Flow-induced birefringence in a lyotropic liquid crystal in the isotropic phase: An order diffusion approach

The flow-induced birefringence produced by the movement of a plate in an isotropic lyotropic liquid crystal phase was theoretically treated as a diffusion problem. A characteristic length $l\sim {10}^{-4}\mathrm{cm},$ which informs about the intermicellar correlation, was experimentally obtained. The diffusion coefficient measured in the middle of the isotropic phase is $D\sim {10}^{-6}{\mathrm{cm}}^2/\mathrm{s}.$ The analysis of the results indicates that $l$ and $D$ increase near the isotropic-to-lamellar phase transition temperatures.