Title:	Alignment of liquid crystals using Langmuir‒Blodgett films of unsymmetrical bent-core liquid crystals
Authors:	Choudhary, Keerti Gupta, R. K. Gupta Pratibha, R. Sadashiva, B.K. Manjuladevi, V.
Keywords:	Langmuir monolayer Langmuir‒-Blodgett film; Brewster angle microscopy atomic force microscope field emission scanning electron microscope liquid crystals
Issue Date:	Oct-2019
Publisher:	Taylor & Francis
Citation:	Liquid Crystals, 2019, Vol.46, p1494–1504
Abstract:	The properties of the thin films of liquid crystal (LC) molecules can be governed easily by external fields. The anisotropic structure of the LC molecules has a large impact on the electrical and optical properties of the film. The Langmuir monolayer (LM) of LC molecules at the air–water interface is known to exhibit a variety of surface phases which can be transferred onto a solid substrate using the Langmuir‒Blodgett (LB) technique. Here, we have studied the LM and LB films of asymmetrically substituted bent-core LC molecules. The morphology of LB film of the molecules is found to be a controlling parameter for aligning bulk LC in the nematic phase. It was found that the LB films of the bent-core molecules possessing defects favour the planar orientation of nematic LC, whereas the LB films with fewer defects show homeotropic alignment. The defect in LB films may introduce splay or bend distortions in the nematic near the alignment layer which can govern the planar alignment of the bulk LC. The uniform layer of LB film facilitates the molecules of nematic to anchor vertically due to a strong van der Waals interaction between the aliphatic chains leading to a homeotropic alignment.
Description:	Restricted Access
URI:	http://hdl.handle.net/2289/7391
ISSN:	0267-8292 1366-5855 (Online)
Alternative Location:	https://doi.org/10.1080/02678292.2019.1574035
Copyright:	2019 Taylor & Francis
Appears in Collections:	Research Papers (SCM)

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