Super-hydrophobic, highly adhesive, polydimethylsiloxane (PDMS) surfaces

Super-hydrophobic surfaces have been fabricated by casting polydimethylsiloxane (PDMS) on a textured substrate of known surface topography, and were characterized using contact angle, atomic force microscopy, surface free energy calculations, and adhesion measurements. The resulting PDMS has a micro-textured surface with a static contact angle of 153.5 degrees and a hysteresis of 27 degrees when using de-ionized water. Unlike many super-hydrophobic materials, the textured PDMS is highly adhesive, allowing water drops as large as 25.0 mu L to be inverted. This high adhesion, super-hydrophobic behavior is an illustration of the petal effect. This rapid, reproducible technique has promising applications in transport and analysis of microvolume samples. (C) 2011 Elsevier Inc. All rights reserved.