Study on cyanobiphenyl nematic doped by silver nanoparticles

ABSTRACT

We study the effects of doped (1%wt and 2%wt) silver nanoparticles on material properties of nematic liquid crystal: 4-pentyl-4′-cyanobiphenyl. Using differential scanning calorimetry, electrical and dielectric measurements methods, we show that the doped NPs do not affect the nematic’s phase clearing point, lower the dielectric anisotropy, viscosity, switching-off time, and increase the threshold voltage and elasticity of the nematic. We report that the doped materials temperature behaviour of Frederick’s transition threshold voltage and switching-off time, deviates from the expected behaviour for pristine nematics. To explain this anomalous behaviour, we perform data analysis of the governing Frederick’s transition material parameters of studied samples. We show that the elastic parameter of doped samples is not following the predictions of Maier–Saupe theory, which is valid for conventional nematics. We report that the doped samples temperature behaviour of the elastic parameter follows the predictions of the Gelbart and Ben-Shaul theory.

Graphical Abstract

KEYWORDS:

• Liquid crystal nanocomposites
• liquid crystal material properties
• electro-optics of nematics
• Maier–Saupe theory
• Gelbart–Ben-Shaul theory

Acknowledgements

KKV thanks the College of Arts and Sciences (SIUE) Dean’s office, for providing start-up funds for accomplishing this project. KKV, AD, and BK thank the Department of Physics (SIUE) and the Chair: Prof. Hamad, for overall support. KKV, AD, and BK thank the School of Pharmacy (SIUE), in particularly Prof. McPherson and Prof. Kolling, for overall support and access to the Differential Scanning Calorimeter: (Q2000 from TA instruments). AD and BK are grateful to SIUE Undergraduate Research and Creative Activities (URCA) programme and the Coordinator: Prof. Pawlow, for providing financial support during the accomplishment of the project.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

Research funded by Southern Illinois University-Edwardsville (start-up funds awarded to KV), and SIUE Center of Undergraduate Research and Creative Activities (awarded to AD and BK)