In situ analysis of the defect texture in liquid crystal polymer solutions under shear

A combination of two in situ small-angle scattering techniques are employed to compare the texture and molecular order in flowing LCPs that exhibit constant viscosities (region II) and shear thinning (region I) at low shear rates. The microstructure is characterized by an overall molecular orientation S_eff, a texture correlation length a_c, and an aspect ratio a_r. Results indicate that in region I the texture has a high density of defects and a low overall molecular order, with shear primarily acting to distort the texture. In region II the texture is distorted in the shear direction and the overall molecular orientation is higher, while the primary influence of shear is to refine texture size. The critical Ericksen stress balance is also tested experimentally.