Nematic films at chemically structured surfaces. (30th December 2016)

• Record Type: Journal Article
• Authors: Silvestre, N M; Telo da Gama, M M; Tasinkevych, M
• Is Part Of: Journal of physics. Volume 29:Number 7(2017)
• Publication Date: 2016-12-30
• Subjects: nematic films -- nematic interfaces -- patterned surfaces; Condensed matter -- Periodicals; Matière condensée -- Périodiques; Vaste stoffen; Vloeistoffen; Natuurkunde; Electronic journals; Computer network resources; 530.4105
• DOI: 10.1088/1361-648X/aa4fd6
• Languages: English
• ISSNs: 0953-8984

Abstract

Abstract: We investigate theoretically the morphology of a thin nematic film adsorbed at flat substrate patterned by stripes with alternating aligning properties, normal and tangential respectively. We construct a simple 'exactly-solvable' effective interfacial model where the liquid crystal distortions are accounted for via an effective interface potential. We find that chemically patterned substrates can strongly deform the nematic-air interface. The amplitude of this substrate-induced undulations increases with decreasing average film thickness and with increasing surface pattern pitch. We find a regime where the interfacial deformation may be described in terms of a material-independent universal scaling function. Surprisingly, the predictions of the effective interfacial model agree semi-quantitatively with the results of the numerical solution of a full model based on the Landau–de Gennes theory coupled to a square-gradient phase field free energy functional for a two phase system.