molecular parts at the instability as a function of the model parameters. We also determine the location of the crossover between oblate and prolate backbone conformations in the nematic phase.