Surface energy of growth and seeding side of free standing nanocrystalline diamond foils

Nanocrystalline diamond foil (NCDF) is a self supporting, detached diamond layer with a thickness in the range of several 10μ. Its freestanding character allows the investigation of the surface energy considering the growth as well as the nucleation (seeding) side. This is shown here for the first time. Contact angles of different liquids on the NCDF were measured and the surface energies were calculated using the Owens–Wendt–Rabel–Kaelble (OWRK) method. A compulsive cleaning process with liquid substances like acetone has no effect on the surface energy. Nevertheless it is recommended to clean the surface before contact angle measurements to prohibit distractions by dirt. The polar surface energy component of a NCDF after cleaning is 3mN/m and the nonpolar component is 44mN/m. The NCDF's surface morphology which is induced by the choice of a template's structure does not influence the surface energy. A surface oxidation by hot air or oxygen plasma is resulting in a higher surface energy and more polar components on the nucleation side of the NCDF. This effect can be used to activate the surface for applications like gluing. •Successful contact angle measurement of an untreated as well as oxygen treated nanocrystalline diamond foil•Untreated nanocrystalline diamond foil compares well to standard nanocrystalline diamond films.•Oxygen treatment significantly increases surface energy of a nanocrystalline diamond foil.