Effect of polymer concentration on the electro-optical, dielectric and photoluminescence properties of confined ferroelectric liquid crystals composites

ABSTRACT

In this work, the effect of polymer concentration (1%, 3% and 5% wt./wt.) on the physical properties of polymer-stabilised ferroelectric liquid crystal composite is presented. The applied voltage and temperature effects have been investigated on electro-optical and dielectric parameters. The concentration of polymer reduces the spontaneous polarisation up to 34.04% at 5% polymer-stabilised ferroelectric liquid crystal composites. At higher concentration, the rotational viscosity also increased by 26.26% but reduced the dielectric strength by 62.8%. The relaxation frequency shifted towards the higher frequency side from 248.183 to 323.52 Hz. A fluorescence study reveals that the emission peak is observed at a wavelength of 424 nm and concentration quenching is observed with 3% and 5% polymer-stabilised ferroelectric liquid crystal composites. The present work also provides information about the interaction mechanism between polymer and ferroelectric liquid crystal molecules.

GRAPHICAL ABSTRACT

Highlights

• We have prepared polymer-stabilised ferroelectric liquid crystal composites.

• Optical study suggests that the higher concentration (3 wt.% and 5 wt.%) of polymer distorted the helical nature of FLC.

• Dielectric study reveals the shifting of relaxation frequency towards higher frequency side.

• The PL spectroscopy shows the phenomena of concentration quenching at 3 wt.% and 5 wt.% of polymer in FLC.

KEYWORDS:

• Ferroelectric liquid crystals
• polymer
• spontaneous polarisation
• response time
• rotational viscosity

Acknowledgements

The authors gratefully acknowledge the Ministry of Human Resource Development (MHRD) for providing financial assistance as a research fellowship to carry out the research work. The authors would grateful to Dr B R Ambedkar National Institute of Technology in Jalandhar for laboratory facilities. The authors also thankful to Council of Scientific and Industrial Research (CSIR) New Delhi under project Sanction No. 03(1451)/18/EMR-II.

Disclosure statement

No potential conflict of interest was reported by the authors.