Langmuir–Blodgett (LB) film is a nanostructured system formed when Langmuir films or Langmuir monolayers (LM) are transferred from the liquid-gas interface to solid supports during the vertical passage of the support through the monolayers. LB films can contain one or more monolayers of an organic material, deposited from the surface of a liquid onto a solid by immersing (or emersing) the solid substrate into (or from) the liquid. A monolayer is adsorbed homogeneously with each immersion or emersion step, thus films with very accurate thickness can be formed. This thickness is accurate because the thickness of each monolayer is known and can therefore be added to find the total thickness of a Langmuir–Blodgett film.

The monolayers are assembled vertically and are usually composed either of amphiphilic molecules with a hydrophilic head and a hydrophobic tail or nowadays commonly of nanoparticles.Langmuir–Blodgett films are named after Irving Langmuir and Katharine B. Blodgett, who invented this technique while working in Research and Development for General Electric Co.

APPLICATIONS

• LB films consisting of nanoparticles can be used for example to create functional coatings, sophisticated sensor surfaces and to coat silicon wafers.
• LB films can be used as passive layers in MIS (metal-insulator-semiconductor) which have more open structure than silicon oxide, and they allow gases to penetrate to the interface more effectively.
• LB films also can be used as biological membranes. Lipid molecules with the fatty acid moiety of long carbon chains attached to a polar group have received extended attention because of being naturally suited to the Langmuir method of film production. This type of biological membrane can be used to investigate: the modes of drug action, the permeability of biologically active molecules, and the chain reactions of biological systems.
• Also, it is possible to propose field effect devices for observing the immunological response and enzyme-substrate reactions by collecting biological molecules such as antibodies and enzymes in insulating LB films.
• Anti-reflective glass can be produced with successive layers of fluorinated organic film.
• The glucose biosensor can be made of poly(3-hexyl thiopene) as Langmuir–Blodgett film, which entraps glucose-oxide and transfers it to a coated indium-tin-oxide glass plate.
• UV resists can be made of poly(N-alkylmethacrylamides) Langmuir–Blodgett film.
• UV light and conductivity of a Langmuir–Blodgett film.
• Langmuir–Blodgett films are inherently 2D-structures and can be built up layer by layer, by dipping hydrophobic or hydrophilic substrates into a liquid sub-phase.
• Langmuir–Blodgett patterning is a new paradigm for large-area patterning with mesostructured features.Recently, it has been demonstrated that Langmuir–Blodgett is an effective technique even to produce ultra-thin films of emerging two-dimensional layered materials on a large scale