Nematic liquid crystal flow in microchannels with patterned anchoring

Abstract

Non-Newtonian microfluidics play a crucial role in modern industrial and technological advancements, and in biological phenomena. We report how local variations in the alignment at the boundary of nematic liquid crystals (LCs) govern their flow characteristics under pressure-driven microfluidic conditions. Specifically, we micropatterned the LC anchoring conditions using a photocleavable self-assembled monolayers and investigated the resulting flow characteristics through measurement of flow resistances, and spatial variations in LC director fields as a function of the microfluidic flow. Combined experimental measurements and computational simulations showed that patterned anchoring induces pronounced coupling between flow and molecular alignment, leading to spatially heterogeneous flow regimes revealing backflow mechanisms, hysteresis, pattern-dependent, and rich topological structures. These findings establish a framework for controlling soft anisotropic fluids through interfacial patterning, offering new opportunities for adaptive and reconfigurable microfluidic systems. Nematic liquid crystals offer a way to explore anisotropic fluid dynamics, but are typically confined to uniform boundaries. Combining experiments and simulations, the authors show that patterning anchoring conditions with photocleavable monolayers induces strong flow-alignment coupling, revealing heterogeneous flow regimes.