Control of the homogeneity of Langmuir-Blodgett films using the deposition-induced flow in the monolayer

Abstract

The flow in the floating monolayer that is associated with the deposition of Langmuir-Blodgett (LB) films in the conventional vertical dipping method leads to a gradual change in the properties of subsequently deposited layers. It is found that this change is especially marked during a short induction period, after which a steady state is achieved where changes become very small on a film balance of suitable size and geometry. To fabricate homogeneous LB films that consist of only these pre-flow modified, steady state layers, the monolayer is subjected to flow before the first layer is deposited. These homogeneous samples exhibit properties that are markedly different from those of conventional films where the properties of the first individual layers change. The method is especially suitable for large-scale, continuous production of L film coatings, but may be used on a laboratory scale after minor modification of the standard deposition procedure. Several applications for basic research are obvious.