Microfluidics of nematic mesophases, by Uroš Tkalec

Uroš Tkalec, PhD, Assistant Professor of Physics, presents Microfluidics of nematic mesophases.

“Flow of anisotropic fluids is inherently complex due to the coupling between the orientational order and the imposed shear flow. Experiments carried out with nematic liquid crystals at a microscale reveal strong influence of surface alignment, elasticity, and external fields on equilibrium and dynamic structures. Microfluidics provides a convenient platform to tune the competing parameters, and to explore the resulting topological states and structural transitions among them. I will present how different orientational structures in pressure-driven nematics can coexist and get stabilized in precisely engineered microflows by simultaneous use of laser tweezers. I will also discuss the mechanisms underlaying achiral-to-chiral transition and the dynamics of flow-aligned nematic domains under uniform and oscillatory flow. The findings could find use in out-of-equilibrium lyotropic liquid crystals and active nematics where additional dynamic response is expected due to density- and activity-dependence of elastic properties.”