  We present an experimental study of the surface effects (interactions with
the container walls) during the nucleation and growth of smectic B crystals
from the nematic in free growth and directional solidification of a mesogenic
molecule ($C_4H_9-(C_6H_{10})_2CN$) called CCH4 in thin (of thickness in the 10
$\mu$m range) samples. We follow the dynamics of the system in real time with a
polarizing microscope. The inner surfaces of the glass-plate samples are coated
with polymeric films, either rubbed polyimid (PI) films or monooriented
poly(tetrafluoroethylene) (PTFE) films deposited by friction at high
temperature. The orientation of the nematic and the smectic B is planar. In
PI-coated samples, the orientation effect of SmB crystals is mediated by the
nematic, whereas, in PTFE-coated samples, it results from a homoepitaxy
phenomenon occurring for two degenerate orientations. A recrystallization
phenomenon partly destroys the initial distribution of crystal orientations. In
directional solidification of polycrystals in PTFE-coated samples, a particular
dynamics of faceted grain boundary grooves is at the origin of a dynamical
mechanism of grain selection. Surface effects also are responsible for the
nucleation of misoriented terraces on facets and the generation of lattice
defects in the solid.
