Electrically tunable coloration in polymer dispersed liquid crystal films for adaptive camouflage

Abstract

Polymer dispersed liquid crystals (PDLCs), as electrochromic materials, can rapidly undergo reversible switching between scattering and transparent states, showing significant application potential in electro-optic fields. However, traditional PDLC films are limited to simple transition between a scattering state and a transparent state without switchable colors, lacking the potential for application in adaptive camouflage especially in military related items. In this study, chromium trioxide (Cr₂O₃) and an ionic liquid (IL) were incorporated into PDLCs. This enables a color change through redox reactions between the IL and liquid crystal (LC) molecules, with reversible transitions from green to yellow. The modified PDLC films show excellent electrochromic adaptive camouflage performance. By applying a 5 V electric field, the PDLC films can be successfully manipulated to simulate the colors of various terrestrial backgrounds, including the green forests, the yellow and green mountainous regions, the yellow wilderness areas, the white snow, and the yellow deserts. This research provides new insights into the application of PDLC films for switchable color adaptive camouflage, broadening the application scope of PDLCs.