Role of BaTiO₃ nanoparticles on electro-optic performance of epoxy-resin-based PDLC devices

ABSTRACT

The physical properties of polymer dispersed liquid crystals (PDLC) can be tuned as per the application requirement by controlling their composition ratio and microstructure. The addition of nanoparticles is the most convenient method to engineer the properties of PDLCs. This paper investigates the effects of barium titanate (BaTiO₃) nanoparticle doping on the morphology, electro-optic, and optical properties of PDLC films. The epoxy resins based PDLC films prepared by polymerisation induced phase separation via heat curing method are doped with BaTiO₃ nanoparticle for the first time. The impact of BaTiO₃ nanoparticle on the microstructure was studied using polarising optical microscopy and scanning electron microscopy. The electro-optic study reveals that the addition of BaTiO₃ nanoparticle results in the reduction of rise time, threshold voltage, saturation voltage and enhancement in the contrast ratio. The doping also results in a decrement of the off-state transmittance curve and an increment in the UV-Visible absorption spectrum. The development of BaTiO₃ doped PDLC films with faster rise time, lower threshold voltage, lower saturation voltage and better contrast ratio will significantly enhance the potential technological applications of PDLC-based devices for smart windows, sensors and flexible devices.

Graphical Abstract

KEYWORDS:

• Liquid crystal
• BaTiO₃ nanoparticle
• PDLC nanocomposites
• driving voltage
• response time
• contrast ratio

Acknowledgments

The authors would like to thank Professor A.K. Ganguli, Department of Chemistry, IIT Delhi for providing nanoparticles and Professor Josemon Jacob, Department of Materials Science and Engineering, IIT Delhi for significant contribution in this research.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the SERB, DST [EMR/2015/001897] and UGC, through Government of India.