interfaciales

Interfaciales refers to phenomena and properties at the boundaries between distinct phases, including solid–liquid, liquid–liquid, and gas–liquid interfaces. It is a multidisciplinary subject in chemistry, materials science, and physics, and it influences wetting, adhesion, mass transport, catalysis, corrosion, and the stability of emulsions and foams. The interfacial region often differs in structure and composition from the bulk, giving rise to effects such as interfacial tension and electrical double layers.

Key concepts include interfacial tension, the work required to create new surface; wetting and contact angle, describing how a liquid spreads on a surface; adsorption and interfacial films; capillarity; and interfacial rheology, the study of viscoelastic properties of films at interfaces. In electrochemical systems, the electrical double layer governs charge distribution and rate processes at the interface.

Techniques for studying interfaciales include tensiometry to measure interfacial tension; microscopy (AFM, SEM, TEM) to resolve structure; spectroscopy at interfaces; ellipsometry for thin films; and methods that probe surface charge such as zeta potential. Theoretical models draw on thermodynamics and interfacial science, including the Gibbs dividing surface and Young’s equation for contact angles.

Applications include stabilization of emulsions and foams, coatings and paints, polymer blends and composites, catalysis on solid supports, membranes, and energy technologies such as batteries and fuel cells. Challenges include dynamic, non-equilibrium interfaces, nanoscale roughness, and contamination that disrupt ideal behavior. See also surface science, interfacial chemistry, and colloid science.