A nematic layer with opposite boundary conditions (unidirectional planar and homeotropic) is considered, having strong anchoring at the planar wall. It is known that a periodic deformation of splay-type can intervene between the aperiodic hybrid alignment and undistorted planar state as one decreases the film thickness. This periodic state occurs due to the fact that the energetic cost for a mixed twist-splay can be lower than the surface energetic cost at the homeotropic wall in the case of undistorted planar alignment. Such a situation may also be achieved for nematics which have a bulk elastic isotropy. In this paper, the saddle-splay elastic constant K24 is shown to influence strongly the occurrence of the periodic pattern of splay-type, also in the presence of an external magnetic field normal to the cell plates, and the role of the geometrical anchoring in wedge-shaped cells is discussed.

Saddle-splay and periodic instability in a hybrid aligned nematic layer subjected to a normal magnetic field / Sparavigna, Amelia Carolina; L., Komitov; O. D., Lavrentovich; Strigazzi, Alfredo. - In: JOURNAL DE PHYSIQUE II. - ISSN 1155-4312. - 2:10(1992), pp. 1881-1888. [10.1051/jp2:1992241]

Saddle-splay and periodic instability in a hybrid aligned nematic layer subjected to a normal magnetic field

SPARAVIGNA, Amelia Carolina;STRIGAZZI, Alfredo
1992

Abstract

A nematic layer with opposite boundary conditions (unidirectional planar and homeotropic) is considered, having strong anchoring at the planar wall. It is known that a periodic deformation of splay-type can intervene between the aperiodic hybrid alignment and undistorted planar state as one decreases the film thickness. This periodic state occurs due to the fact that the energetic cost for a mixed twist-splay can be lower than the surface energetic cost at the homeotropic wall in the case of undistorted planar alignment. Such a situation may also be achieved for nematics which have a bulk elastic isotropy. In this paper, the saddle-splay elastic constant K24 is shown to influence strongly the occurrence of the periodic pattern of splay-type, also in the presence of an external magnetic field normal to the cell plates, and the role of the geometrical anchoring in wedge-shaped cells is discussed.
File in questo prodotto:
File Dimensione Formato  
802_UPLOAD.pdf

accesso aperto

Tipologia: 2. Post-print / Author's Accepted Manuscript
Licenza: PUBBLICO - Tutti i diritti riservati
Dimensione 415.07 kB
Formato Adobe PDF
415.07 kB Adobe PDF Visualizza/Apri
Pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11583/1406003
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo