The potential theory of Polanyi, also called Polanyi adsorption potential theory, is a model of adsorption proposed by Michael Polanyi where adsorption can be measured through the equilibrium between the chemical potential of a gas near the surface and the chemical potential of the gas from a large distance away. In this model, he assumed that the attraction largely due to Van Der Waals forces of the gas to the surface is determined by the position of the gas particle from the surface, and that the gas behaves as an ideal gas until condensation where the gas exceeds its equilibrium vapor pressure. While the adsorption theory of Henry is more applicable in low pressure and BET adsorption isotherm equation is more useful at from 0.05 to 0.35 P/Po, the Polanyi potential theory has much more application at higher P/Po (~0.1–0.8). Overview Michael Polanyi Michael Polanyi, FRS (11 March 1891 – 22 February 1976) was a Hungarian polymath, who made theoretical contribution to physical chemistry, economics, and philosophy. Polanyi was a well known theoretical chemist who contributed to the chemistry field through three main areas of study: adsorption of gases on solids, x-ray structure analysis of the properties of solids, and the rate of chemical reactions. However, Polanyi was active in both theoretical and experimental studies within the Chemistry field. Polanyi obtained a degree in medicine in 1913 as well as a Ph.D. in physical chemistry in 1917 from the University of Budapest. Later in his life, he taught as a chemistry professor at the Kaiser Wilhelm Institute in Berlin as well as the University of Manchester in Manchester, England. History Proposed theory In 1914, Polanyi wrote his first paper proposed on adsorption where he proposed a model for the adsorption of gas onto a solid surface. Afterwards, he published a fully developed paper in 1916, which included experimental verification by his students and other authors. During his research in the University of Budapest, his mentor, Professor Georg Bredig, sent his research findings to Albert Einstein. Einstein wrote back to Bredig stating: The papers of your M. Polanyi please me a lot. I have checked over the essentials in them and found them fundamentally correct. Polanyi later described this event by saying: Bang! I was a scientist. Polanyi and Einstein continued to write to each other on and off for the next 20 years. Criticism Polanyi's model of adsorption was met