Ultrafast Electro-Optical Response of Polymer-Dispersed Liquid Crystals with Ferroelectric Nematic Liquid Crystal in Light Transmission to Light Scattering Switching

Abstract

Liquid crystal/polymer composites, the so-called polymer-dispersed liquid crystals (PDLCs), are electro-optical functional materials capable of switching between light-transmitting and light-scattering states upon the application of an electric field on and off, respectively. They are widely used in applications such as smart windows, which can change their transparency in response to an applied voltage. In the electric field-off process, the decay of transmittance in PDLC is caused by the relaxation of liquid crystal molecules to their initial orientation, and the decay response time is generally dependent on the material properties, such as the elastic constant and viscosity of the liquid crystal material. Faster response times are highly desirable for applications in optical modulation devices. In this study, we fabricated PDLCs using a liquid crystal mixture composed of ferroelectric nematic liquid crystal, DIO with spontaneous polarization, and a structurally related compound. The electro-optical response behavior of the PDLCs exhibited an ultra-fast decay response of 0.13 ms when the electric field is switched off, which is 1/100 that of conventional PDLCs using standard liquid-crystal materials. This ultrafast response was attributed to the electrostatic repulsions among liquid crystal domains induced by the spontaneous polarization of the ferroelectric nematic liquid crystals.