  We examine fluctuation-induced (pseudo-Casimir) interactions in nematic
liquid-crystalline films confined between two surfaces, where one of the
surfaces imposes a strong homeotropic anchoring (ensuring a uniform mean
director profile), while the other one is assumed to be a chemically disordered
substrate exhibiting an annealed, random distribution of anchoring energies. We
employ a saddle-point approximation to evaluate the free energy of interaction
mediated between the two surfaces and investigate how the interaction force is
influenced by the presence of disordered surface anchoring energy. It is shown
that the disorder results in a renormalization of the effective surface
anchoring parameter in a way that it leads to quantitative and qualitative
changes (including a change of sign at intermediate inter-surface separations)
in the pseudo-Casimir interaction force when compared with the interaction
force in the absence of disorder.
