SURFACTANT INDUCED INTERFACIAL ANCHORING TRANSITIONS IN NEMATIC LIQUID CRYSTAL DROPLETS ON GLASS SURFACES
Siddharth Kulkarni () and
Prachi Thareja
Additional contact information
Siddharth Kulkarni: Department of Chemical Engineering, Indian Institute of Technology (IIT), Gandhinagar, Palaj, Gandhinagar-382355, Gujarat, India
Prachi Thareja: Department of Chemical Engineering, Indian Institute of Technology (IIT), Gandhinagar, Palaj, Gandhinagar-382355, Gujarat, India
Surface Review and Letters (SRL), 2017, vol. 24, issue 04, 1-12
Abstract:
The interfacial adsorption of surfactants at planar nematic liquid crystal (NLC)–water interface induces an ordering transition from a tilted to perpendicular anchoring with the increase in surfactant concentration at CN=C∕Ccmc≪1, where Ccmc is the Critical Micelle Concentration of surfactants in water. In this study, we show that depending upon the surfactant structure a tilted to perpendicular NLC anchoring transition is observed at C∕Ccmc≥1 in 5CB droplets of size 50–70μm. Micrometer sized 5CB droplets are deposited on glass surfaces using flow coating of 5CB-in-ethanol solutions. When placed on 5CB drop decorated glass surfaces, the aqueous surfactant solutions of aliphatic chain surfactants (SDS, CTAB and CPBr) at CN<1, result in an optical transition to a bright-cross texture attributed to the tilted anchoring of 5CB molecules at 5CB–water interface. At C∕Ccmc≥1, perpendicular anchoring of 5CB molecules at 5CB–water interface results in a droplet texture with a hedgehog defect. In contrast, aqueous solutions of SDBS lead to 5CB droplets with a bright-cross texture regardless of the surfactant concentration in the aqueous phase. These results indicate that the orientation of 5CB molecules is independent of the nature of the surfactant headgroup. In addition, 5CB droplet decorated OTS treated glass substrates show a hedgehog texture which disappears completely on exposure to organic vapors with the response time-dependent on the polarity of the vapor molecules.
Keywords: Nematic liquid crystals; interfaces; surfaces (search for similar items in EconPapers)
Date: 2017
References: View complete reference list from CitEc
Citations:
Downloads: (external link)
http://www.worldscientific.com/doi/abs/10.1142/S0218625X17500445
Access to full text is restricted to subscribers
Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.
Export reference: BibTeX
RIS (EndNote, ProCite, RefMan)
HTML/Text
Persistent link: https://EconPapers.repec.org/RePEc:wsi:srlxxx:v:24:y:2017:i:04:n:s0218625x17500445
Ordering information: This journal article can be ordered from
DOI: 10.1142/S0218625X17500445
Access Statistics for this article
Surface Review and Letters (SRL) is currently edited by S Y Tong
More articles in Surface Review and Letters (SRL) from World Scientific Publishing Co. Pte. Ltd.
Bibliographic data for series maintained by Tai Tone Lim ().