Electrophoretic deposition through colloidal suspension: A way to obtain nanostructured conjugated polymer film

Nanostructured films of various conjugated polymers can be obtained through electrophoretic deposition process. Unlike the conventional deposition techniques based on the solutions of conjugated polymer, the methods employing colloidal suspensions like one proposed here make it to possible to separate the solidification of material from the film formation and drying steps. This unique feature provides nanostructure in the films deposited. A simple method, pouring a dilute solution of target material into an excess of non-solvent liquid, was used to obtain suspensions of conjugated polymers. Since this method is similar to a step of purification of the polymers after polymerization and does not use any additives such as surfactant, the polymers in the suspension and therefore the films obtained through the electrophoretic deposition may keep at least the purity of the original material. The unique morphology found in the electrophoretically deposited films opens up the new application of polymer light-emitting devices other than displays, the artificial fingerprint devices for anti-forging technology applicable to smartcards. Additionally, a unique process to obtain polymer-fullerene nanocomposite for photovoltaic application through the electrophoretic deposition is also proposed.