Skarabot M, Ravnik M, Zumer S, Tkalec U, Poberaj I, Babic D, Osterman N, Musevic I
J. Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia.
Phys Rev E Stat Nonlin Soft Matter Phys. 2008 Mar;77(3 Pt 1):031705. doi: 10.1103/PhysRevE.77.031705. Epub 2008 Mar 24.
We present experimental and theoretical study of colloidal interactions in quadrupolar nematic liquid crystal colloids, confined to a thin planar nematic cell. Using the laser tweezers, the particles have been positioned in the vicinity of other colloidal particles and their interactions have been determined using particle tracking video microscopy. Several types of interactions have been analyzed: (i) quadrupolar pair interaction, (ii) the interaction of an isolated quadrupole with a quadrupolar chain, and (iii) the interaction of an isolated quadrupolar colloidal particle with a two-dimensional (2D) quadrupolar crystallite. In all cases, the interactions are of the order of several 100k(B)T for 2 microm particles, which gives rise to relatively stable 2D colloidal crystals. The experimental results are compared to the predictions of Landau-de Gennes theory and we find a relatively good qualitative agreement.
我们展示了对限制在薄平面向列型液晶盒中的四极向列型液晶胶体中胶体相互作用的实验和理论研究。使用激光镊子将粒子定位在其他胶体粒子附近，并通过粒子跟踪视频显微镜确定它们的相互作用。分析了几种类型的相互作用：（i）四极对相互作用，（ii）孤立四极与四极链的相互作用，以及（iii）孤立的四极胶体粒子与二维（2D）四极微晶的相互作用。在所有情况下，对于2微米的粒子，相互作用的量级为几百k(B)T，这导致了相对稳定的二维胶体晶体。将实验结果与朗道-德热纳理论的预测进行比较，我们发现了相对较好的定性一致性。
