title: Confinement effect on the interaction between colloidal particles in a nematic liquid crystal: an analytical study.
abstract: Motivated by a recent experimental study on the interaction between colloidal particles in a confined nematic liquid crystal [M. Vilfan, N. Osterman, M. Copic, M. Ravnik, S. Zumer, J. Kotar, D. Babic, and I. Poberaj, Phys. Rev. Lett. 101, 237801 (2008)], we discuss in an analytical manner how the interaction potential U between spherical colloidal particles in a confined nematic cell behaves as a function of the interparticle distance r. We show that the short-range potential follows a power law U(r) approximately r(-5) as expected from the quadrupolar nature of the interaction, while the long-range potential is dominated by an exponential function U(r) approximately sqrt[d/r] exp(-2pir/d), where d is the cell thickness. These two regimes are interchanged at r/d approximately 0.8. This behavior of U(r) is in a good semiquantitative agreement with the experimental finding.
authors.affiliation: Nanotechnology Research Institute, 1-1-1 Umezono, Tsukuba 305-8568, Japan. fukuda.jun-ichi@aist.go.jp
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Fukuda
authors.forename: Slobodan
authors.initials: S
authors.lastname: Zumer