A kinetic–hydrodynamic simulation of microstructure of liquid crystal polymers in plane shear flow

We study the microstructure formation and defects dynamics arising in liquid crystalline polymers (LCPs) in plane shear flow by a inetic–hydrodynamic coupled model. The kinetic model is an extension of the Doi theory with a non-local intermolecular potential, including ranslational diffusion and density variation. LCP molecules are ensured anchoring at the boundary by an additional boundary potential, meanwhile ass conservation of LCPs holds in the whole flow region. Plane Couette flow and Poiseuille flow are studied using the kinetic–hydrodynamic odel and the molecular director is restricted in the shear plane. In plane Couette flow, the numerical results predict seven in-plane flow modes, ncluding four in-plane modes reported by Rey and Tsuji [Macromol. Theory Simul. 7 (1998) 623–639] and three new complicated in-plane modes ith inner defects. Furthermore, some significant scaling properties were verified, such as the thickness of the boundary layer is proportional to olecular length, the tumbling period is proportional to the inverse of shear rate. In plane Poiseuille flow, the micro-morph is quasi-periodic in time hen flow viscosity and molecular elasticity are comparable. Different local states, such as flow-aligning, tumbling or wagging, arise in different ow region. The difference of the local states, or difference of the tumbling rates in near-by regions causes defects and form branch pattern in irector spatial–temporal configuration figure.