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

ABSTRACT

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.

Graphical Abstract

KEYWORDS:

• PDLCs
• liquid crystal dispersions
• smart windows
• flexible display

Acknowledgments

MIUR, the Italian Ministry for University and Research is acknowledged for financial supports (EX 60%-2018).

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Ministero dell’Istruzione, dell’Università e della Ricerca [EX 60%-2018].