Monolayers of Macromolecules at the Water Surface

Many macromolecules (such as proteins) form stable monolayers at the water surface if the hydrophilic-lipohilic balance (HLB) is of the right quantity. Especially, almost all proteins (hemoglobin, ovalbumin, bovine serum albumin, lactoglobulin, etc.) are reported to form stable monolayers at the water surface. 

6 LANGMUIR-BLODGETT (LB) FILMS (TRANSFER OF LIPID MONOLAYERS ON SOLIDS) 

Some decades ago (Langmuir, 1920), it was reported that, when a clean glass plate was dipped into water covered by a monolayer of oleic acid, an area of the monolayer equal to the area of the plate dipped was deposited on withdrawing the plate. Later, it was found that any number of layers could be deposited successively by repeated drippings, later called the Langmuir-Blodgett (LB) method (Petty, 1996 Roberts, 1990 Birdi, 1989). 

In another context, the electrical properties of thin films obtained by different procedures, for example, thermal evaporation in vacuum, have been investigated in much detail. However, the films deposited by the LB technique have only recently been used in electrical applications. Thickness in LB films can be varied from only one monomolecular layer (ca. 25A = 25 10 10m), while this is not possible by evaporation procedures. 

Scientists are currently using LB film assemblies as solutions to problems in diverse areas such as microlithography, solid-state polymerization, light guiding, electron tunneling, and photovoltaic effects. In the case of such films as Mg stearate, if a clean glass slide is dipped through the film, a monolayer is adsorbed on the downstroke. Another layer is adsorbed on the upstroke. Under careful conditions, 

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