Regensburg 2016 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 63: Interfaces and Thin Films II (joint session CPP/DY, organized by CPP)

CPP 63.4: Talk

Friday, March 11, 2016, 10:15–10:30, H51

Photo-manipulation of the surface tension anisotropy at a liquid-crystal/ITO-glass interface — Hajnalka Nadasi, •Alexey Eremin, and Ralf Stannarius — Institute of Experimental Physics, Otto von Guericke University Magdeburg, Universitätsplatz 2, 39016 Magdeburg, Germany

We report direct measurements of the surface energy anisotropy (anchoring energy) at a glass-nematic liquid crystal interface containing a photo-active azo-dendrimeric surfactant. The photoisomerisation at the surface layer drives an anchoring transition from the homogeneous to the planar sate of the liquid crystal. The anchoring energy is measured using the Frederiksz transition as a function of the intensities of the UV and VIS light and is compared with a theoretical model. We also demonstrate optical manipulation of the nematic director field around microshperes and rods dispersed in the liquid crystal. In case of rod-shaped particles, the photo-driven change of the anchoring energy results in a reversible macroscopic rotation of the particles.