Shape of the isotropic-(para)nematic coexistence curve in sheared nanotube suspensions

A geometrical argument is used to account for the exponent of 1/3 describing the isotropic-(para)nematic phase boundary of sheared carbon nanotube dispersions [E. K. Hobbie and D. J. Fry, Phys. Rev. Lett. 97, 036101 (2006)]. Through simplifying assumptions motivated by the effects of concentration and attractive interactions, the behavior is explained by relating the mean strain-induced alignment to the average distance between nanotubes for the scenario of limited anisotropy in non-Brownian suspensions.