FLUCTUATION PROPERTIES OF INTERFACES AND MEMBRANES BOUNDED BY SELF-AFFINE SURFACES

In this work we study fluctuation properties of fluid interfaces/membr anes bounded by a rough self-affine surface. We find that the fractal character of the substrate affects the interface/membrane roughness si gnificantly for healing lengths S<xi where xi is the substrate roughne ss correlation length. However, for healing lengths S much greater tha n xi the rms roughness scales as a power law proportional to S-c with the exponent c characteristic of the system. Moreover, thermally induc ed roughness can dominate that induced from the substrate for large he aling lengths S (much greater than xi) and/or system temperatures T> T -sc.