title: Interparticle potential and drag coefficient in nematic colloids.
abstract: Magneto-optic tweezers were used for measurements of liquid-crystal-mediated forces between spherical beads with tangential anchoring in thin nematic samples. Repulsive force, which results from the quadrupolar symmetry of defects around the immersed beads, decreases proportionally to 1/x6, with x being the bead separation. The velocity with which the particles are pushed apart also follows the same separation dependence. We thus find the effective drag coefficient gamma(eff) independent of x for surface-to-surface distances as small as 10% of the bead diameter.
authors.affiliation: Department of Physics, University of Ljubljana, Jadranska 19, SI-1000 Ljubljana, Slovenia.
authors.forename: Jurij
authors.initials: J
authors.lastname: Kotar
authors.forename: Mojca
authors.initials: M
authors.lastname: Vilfan
authors.forename: Natan
authors.initials: N
authors.lastname: Osterman
authors.forename: Dusan
authors.initials: D
authors.lastname: Babic
authors.forename: Martin
authors.initials: M
authors.lastname: Copic
authors.forename: Igor
authors.initials: I
authors.lastname: Poberaj