3D X-ray micro computed tomography on multiphase drop interfaces: from biomimetic to functional applications

The investigation of multiphase interfaces and contact lines is a challenging research topic for comprehension of countless physical problems, both natural and imitated from nature, at the microscale (nearly 1 ??m). In presence of a three-phase interaction (liquid???gas???solid, or two immiscible liquids and a solid), different forces influence the evolution of the systemand lead it towards its mechanical equilibrium. Even for the seemingly very simple case of drops on solid surfaces, there are many attempts to investigate the involved effects, with the main aim to profitably replicate them for functional applications (biomimetics). Here we show that it is possible to visualize the real multiphase interface by X-ray micro-computed tomography (microCT), which is essentially a full volume 3D microscope, non-intrusive, with micrometric spatial resolution and suitable to operate even with matter opaque at visible wavelength. Consequently, microCT can also be applied to investigate complex wetting scenarios, to validate the theoretical models already available for such cases.