title: Oleophobicity of Biomimetic Micropatterned Surface and Its Effect on the Adhesion of Frozen Oil.
abstract: The relationship between the oleophobicity of micropatterned surfaces and the reduction of oil adhesion at low temperatures was explored by using siloxane elastomer surfaces as a model system. Polydimethylsiloxane (PDMS) surfaces were fabricated with varying oleophobicity from oleophilic to superoleophobic by combing the blending of trichloro(1H,1H,2H,2H-perfluorooctyl)silane (FDTS) into PDMS with the construction of bioinspired micropillars. The oil contact angles of micropillars were >130°, with the largest contact angle measured to be 146°. The micropillared surface showed remarkable self-cleaning properties; the contact angle hysteresis was <15°. The transparent oil droplets on PDMS surfaces of varied oleophobicity were frozen into a white-colored solid at -25 °C with the aid of a cooling system. Adhesion forces of the frozen oil droplets were obtained from the knock-off tests, showing that the adhesion forces dropped with the increased oleophobicity. The largest adhesion force was observed on the oleophilic flat surface, while the lowest adhesion force was on the highest oleophobic micropillared surface. The relative effectiveness of chemical and physical modifications on adhesion strength reduction was studied in terms of FDTS and micropillars, respectively. The results showed that a reduction of adhesion strength by 4% was reached by blending FDTS into flat PDMS, while a much more pronounced reduction of frozen oil adhesion strength by 60% was achieved by blending FDTS into PDMS micropillars; these results suggested a possible synergic effect of the FDTS chemistry and micropillar on the reduction of adhesion strength of frozen oil droplets.
authors: Department of Chemical Engineering, University of Waterloo , 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada.|Waterloo Institute for Nanotechnology, University of Waterloo , 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada.
authors: Zihe
authors: Z
authors: Pan
authors: Department of Chemical Engineering, University of Waterloo , 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada.|Waterloo Institute for Nanotechnology, University of Waterloo , 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada.
authors: Wei
authors: W
authors: Zhang
authors: Magna Powertrain , 800 Tesma Way, Concord, Ontario L4K 5C2, Canada.
authors: Andrew
authors: A
authors: Kowalski
authors: Department of Chemical Engineering, University of Waterloo , 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada.|Waterloo Institute for Nanotechnology, University of Waterloo , 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada.
authors: Boxin
authors: B
authors: Zhao
mesh_terms: D000268:Adhesiveness; D032701:Biomimetics; D005615:Freezing; D008855:Microscopy, Electron, Scanning; D009821:Oils / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D009821:Oils