  Partially wetting nematic liquid crystal (NLC) films on substrates are
unstable to dewetting-type instabilities due to destablizing solid/NLC
interaction forces. These instabilities are modified by the nematic nature of
the films, which influences the effective solid/NLC interaction. In this work,
we focus on the influence of imposed substrate anchoring on the instability
development. The analysis is carried out within a long-wave formulation based
on the Leslie-Ericksen description of NLC films. Linear stability analysis of
the resulting equations shows that some features of the instability, such as
emerging wavelengths, may not be influenced by the imposed substrate anchoring.
Going further into the nonlinear regime, considered via large-scale GPU-based
simulations, shows however that nonlinear effects may play an important role,
in particular in the case of strong substrate anchoring anisotropy. Our
simulations show that instability of the film develops in two stages: the first
stage involves formation of ridges that are perpendicular to the local
anchoring direction; and the second involves breakup of these ridges and
formation of drops, whose final distribution is influenced by the anisotropy
imposed by the substrate. Finally, we show that imposing more complex substrate
anisotropy patterns allows us to reach basic understanding of the influence of
substrate-imposed defects in director orientation on the instability evolution.
