Defect topologies in nematic liquid crystals

Nov 8

Thursday, November 8, 2012

4:30 pm - 5:30 pm
Fitzpatrick Center Schiciano Auditorium Side A

Presenter

Dr. Martin Schoen

Using isothermal-isobaric Monte Carlo simulations we investigate defect topologies due to a spherical colloidal particle immersed in a nematic liquid crystal. Defects arise because of the competition between the preferential orientation at the colloid's surface and the far-field director $\widehat{\bm{n}}_{0}$. Considering a chemically homogeneous colloid as a special case we observe the well-known surface and saturn ring defect topologies for weak and strong perpendicular anchoring, respectively; for homogeneous, strong parallel anchoring we find a boojum defect topology that has been seen experimentally [see P. Poulin {\em et al.}, Phys. Rev. E {\bf 57}, 626 (1998)] but not in computer simulations. We also consider a heterogeneous, patchy colloid where the liquid-crystal molecules anchor either preferentially planar or perpendicular at the surface of the colloid. For a patchy colloid we observe a boojum-ring defect topology in agreement with recent experimental studies. We also observe two other novel defect topologies that have not been reported thus far either experimentally or theoretically.

Contact

None

More Information