Reconfigurable Large‐Scale Pattern Formation Driven by Topological Defect Separation in Liquid Crystals

Abstract

Large‐scale patterning of topological defects is vital and challenging from both fundamental and technological points of view in anisotropic fluids. However, this is usually difficult because of their unfavorably high‐energy states. Here, a simple but general pathway for topology engineering is presented: processing topological defects and shape large‐scale patterns in materials with liquid crystalline nature. Dragging field is created through flowing materials at liquid–liquid crystal phase transition temperature or designing electric‐field driven temperature gradient. The dragging fields coupled to a dense colony of topological defects with random spatial distribution form nontrivial periodic ordered topological patterns that are energetically unfavorable compared to the uniform ground state, but are stable in the stationary state. Topological polymeric films based on the strategy are also fabricated. The dragging speed and surface interactions are found to be dominant factors in generating and stabilizing the patterns. This strategy endows fluids with regular and large‐scale topological patterns, paving a new way for the development of fluids and gels with spatially modulated topological nature.

Reconfigurable spatially-periodic umbilical defects in nematic liquid crystals enabled by self-organization

“…In contrast to the aforementioned methods of tailoring the substrate surface, there are examples of creating complex structures with a bottom-up approach, that is, forming periodic patterns in the director field. So far, it is reported that pattern formations are driven by electric and magnetic fields [32][33][34][35][36][37], heating [38], and flow, [39], thin films [40,41]. However, functional systems are limited, and most of them lack reproducibility and domain uniformity.…”