STABILITY ANALYSIS OF CATENOIDAL SHAPED LIQUID-CRYSTALLINE POLYMER NETWORKS

The equations of nematic Liquid crystal hydrostatics are used to deter mine the driving forces that cause the breakup of catenoidal shaped li quid crystalline networks during the phase separation of isotropic and nematic phases. The catenoidal shaped liquid crystalline network is a ssumed to be an elastic network embedded in an isotropic matrix. The e lasticity of the network arises from isotropic surface contributions ( interfacial tension) and bulk orientation gradients (Frank elasticity) . For liquid crystalline networks with an orientation structure affine to the catenoidal shape, the theory predicts that under certain param etric conditions capillary instabilities will break-up the network by setting up a viscous flow from the thinner sections of the network tow ard the thicker sections. The stability properties of the liquid cryst alline network are summarized in a two-dimensional phase stability dia gram, given by the ratio of surface to bulk elasticity as a function o f the curvature of the catenoid. Typical parametric conditions for nem atic polymers indicate that the liquid crystalline networks are unstab le, in qualitative agreement with the findings of Nakai et al. (Nakai, A; Wang, W.; Hashimoto, T. Macromolecules 1996, 29, 5288).