Isotropic-nematic interface and wetting in suspensions of colloidal platelets |
| |
Authors: | van der Beek D Reich H van der Schoot P Dijkstra M Schilling T Vink R Schmidt M van Roij R Lekkerkerker H |
| |
Institution: | Van't Hoff Laboratory for Physical and Colloid Chemistry, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands. vdbeek@ccr.jussieu.fr |
| |
Abstract: | We study interfacial phenomena in a colloidal dispersion of sterically stabilized gibbsite platelets, exhibiting coexisting isotropic and nematic phases separated by a sharp horizontal interface. The nematic phase wets a vertical glass wall and polarized light micrographs reveal homeotropic surface anchoring both at the free isotropic-nematic interface and at the wall. On the basis of complete wetting of the wall by the nematic phase, as found in our density functional calculations and computer simulations, we analyze the balance between Frank elasticity and surface anchoring near the contact line. Because of weak surface anchoring, the director field in the capillary rise region is uniform. From the measured rise (6 microm) of the meniscus at the wall we determine the isotropic-nematic surface tension to be 3 nN/m, in quantitative agreement with our theoretical and simulation results. |
| |
Keywords: | |
本文献已被 PubMed 等数据库收录! |
|