Texture Transformation in Nematic Droplets Caused by Ionic Modification of Boundary Conditions

• Published in: Molecular crystals and liquid crystals (Philadelphia, Pa. : 2003) Vol. 489; no. 1; pp. 273/[599] - 279[605]
• Main Authors: Zyryanov, V. Ya, Krakhalev, M. N., Prishchepa, O. O.
• Format: Journal Article
• Language: English
• Published: Taylor & Francis Group 01-01-2008
• Subjects: electrically commanded surfaces; ions; nematic; polymer dispersed liquid crystals; surface anchoring; surfactants
• ISSN: 1542-1406; 1563-5287; 1543-5318
• DOI: 10.1080/15421400802219189

The novel orientational effects caused by the electrically controlled modification of surface anchoring have been considered in liquid crystal droplets. The polymer dispersed liquid crystal films based on nematic 5CB doped with ion-forming cetyl-trimethyl-ammonium-bromide (CTAB) have been tested. Under the action of electric field the surface-active CTA
+
ions in nematic droplets shift towards the cathode. This displacement can alter dramatically the boundary conditions at the part of interface. Two types of ion-induced surface modification are possible: when the anchoring of LC molecules change from the tangential one to the homeotropic and vice-versa. Both variants have been considered as well as the resultant transformation of texture patterns and the proper director configurations within the nematic droplets.