title: Completely superhydrophobic PDMS surfaces for microfluidics.
abstract: This study presents a straightforward two-step fabrication process of durable, completely superhydrophobic microchannels in PDMS. First, a composite material of PDMS/PTFE particles is prepared and used to replicate a master microstructure. Superhydrophobic surfaces are formed by subsequent plasma treatment, in which the PDMS is isotropically etched and PTFE particles are excavated. We compare the advancing and receding contact angles of intrinsic PDMS samples and composite PTFE/PDMS samples (1 wt %, 8 wt %, and 15 wt % PTFE particle concentration) and demonstrate that both the horizontal and vertical surfaces are indeed superhydrophobic. The best superhydrophobicity is observed for samples with a PTFE particle concentration of 15 wt %, which have advancing and receding contact angles of 159° ± 4° and 158° ± 3°, respectively.
authors.affiliation: Laboratory for MEMS Applications, IMTEK-Department of Microsystems Engineering, University of Freiburg, Georges-Koehler-Allee 103, Freiburg im Breisgau, Germany 79110. artur.tropmann@imtek.uni-freiburg.de
authors.forename: Artur
authors.initials: A
authors.lastname: Tropmann
authors.forename: Laurent
authors.initials: L
authors.lastname: Tanguy
authors.forename: Peter
authors.initials: P
authors.lastname: Koltay
authors.forename: Roland
authors.initials: R
authors.lastname: Zengerle
authors.forename: Lutz
authors.initials: L
authors.lastname: Riegger
mesh_terms: D004129:Dimethylpolysiloxanes / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D044085:Microfluidics / Q000379:methods*; D008855:Microscopy, Electron, Scanning; D058626:Plasma Gases; D011138:Polytetrafluoroethylene / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D004129:Dimethylpolysiloxanes; D058626:Plasma Gases; D011138:Polytetrafluoroethylene