Transient molecular orientation and rheology in flow aligning thermotropic liquid crystalline polymers

Significant progress was made toward conducting in situ structural studies in thermotropic liquid crystalline polymers (LCPs). The confirmation that flow aligning dynamics prevail in at least some main-chain thermotropes calls into question whether the existing body of knowledge accumulated for tumbling lyotropes provides useful insights into the behavior of thermotropic LCPs as well. This paper seeks to address this question by extending such studies to include the transient flow protocols of shear flow inception from a random initial condition, reversal from steady state, nonsteady-state reversal during shear inception, and relaxation upon cessation of shear flow.