Specific Problems in LCP Theories

There are three additional specific problems that have to be addressed in any molecular theory for polymer nematics. The first one is a possible effect of the Frank elasticity in these systems. It was shown [3] that the Frank and molecular polymer elasticity for LCEs have well-separated space scales, with their crossover, the characteristic scale I evaluated ash = s/K/G [3]. Here, G 10 dyn/cm is a 

The third problem is the possible effect of stress or external field on isotropic-nematic phase transition. In equilibrium, this phase transition is usually described by the well-known Landau phenomenology or more specifically (however, less reliably because of large fluctuations) by the Maier-Saupe mean field theory [2] (see also Refs [30,31 ]). The assumption that the transition behavior of nematic elastomers is independent of stress was roughly confirmed while testing the LCE theory [3], where the parameters of anisotropy were assumed to be independent of stress. The possible dependences of scalar/tensor order parameter on stress/extemal field have been considered in molecular Doi theory [9, 11] or phenomenological approach by Ericksen [41]. 

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