Shooting Nanoparticles Metallic Shine Size Matters

Understanding the structure of liquid/solid interfaces is important for applications such as catalysis and electrochemistry. Now, Voïtchovsky et al. report the probing of various liquid/solid interfaces, on an atomic and molecular scale, using small-amplitude modulation atomic force microscopy (AFM). The solid and the dynamically operated AFM cantilever are both immersed in the liquid during the imaging process. The method can be used to image a range of hard or soft materials, including mica, calcium carbonate (pictured), silicon carbide or a lipid bilayer, with water or dimethylsulphoxide as the solvent. The method produces high-resolution topographical images that resemble the known crystallographic forms of the analysed materials. In addition, Voïtchovsky et al. propose a model that explains the forces involved in image formation and then, by establishing a calibration curve using contactangle-derived data, can precisely map the interfacial energy with nanoscopic resolution. The researchers predict that the technique could be widely adopted because it requires no modification of a standard AFM instrument.