The development of two-dimensional and three-dimensional structures composed of colloidal particles has been the focus of considerable research and development in recent years with respect to their various potential uses. For example, it is possible that articles comprising a pattern of colloidal particles may be useful in biochip devices and sensors, optoelectronic devices, and photonic bandgap materials. Micro- or nanoscale physical patterns can be prepared using photolithography, electron-beam lithography, ion-beam etching, flexography, and functional printing. The desire with any of these technologies is to provide accurately patterned colloidal particles or clusters of particles on a nanoscale. Attempts to accomplish this have been directed to the use of various functionalized colloidal particles having different charges.
For example, selective assembly of colloidal particles on a nanostructured template coated with multilayers of electrolytes is described by Kim et al. Adv. Mater. 2007, 19, 4426-4430.
Patterned articles with anionic and cationic regions are prepared using controlled electrostatic and capillary forces as described by Aizenberg et al., Phys. Rev. Lett. 2000, 84(13), 2997-3000.
WO 2008/045745 (McCarty et al.) describes self-assembled articles having a surface comprising immobilized particles having ionic functional groups of one type of charge and mobile counterion of another type of charge. It is said that such charged materials may be useful to direct electrostatic self-assembly of surfaces, microspheres, or other materials on a micro- or nanoscale.
Other technologies have been developed to provide microfabrication methods for making metallic, two-dimensional, and three-dimensional structures with conductive metals. Conductive patterns have been provided for these purposes using photolithography and imaging through mask materials as described for example of U.S. Pat. No. 7,399,579 (Deng et al.).
There is a need to find a simplified way to increase the selective deposition onto charged patterned materials particularly to form with high contrast ionic charge patterns.