  Boundary conditions for a superconducting order parameter at a diffusive
scattering boundary are derived from microscopic theory. The results indicate
that for all but isotropic gap functions the diffusive boundary almost
completely suppresses surface superconductivity in the Ginzburg-Landau regime.
This indicates that in anisotropic superconductors surface superconductivity
can only be observed for surface normals along high symmetry directions where
atomically clean surfaces can be cleaved.
