langmuir

Langmuir refers primarily to Irving Langmuir (1881–1957), an American chemist and Nobel laureate whose work on surface phenomena helped establish the field of surface chemistry. The name is also associated with several concepts and instruments in adsorption science and plasma physics that bear his name.

Langmuir isotherm: This is a model of adsorption describing the formation of a monolayer on a homogeneous surface with equivalent adsorption sites and no interactions between adsorbed molecules. At low coverage the amount adsorbed is proportional to pressure, and at high pressure it approaches a maximum value corresponding to a complete monolayer. The equilibrium form is often written as q = q_max Kp/(1+Kp), where q is the amount adsorbed, p is pressure, and K is a constant.

Langmuir-Blodgett films: A technique developed by Langmuir and Katharine Blodgett for transferring a single molecular layer from the air–water interface to a solid substrate, enabling controlled deposition of multilayer films with defined thickness and molecular orientation. These films have applications in electronics, optics, and sensors.

Langmuir trough: An apparatus used to study Langmuir monolayers at the air–water interface. Movable barriers compress a Langmuir film, allowing measurement of surface pressure–area isotherms and analysis of molecular packing, phase behavior, and film properties.

Langmuir probe: A diagnostic instrument used in plasma physics to measure electron temperature, density, and plasma potential. By inserting a biased electrode into a plasma and recording current–voltage characteristics, researchers infer key plasma parameters.

Together, these concepts reflect Langmuir’s impact on surface science and experimental techniques across chemistry, physics, and engineering.