Definition: A film of organic material (often surfactant molecules) assembled at the liquid-gas interface and subsequently transferred onto a solid substrate.
Surfactant molecules can form ultrathin and organized layers on the surface of a liquid. These films can form regular stacks (a multilayer) or become so thin that there it is only one molecule thick (a monolayer). Irving Langmuir and Katherine Blodgett founded the science of LB films early in the 20th century.
