Connecting the Dots: Nanoparticles, Nanostructured Surfaces, and Wetting

The research in this thesis describes a physical way to produce nanosized particles (NPs). The inert gas condensation method with magnetron sputtering produces NPs from various single and multi-element compositions. The proper manufacturing of a monodispersed NPs beam with real size control in the nanometer range (10-9 m) combined with motif and composition control opens up many new, previously impossible opportunities (e.g., new catalyst, QDots, etc.). The different surfaces coated with these distinct NPs show wetting behavior different than the bulk solids of the same material. These nanoscale rough surfaces serve as model systems for some intriguing wetting behavior found in nature. Surfaces covered with various degrees of NPs show behavior that contradict the well-known models of wetting founded in 1805 by T. Young and later adapted for real surfaces by Wenzel and Cassie Baxter. The Hydrophobic yet high adhesion wetting behavior (known as the rose petal effect) of intrinsic hydrophilic material is explained by the pinning of the water triple line by the many small apexes from these NPs. In the wetting of surfaces, surface chemistry plays a crucial role. Clean surfaces are necessary to understand the intrinsic behavior of a (clean) surface and the subsequent role of (airborne hydrocarbon) surface contamination. This surface contamination can be removed by a UV-Ozone treatment. Moreover, the aging of Ag NPs was investigated. The aging of NPs leads to an increase in the size of the NPs, affecting it’s wetting properties. This aging is also associated with the presence of (initially invisible) Ag adatoms, remnants from the sputtering process. These adatoms were made visible due to the UV-Ozone treatment, and the imaging was (only) possible with the current state-of-the-art STEM.