Surface chemistrySurface chemistry is chemical phenomena that occur at the interface of two phases, usually between a gas and a solid or between a liquid and a solid. One important aspect of surface chemistry studies is to determine whether a molecule attaches itself to a surface by chemisorption or by physisorption. Surface chemistry is of particular importance to the field of heterogeneous catalysis. The advent of scanning probe microscopies like atomic force microscopy (AFM) and scanning-tunneling microscopy (STM) has stimulated a considerable increase in research activity in surface chemistry. This increase is part of a more general interest in nanotechnology. Irving Langmuir was one of the founders of this field.