The effective interface potential for a superconducting layer

The effective interface potential is derived for a superconducting layer attached to a wall. The expression applies to the neighborhood of a continuous wetting or delocalization transition, which exists for type I superconductors with a negative extrapolation length. From this potential a number of features can be easily derived, such as the locus of the phase transition and the critical exponents. Whereas the order parameter exponent is universal, other exponents, like the susceptibility exponent, are not.