Well‐ordered nanostructured organic/inorganic hybrid thin film construction via UV nanoimprint lithography applicable to liquid crystal systems

• Published in: Journal of applied polymer science Vol. 139; no. 26
• Main Authors: Lee, Dong Wook, Won, Jong Hoon, Kim, Dong Hyun, Oh, Jin Young, Kim, Dae‐Hyun, Liu, Yang, Seo, Dae‐Shik
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 10.07.2022; Wiley Subscription Services, Inc
• Subjects: Alignment; Anisotropy; Atomic force microscopy; Contact angle; Indium oxides; Irradiation; liquid crystal alignment; Liquid crystals; Materials science; Microscopy; Nanolithography; nanostructur; Nanostructure; Optical microscopy; organic/inorganic hybrid thin film; Photoelectrons; Polymers; Surface energy; Thin films; ultraviolet nanoimprint lithography; Ultraviolet radiation
• ISSN: 0021-8995; 1097-4628
• DOI: 10.1002/app.52445

In this study, a well‐ordered unidirectional nanostructure was successfully imprinted on a UV curable polymer/indium oxide hybrid film using UV nanoimprint lithography (NIL). The surface morphologies of the hybrid films were analyzed by atomic force microscopy (AFM), and the uniform nanostructure with a period of 820 nm and height of 30 nm was observed on a 6 min UV‐irradiated film by line profile from AFM. The chemical modification of the films according to UV irradiation time was analyzed by X‐ray photoelectron spectroscopy. The nanopatterned hybrid film was applied to the liquid crystal (LC) alignment layer and the polarized optical microscopy and pretilt angle analysis demonstrated the highly uniform and homogeneous LC alignment state. The unidirectional nanostructure guided the LCs orientation and the aligned surface anisotropy which induces the uniform LC alignment. The hybrid film chemical affinity was analyzed by contact angle measurement, and the increased surface energy after UV irradiation contributed to the homogeneous LC alignment. Therefore, various organic/inorganic hybrid films can be used for nanostructure construction via UV NIL, and it has a high potential for application in diverse LC systems. The one‐dimensional nanopattern was successfully transferred to organic/inorganic hybrid thin film via ultra‐violet nanoimprint lithography herein. The well‐ordered nanopattern had the period of 820 nm and height of 30 nm. The unidirectional nanopattern was also applied to the uniform and homogeneous liquid crystal alignment layer with surface anisotropic characteristic.