Investigation of thermodynamical, electro-optical and dielectric properties of nematic liquid crystals dispersed with low-concentration barium titanate nanoparticles

ABSTRACT

A liquid crystals nanoparticles composite was prepared by dispersing barium titanate nanoparticles (BT-NPs) into a multi-component liquid crystalline material having wide range room temperature nematic phase. The thermodynamic, optical textures, electro-optical and dielectric properties of the composite sample were studied along with pristine materials. Isotropic to nematic phase transition temperature was enhanced for nano-composites as observed from thermodynamic, optical textures and dielectric investigations. Effect of BT-NPs dispersion on various display parameters of nematic liquid crystals, namely, threshold voltage, dielectric anisotropy, DC conductivity and splay elastic constant has been explored. A relaxation mode in kHz frequency range has been observed for pure and nano-composites samples, which varies with temperature and follows Arrhenius behaviour. DC conductivity enhances approximately fivefold for BT-NPs dispersed samples. The host liquid crystalline material has nematic ordering which supports alignment of BT-NPs parallel to the nematic director which consequently improves thermal stability, dielectric and electro-optical parameters of the nano-composite system.

Graphical abstract

KEYWORDS:

• Nanoparticles
• nano-composites
• display parameters
• dielectric anisotropy
• switching properties
• conductivity

Acknowledgments

We express our deep sense of gratitude to The Principal, V.S.S.D. College Kanpur for their encouragement and support. One of us (MBP) thanks Science and Engineering Research Board (SERB) DST, Govt of India for financially supporting vide project no. FTP/PS-60/2008.

Disclosure statement

No potential conflict of interest was reported by the author(s).