Ferroelectric polymer‐modified alignment layers for tunable electro‐optical dynamics in nematic liquid crystals

Abstract

The performance of nematic liquid crystal devices is critically governed by the properties of the alignment layer, which control molecular orientation, surface anchoring, dielectric behavior, and electro‐optical response. In this work, homogeneous polyimide alignment layers were modified by incorporating poly[(vinylidene fluoride)‐ co ‐trifluoroethylene] (P(VDF‐TrFE)) to tune the electro‐optical characteristics of the nematic liquid crystal ZLI‐2976. Alignment layers containing different P(VDF‐TrFE) concentrations (1, 3, and 5 wt%) were fabricated and systematically investigated in terms of pretilt angle, dielectric permittivity, threshold and driving voltages, and response time. The results reveal a pronounced concentration‐dependent behavior, with 1 wt% P(VDF‐TrFE) exhibiting the optimum performance, characterized by reduced threshold and driving voltages, faster relaxation dynamics, and enhanced dielectric permittivity. These improvements are attributed to favorable modifications at the liquid crystal–alignment layer interface, consistent with enhanced surface anchoring and interfacial polarization. At higher polymer concentrations, non‐uniform polymer distribution and aggregation are believed to reduce the effectiveness of liquid crystal alignment, leading to increased dielectric loss and slower electro‐optical response. This study demonstrates that the controlled incorporation of P(VDF‐TrFE) into polyimide alignment layers provides an effective strategy for tailoring the electro‐optical properties of nematic liquid crystal devices and offers useful design guidelines for the development of low‐voltage, fast‐switching liquid‐crystal‐based photonic applications. © 2026 Society of Chemical Industry.