Elastocapillary interactions on nematic films.
Rod-like colloids distort fluid interfaces and interact by capillarity. We explore this interaction at the free surface of aligned nematic liquid crystal films. Naive comparison of capillary and elastic energies suggests that particle assembly would be determined solely by surface tension. Here, we demonstrate that, under certain circumstances, the capillary and elastic effects are complementary and each plays an important role. Particles assemble end-to-end, as dictated by capillarity, and align along the easy axis of the director field, as dictated by elasticity. On curved fluid interfaces, however, curvature capillary energies can overcome the elastic orientations and drive particle migration along curvature gradients. Domains of dominant interaction and their transition are investigated.
Laboratory for Research on the Structure of Matter, University of Pennsylvania, Philadelphia, PA 19104.
Iris B
IB
Liu
Laboratory for Research on the Structure of Matter, University of Pennsylvania, Philadelphia, PA 19104.
Mohamed A
MA
Gharbi
Laboratory for Research on the Structure of Matter, University of Pennsylvania, Philadelphia, PA 19104.
Victor L
VL
Ngo
Laboratory for Research on the Structure of Matter, University of Pennsylvania, Philadelphia, PA 19104.
Randall D
RD
Kamien
Laboratory for Research on the Structure of Matter, University of Pennsylvania, Philadelphia, PA 19104.
Shu
S
Yang
Laboratory for Research on the Structure of Matter, University of Pennsylvania, Philadelphia, PA 19104 kstebe@seas.upenn.edu.
Kathleen J
KJ
Stebe
2D superstructures; anisotropic particles; curvature; interfacial assembly; topology