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A General Control Strategy to Micropattern Topological Defects in Nematic Liquid Crystals Using Ionically Charged Dielectric Surface
Author(s) -
Sasaki Yuji,
Takahashi Junnosuke,
Yokokawa Shunsuke,
Kikkawa Takuho,
Mikami Ryota,
Orihara Hiroshi
Publication year - 2021
Publication title -
advanced materials interfaces
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.671
H-Index - 65
ISSN - 2196-7350
DOI - 10.1002/admi.202100379
Subject(s) - materials science , liquid crystal , topological defect , dielectric , fabrication , nanotechnology , topology (electrical circuits) , ionic liquid , chemical physics , optoelectronics , condensed matter physics , organic chemistry , medicine , chemistry , physics , alternative medicine , mathematics , pathology , combinatorics , catalysis
Tailoring self‐organized nano/microstructures in soft materials is crucial for exploiting intrinsic functional properties toward emerging applications. Engineered topological defects in liquid crystals are interesting for electro‐optical devices as well as for soft actuators morphing surface. Despite the promising potential, there are currently few bottom‐up methods for positioning a large number of defects periodically over a large area. It is highly challenging to develop essential techniques for achieving high‐throughput fabrication with simple procedure. Using ultraviolet/ozone treatment, herein we present a general and robust strategy to produce the surface that can be a platform for a self‐organized micropattern of topological defects in nematic liquid crystals, irrespective of the chemical structure of compounds including polymerizable monomers. The micropattern formation is controllable by applying area‐selective surface modification, which dramatically improves the fabrication efficiency. By low frequency impedance spectroscopy, the distinctive frequency dependence of the apparent threshold voltage at the micropattern formation is experimentally assigned to a unique reorientational response which occurs when a dielectric surface is charged by ionic additives. This characterization provides crucial guidance in further engineering self‐organized topological defects in liquid crystals.