surfacescience

Surface science is the study of physical and chemical phenomena at interfaces, with emphasis on solid–gas and solid–liquid interfaces and their relationship to bulk properties. It seeks to understand how atomic arrangement, electronic structure, and chemical composition at a surface govern processes such as adsorption, diffusion, catalysis, corrosion, and wetting. Surfaces often differ markedly from the bulk in structure and chemistry, exhibiting reconstructions, altered electronic states, and reduced coordination that influence reactivity and stability. A central concept is surface energy, which drives phenomena like grain growth and phase transitions, and the work function, which controls electron emission and contact with metals.

Common experimental tools include surface-sensitive spectroscopies (XPS, UPS, NEXAFS), diffraction (LEED), and microscopy (STM, AFM). Other methods measure wetting, thickness, or optical properties, such as contact-angle goniometry and ellipsometry. Theoretical approaches combine thermodynamics of interfaces with quantum-chemical calculations, including density functional theory, to model adsorption energies, surface reconstructions, and reaction pathways.

Applications span catalysis, electrochemistry at interfaces, semiconductor fabrication, corrosion protection, protective coatings, lubrication (tribology), and biomaterial interfaces. Subfields include physical chemistry of surfaces, catalysis science, materials science of coatings, and nanoscience of two-dimensional materials. The field has origins in surface thermodynamics and adsorption theory advanced in the early 20th century, with breakthroughs in imaging and spectroscopy in the late 20th century enabling direct visualization and characterization of surfaces at the atomic scale.