INTERNAL SURFACE, ORIENTATIONAL ORDER, AND DISTRIBUTION OF A POLYMER NETWORK IN A LIQUID-CRYSTAL MATRIX

Optical birefringence of the liquid crystal induced in its isotropic p hase by low concentration polymer networks (1-4% by weight) is used to estimate the internal surface area of the network and its order param eter. The results show conclusively that the polymer networks are fine ly distributed down to the nanometer scale with the orientational orde r parameter being an order of magnitude smaller than that of the nemat ic medium where they are formed. A model structure is presented where molecular fibrils form bundles (relatively rich in polymer) which are responsible for the observed inhomogeneities on the submicrometer scal e.