Polymer-on-polymer stamping: Universal approaches to chemically patterned surfaces

A new approach to create chemically patterned surfaces utilizing polymers and copolymers is introduced. In this approach, chemical patterns are achieved by the direct stamping of functional polymers onto a surface containing complementary functional groups. The resulting pattern is then used as a template for the further deposition of materials on the surface. This concept can be applied to various functional polymer and substrate systems as well as different thin film deposition techniques. This approach is demonstrated with the direct stamping of polystyrene-poly(acrylic acid) block copolymers (PS-PAA) to create alternating hydrophobic/hydrophilic regions and polyelectrolytes to create alternating positively and negatively charged regions. This approach has been used for patterning surfaces and templating materials deposition. When a patterned polyelectrolyte film is used as the base layer or substrate in this process, functionality can be incorporated in the underlying layer, making this approach particularly relevant to device and sensor applications. This approach is universal to a number of substrates, many of which can be used to adsorb a polyelectrolyte layer to provide a functional surface. Various substrates such as Si, glass, and plastic can be patterned with this method with relative ease, and without the need for traditional alkanethiol or silane monolayers. Factors such as stamping temperature, contact time, and substrate pretreatment on the nature of the transferred pattern have been investigated and will be discussed.