Anisotropy induced director refraction inside inversion walls in nematic liquid crystalsReport as inadecuate




Anisotropy induced director refraction inside inversion walls in nematic liquid crystals - Download this document for free, or read online. Document in PDF available to download.



Abstract : We compute the texture of the inversion walls which appear in nematics in a magnetic field. In the isotropic case, where the 3 curvature elastic constants are equal, the Brochard planar description is correct. In the anisotropic general case, we find an unpredicted director rotation around the field, which minimizes the elastic free energy of the wall, by transferring some curvature distortion toward the lowest elastic constant curvature mode. This rotation is calculated to first order in the elastic anisotropy. By symmetry, the planar model remains valid when there is no twist in the wall. This rotation explains the recently observed twist of neutral axes along the inversion walls in lyotropic liquid crystals. In the highly anisotropic case polymeric nematics, the ellipticity of closed loop walls should be twice larger than that predicted.

Keywords : elastic constants free energy nematic liquid crystals induced director refraction inversion walls magnetic field curvature elastic constants Brochard planar description director rotation elastic free energy elastic anisotropy lyotropic liquid crystals polymeric nematics closed loop walls





Author: A. M. Figueiredo Neto Ph. Martinot-Lagarde G. Durand

Source: https://hal.archives-ouvertes.fr/



DOWNLOAD PDF




Related documents