The deposition and characterization of multilayers of the ionophore valinomycin

Abstract

The deposition and characterization of Langmuir-Blodgett films of the ionophore valinomycin on single-crystal silicon and quartz substrates are described. To enable good monolayer transfer the substrates first need to be coated with a few fatty acid layers. The valinomycin is found to deposit onto either the hydrophobic or the hydrophilic surfaces of the fatty acid film. The valinomycin multilayers have been investigated using IR and UV spectroscopy. These techniques show that up to 60 layers of the ionophore may be built up with good reproducibility. A detailed investigation by ellipsometry has revealed a thickness gradient in the multilayers in the direction of dipping; the average thickness per monolayer is between 0.40 and 0.66 nm.