The diffusion of molecules through the fractal interface between two "trans
parent" media is considered. Such a surface possesses unique properties-its
volume has a finite value. It is shown that the effective diffusion coeffi
cient is equal to zero. This result does not depend on the properties of th
e media which are on the left or on the right of the surface. (C) 2001 Publ
ished by Elsevier Science B.V.