Fabrication of highly ordered multilayer thin films and its applications

Abstract

A new method is introduced to build up organic/organic multilayer films composed of cationic poly(allylamine hydrochloride) (PAH) and negatively charged poly(sodium 4-styrenesulfonate) (PSS) by using the spinning process. The adsorption process is governed by both the viscous force induced by fast solvent elimination and the electrostatic interaction between oppositely charged species. On the other hand, the centrifugal and air shear forces applied by the spinning process significantly enhance the desorption of weakly bound polyelectrolyte chains and also induce the planarization of the adsorbed polyelectrolyte layer. The film thickness per bilayer adsorbed by the conventional dipping process and the spinning process was found to be about 4 å and 24 å, respectively. The surface of the multilayer films prepared with the spinning process is quite homogeneous and smooth. Electroluminescence (EL) devices composed of alternating poly(p-phenylene vinylene) (PPV) and polyanions films show higher quantum efficiency when prepared by the spin self-assembly (SA) method.