Physicochemical modulation of liquid crystal anchoring energy via nanopatterned BiTiO/polymer hybrid interfaces

Abstract

High-performance liquid crystal (LC) alignment layers are essential for optimizing the electro-optic properties of advanced display and photonic devices. While conventional rubbing processes are widely used, they face limitations such as physical contact damage and static electricity. In this study, we present a robust non-contact alignment method by transferring one-dimensional nanopatterns onto an ultraviolet-responsive polymer and a BiTiO hybrid film using ultraviolet nanoimprint lithography (UV-NIL). The effects of UV curing time (2, 4, and 6 min) on the morphological stability and surface modification of the films were systematically analyzed to verify their performance as LC alignment layers. Our results demonstrate that LC cells fabricated with BiTiO hybrid thin films cured for 4 min achieved superior homogeneous alignment, as confirmed by polarized optical microscopy (POM) and pretilt angle measurements. Atomic force microscopy (AFM) revealed that the optimal curing time is critical for the formation of well-defined nanopatterns. Furthermore, the developed films exhibited a high average anchoring energy of 1.9 × 10⁻⁴, which is comparable to conventional alignment methods. These findings highlight the potential of nanopatterned hybrid thin films as a highly efficient and stable alternative for next-generation LC alignment applications.