Low Threshold Voltage and Programmable Patterned Polymer-Dispersed Liquid Crystal Smart Windows

Abstract

Polymer-dispersed liquid crystal (PDLC) smart windows hold significant potential for energy-efficient buildings and vehicles, offering a promising pathway toward carbon neutrality. However, their widespread applications are hindered by critical limitations, including high driving voltages and the inability to achieve programmable patterning or multi-region addressable control. To address these challenges, we propose a pre-orientation strategy via low-voltage electric field (5 V, 1 kHz), which optimizes liquid crystal molecular alignment during the phase separation process. Vertically aligned liquid crystal molecules in the polymer network with enlarged pore structures reduce anchoring energy barriers for LC molecular reorientation, causing a 61.2% reduction in threshold voltage (Vth) from 20.6 V to 8.0 V. Crucially, a programmable patterned PDLC film is successfully fabricated by utilizing cost-effective photomasks. Due to the different Vth of the corresponding regions, the patterned PDLC film exhibits stepwise control modes of light transmission: patterned scattering state, patterned transparent state and total transparent state, driven by incremental voltages. Our method can achieve not only energy-efficient tunable patterns for esthetic designs (e.g., logos or images) but also a scalable platform for multi-level optical modulation, which will advance PDLC technology toward low-voltage adaptive smart windows and open avenues for intelligent architectures and broadening their application scenarios.