Polymer Membranes Dispersed Liquid Crystal (PMDLC): a new electro-optical device

• Published in: Liquid crystals Vol. 46; no. 6; pp. 986 - 993
• Main Authors: De Filpo, Giovanni, Armentano, Katia, Pantuso, Elvira, Mashin, Alexander I., Chidichimo, Giuseppe, Nicoletta, Fiore P.
• Format: Journal Article
• Language: English
• Published: Abingdon Taylor & Francis 03-05-2019; Taylor & Francis Ltd
• Subjects: Crystals; Electric fields; flexible display; Glass substrates; Indium tin oxides; liquid crystal dispersions; Liquid crystals; Magnetron sputtering; Membranes; Morphology; PDLCs; Phase separation; Polymers; smart windows; Substrates; Suction; Tin
• ISSN: 0267-8292; 1366-5855
• DOI: 10.1080/02678292.2019.1566506

Polymer Dispersed Liquid Crystals (PDLCs) are liquid crystal dispersions in a polymer matrix, which look like opaque in their OFF state, when no electric field is applied, and transparent in their ON state. They are generally obtained by a phase separation process, such as Thermal, Solvent- and Polymerization-Induced Phase Separation (TIPS, SIPS and PIPS, respectively), between two transparent conductive glass substrates. In this paper, a new electro-optical device, formed by a porous polymer membrane imbibed with liquid crystal by capillary suction, is presented (Polymer Membranes Dispersed Liquid Crystals, PMDLC). Polymer membrane surfaces were made conductive before liquid crystal loading by magnetron sputtering of a thin layer of conductive indium tin oxide. The morphology and the electro-optical response of these devices were investigated and the observed transmittances and relaxation times were found to be similar to those of conventional PDLCs. In addition, PMDLCs showed interesting flexibility as no solid conductive substrate is required and economic convenience as there is no loss of liquid crystal in the polymer matrix.