An electrically light-transmittance-switchable film with a low driving voltage based on liquid crystal/polymer composites

ABSTRACT

As a typical class of electrically light-transmittance-switchable (ELTS) composites materials, polymer dispersed liquid crystal (PDLC) films have been widely used in displays, smart windows, light shutters, etc. However, the commercialised PDLC film still requires a comparatively high voltage to maintain its transparent state, leading to huge power consumption and even a potential safety risk. In this regard, we proposed a ‘heat followed UV’ stepwise polymerisation strategy for preparing a kind of ELTS film with a low driving voltage (~20.7 V) through constructing a coexistent system of polymer dispersed and polymer stabilised liquid crystal (PD&SLC). In this new PD&SLC system, vertically orientated polymer networks were formed within LC domains to induce the vertical alignment of LC, thereby reducing the driving voltage. Also, the as-made PD&SLC film exhibited good flexibility due to the high content of polymer. Moreover, the effects of the liquid crystalline polymerisable monomers content on the polymer morphologies as well as the electro-optical properties of the as-made PD&SLC films were elaborately investigated.

Graphical abstract

KEYWORDS:

• Polymer dispersed liquid crystal
• polymer stabilised liquid crystal
• coexistent system
• polymer morphologies
• stepwise polymerisation

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Ministry of Education for Equipment Pre-Research [6141A020222, 6141A020332];National Key R&D Program of China [2018YFB0703704];National Natural Science Foundation of China (NSFC) [51720105002, 51573006, 51573003].