Langmuir–Blodgett films of long-chain amines

Abstract

Widespread interest has developed in the potentialities of molecular films built up on solids by the Langmuir–Blodgett (L–B) technique of sequential transfer of monomolecular layers from a water surface^1,2. For certain purposes, the fatty acid soaps which are the classical, and most extensively studied, constituents of L–B films, may be unusable. For example, it may be desired to incorporate acid-sensitive molecules, or the presence of heavy-metal ions such as barium or cadmium, which are required to produce the most stable soap layers, may be undesirable. These problems may be overcome in some instances by the use of fatty alcohols or esters, but multilayers of these substances are generally less stable (especially with respect to thermal disruption or vaporization) than those of the heavy-metal soaps. I now report methods for the facile formation of L–B layers of long-chain amine salts which offer comparable, as well as complementary, advantages compared with soap films.