  Van der Waals interactions between flat surfaces in uniaxial anisotropic
media are investigated in the nonretarded limit. The main focus is the effect
of nonzero tilt between the optical axis and the surface normal on the strength
of van der Waals attraction. General expressions for the van der Waals free
energy are derived using the surface mode method and the transfer-matrix
formalism. To facilitate numerical calculations a temperature-dependent
three-band parameterization of the dielectric tensor of the liquid crystal 5CB
is developed. A solid slab immersed in a liquid crystal experiences a van der
Waals torque that aligns the surface normal relative to the optical axis of the
medium. The preferred orientation is different for different materials. Two
solid slabs in close proximity experience a van der Waals attraction that is
strongest for homeotropic alignment of the intervening liquid crystal for all
the materials studied. The results have implications for the stability of
colloids in liquid crystal hosts.
