| The effect of high ac electric fields upon a lyotropic liquid crystalline polymer solution, poly(n-hexyl isocyanate) in p-xylene, is examined. Rheological studies at concentrations strictly within the isotropic phase domain region indicate that the solutions exhibit an increase in rheological properties proportional to the strength of the field at concentrations well below those exhibiting liquid crystalline behavior, an observation not previously noted within the literature. Morphological studies are performed at concentrations within the isotropic and the biphasic, i.e., exhibiting both isotropic and nematic phases, concentration regimes. The isotropic solutions are shown to exhibit morphological changes that can be analyzed with birefringence measurements via comparison with the optical Kerr effect. The negative birefringence behavior of the isotropic concentrations is also discussed. Within the biphasic structure, the nematic domains are found to deform as a function of both electric field strength and frequency. Surface area, domain volume measurements, and molecular alignment mechanisms are also considered. |
