title: Modification of micronozzle surfaces using fluorinated polymeric nanofilms for enhanced dispensing of polar and nonpolar fluids.
abstract: In this work, we report on the surface modification of a micronozzle surface to enhance fluid dispensing in the nanoliter range. Unmodified dispensing chips usually suffer from lateral wetting of the nozzle surfaces by low surface tension liquids resulting in poor control of the volume of the dispensed fluid. Covalent attachment of a fluorinated acrylate polymer to the outer surface of the micronozzle using a novel UV irradiation process helps to overcome capillary and adhesive forces and results in an enhancement of the control on fluid dispensing in the nanoliter range. The modified nozzles have been tested with a variety of fluids having a wide range of surface tensions. The surface modification allows precise control of the dispensing of nanoliter droplets with a high degree of reproducibility.
authors.affiliation: Laboratory for MEMS Applications, Institute for Microsystems Technology, University of Freiburg, 79110 Freiburg, Germany.
authors.forename: J D Jeyaprakash S
authors.initials: JD
authors.lastname: Samuel
authors.forename: Reinhard
authors.initials: R
authors.lastname: Steger
authors.forename: Gerhard
authors.initials: G
authors.lastname: Birkle
authors.forename: Roland
authors.initials: R
authors.lastname: Zengerle
authors.forename: Peter
authors.initials: P
authors.lastname: Koltay
authors.forename: Jürgen
authors.initials: J
authors.lastname: Rühe
mesh_terms: D017611:Fluorine Compounds / Q000737:chemistry*; D007477:Ions / Q000737:chemistry; D046208:Microchip Analytical Procedures; D008855:Microscopy, Electron, Scanning; D015394:Molecular Structure; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D010777:Photochemistry; D011108:Polymers / Q000737:chemistry*; D012825:Silicon / Q000737:chemistry
chemical_list: D017611:Fluorine Compounds; D007477:Ions; D011108:Polymers; D012825:Silicon