Preparation of surfactant multilayer films on solid substrates by deposition from organic solution

The spreading of organic surfactant solutions on solid surfaces is shown to be a practical and efficient method to prepare homogeneous, substrate-aligned, thin organic films. The characterization of such solution-deposited films of phospholipids by X-ray diffraction, electron microscopy and ellipsometry is described. Under suitable conditions, solution spreading yields multilayer films which are aligned parallel to the substrate surface, adopt a well-defined layer thickness and thus display a single color, and exhibit a low density of morphological defects which are identified by electron microscopy. Conditions favorable to controlled multilayer deposition include the complete wetting of the substrate by the organic solution of surfactant and the minimization of mass flow during spreading and solvent evaporation. The choice of an appropriate spreading solvent was found to be crucial to producing homogeneous films.