Study On The Fabrication Of Superhydrophobic Micro-and Nano-structures

Wettability is an important property of the solid surface. Surfaces with water contactangle (CA) of larger than150°and sliding angle (SA) of lower than10°are so-calledsuperhydrophobic ones. In the last two decades, superhydrophobicity has been attractedgreat interest of scientists with its huge potential applications. In nature, a typical exampleof superhydrophobicity is lotus leaf with a CA of as high as160°, due to both themicro-papillae and the low-surface-energy wax-like crystals. In this thesis, we studied fourdifferent hydrophobic surface structures fabricated by building suitable levels ofroughness on the surface of polydimethylsiloxane (PDMS).(1) PDMS was spun on the glass surface, then, nano candle soot particles were coatedon PDMS and followed by solidification in blast oven. Smooth PDMS surfaces coveredwith nano particles were obtained.(2) Nano candle soot particles were coated on a glass surface, and followed by a spunlayer of PDMS. A second layer of candle soot was coated on the rough PDMS surface andfollowed by solidification in blast oven. Superhydrophobic surfaces were obtained.(3) Spun a layer of PDMS film on glass. A large amount of candle soot was coated onPDMS and followed by solidification in blast oven. Porous PDMS surface with nano sootparticles was obtained.(4) In order to mimic the micro-nano-binary structures of the well-known lotus leaf,we presented a novel method to fabricate superhydrophobic surfaces by combiningmicro-size dot-matrix and nano-size candle soot particles. PDMS, as a binder, was used tofix soot particles.Water wettability of the above surface structures was studied systematically. CA of164°and SA of1-3°was achieved.