Influence of substrates on roughness of self-supporting Ni films

Self-supporting Ni foils were obtained by floating of Ni films from water soluble substrates. Ni films were prepared by metal vapor vacuum arc (MEVVA) ion deposition. The following release agents were applied on Si wafer substrates: betaine monohydrate with sucrose, potassium oleate, potassium oleate with sucrose. In addition polished NaCl crystals and self-supporting collodion foils were used as soluble substrates, respectively. Field emission scanning electron microscopy (FESEM) and atomic force microscope (AFM) were employed to analyze the surface morphology and the roughness of the Ni films and the substrates. The results indicate that the mean roughness of the self-supporting Ni foils depends on their substrates. Self-supporting collodion foils seem to be one of the most suitable candidates for preparing self-supporting Ni foils with low roughness. Mean roughness of the best self-supporting Ni foils is about 3.8 nm.