Lyotropic Liquid Crystal Ionogels under Large Amplitude Oscillatory Shear (LAOS)

Amphiphilic block copolymers (BCPs) self-assemble in the presence of selective solvents and form different types of micellar structures depending on the composition and temperature. At relatively high concentrations of BCP, micelles form ordered lyotropic liquid crystals (LLCs) structures, also known as mesophases. LLCs usually have a polydomain structure with locally anisotropic ordered domains (grains) that are randomly orientated throughout the sample. In this study, ionogels are prepared from LLCs of poloxamer/ionic liquid/oil. We investigate the macroscopic alignment of the LLC ionogels under large amplitude oscillatory shear (LAOS). We show that the development of the overall orientation of the lamellar microstructure can be followed in situ, using the time progression of the dielectric loss modulus ε"(t) and conductivity of the samples. The evolution of Lissajous curves with alignment duration demonstrates mechanical signals of parallel and perpendicular alignments. The knowledge brought by this work can potentially be used in future research of templating technologies for microelectronics, biomaterials, and separations.