Polymer Dispersed Liquid Crystal Smart Film Technologies: Overview

Abstract

Liquid crystal (LC)-based research and its technological output vary from daily-use personal electronics and flat panels to switchable optical devices such as sensors. Optical and dielectric anisotropy is a key attribute of LCs, imparting functionality and broadening the scope of smart film systems to such products. Among LC smart films, the polymer dispersed liquid crystal (PDLC) smart film depicts an electro-optical (EO) composite sandwiched by transparent conductive oxide electrode-coated polyethylene terephthalate (PET) films. LC orientation and optical transparency in the composite are readily tuned by altering the electric field. The competitiveness of such PDLC devices reflects its favorable response time, energy conservation potential, and manufacturing convenience, all attributes that are readily endorsed by smart home appliances and areas of architecture and the automotive industry. In response to unrelenting market demands, sustainable, energy-efficient, and “greener” PDLC variants have appeared. Particularly worthy of mention are systems featuring transparency at zero field (reverse-mode). Others boast very high energy efficiencies (%80). In this chapter, the science and technology of PDLC, reverse-mode PDLC, and related LC smart films will be reviewed with a highlight on fabrication methods and operating principles. Market potential and research prospects compared to non-LC smart film technologies will also be touched upon.