Selective deposition in layer-by-layer assembly: Functional graft copolymers as molecular templates

A new approach to creating patterned composite structures with layer-by-layer assembled thin films is introduced. In this approach, the top surfaces of layer-by-layer films are chemically patterned by the direct stamping of functional polymers on the surface. The resulting pattern is then used as a template for the further deposition of materials on the surface. This paper illustrates this concept through the patterning of an oligoethylene glycol resist atop a polyelectrolyte multilayer surface. The resist layer is created by stamping an oligoethylene oxide-maleic anhydride graft copolymer onto the top polyamine surface. Further deposition of polyions results in the formation of a patterned polymer film atop the original multilayer thin film. When a patterned polyelectrolyte film is used as the base layer or substrate in this process, a second pattern can be stamped atop the original patterned array. Subsequent selective adsorption of polymers yields a second level of microstructures, illustrating the concept of multiple level patterning for layer-by-layer thin films; this concept can be broadened to include selective deposition of numerous materials on top of multilayer polymer systems.