Plasma induced patterning of polydimethylsiloxane surfaces

We report on a plasma-based method to fabricate chemical and physical patterns on polydimethylsiloxane (PDMS) surfaces. A copper TEM grid was placed on cured, planar (2D) and periodic (3D) PDMS surfaces, and the samples exposed to a low-pressure air plasma. The pattern of the grid was precisely replicated, forming hydrophilic channels only where the grid wires contacted the PDMS surface. Exposed regions of the surface between the mesh wires were not chemically modified and retained their hydrophobic character. This plasma-based procedure provides a simple, fast, and inexpensive method for creating patterned chemical functionalities on 2D and 3D PDMS surfaces for directed assembly and for the development of micro-scale sensors and bio-chip devices. (C) 2008 Elsevier B.V. All rights reserved.