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Biomimetic Nano-Surface Creation

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Flow resistance decreases because of air-water interface ... Lotus leaves exhibit super-hydrophobicity due to their nano-scale surface ... – PowerPoint PPT presentation

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Title: Biomimetic Nano-Surface Creation


1
Biomimetic Nano-Surface Creation for Drag
Reduction in Fluid Power Systems
Stephen M. Moran August 9th, 2007
2
THE CONCEPT
  • Lotus leaves exhibit super-hydrophobicity due to
    their nano-scale surface geometry combined with
    an exterior chemistry with low surface energy
  • Flow resistance decreases because of air-water
    interface
  • Apply concept to fluid transmission lines in
    fluid power systems

Water droplets bead
CCEFP UROPCS S. Moran
3
PREVIOUS STUDIES
50 nm
300 nm
2 µm
100 nm
2 µm
(P. Joseph et al, 2006)
(T. Lin et al, 2005)
  • (J. Kim et al, 2002)
  • Surface
  • Nano-turf using silicon etching
  • Experiment
  • Water droplets and channel flow
  • (A. Balasubramanian et al, 2003)
  • Chemically treated foil

(C. Henoch, 2006)
  • Nano-particle spray coatings
  • Nano-grass using silicon etching
  • Carbon nano-tube forest
  • Water pipe flow
  • Free surface water flow
  • Water channel flow
  • Water droplets

theory ? smooth surface 30 µm microposts
of spacing ? 15 µm 30 µm ? 60 µm
? 150 µm
  • 10-50 pressure drop reduction with water
    achieved
  • No oil flows and very few pipe flows
  • No high pressure systems or flexible surfaces

CCEFP UROPCS S. Moran
4
THE APPROACH
  • First, research nano-coating effectiveness in
    increasing contact angle and decreasing sliding
    angle of liquid droplets

50 nm
  • Concurrently, determine optimal surface geometry
    using photolithography to fully control surface
    shape and scale
  • Currently impractical construction method for
    fluid lines
  • Modified nano-molding method may be possible
  • Finally, apply working surfaces to flow setup and
    investigate effectiveness in reducing friction
    loss in fluid transmission lines by comparing
    pressure drop measurements of lines with and
    without nano-texturing

CCEFP UROPCS S. Moran
5
EXPERIMENTAL SETUP
  • Setup for droplet experiments
  • Goniometer contact angle
    measurement
  • Droplet sliding angle measurement

CCEFP UROPCS S. Moran
6
EXPERIMENTAL SETUP
  • Initial Experiments with Droplets
  • Control LEXAN plate cleaned of particles
  • Textured 6 weight of TiO2 nanoparticles
  • 8 weight of Zonyl 8740
  • 86 weight of distilled water
  • spray coated from 30 cm distance
  • 2 coats
  • Liquid 1 distilled water
  • Liquid 2 Mobil DTE 11M hydraulic oil
  • Liquid 3 Mobil DTE 18M hydraulic oil
  • (viscosity approx 10x greater than 11M)
  • Measure contact angle vs. droplet size

CCEFP UROPCS S. Moran
7
RESULTS
  • CONTACT ANGLE RESULTS
  • 8.0 µL water droplet and 3.4 µL oil droplet (Bond
    numbers of water and oil droplet made equivalent)
  • Oil-water contact angles not equal ? liquid-solid
    surface tension effects must be taken into account

CCEFP UROPCS S. Moran
8
RESULTS
  • CONTROL SURFACE

CCEFP UROPCS S. Moran
9
RESULTS
  • CONTROL SURFACE

CCEFP UROPCS S. Moran
10
RESULTS
  • TEXTURED SURFACE

CCEFP UROPCS S. Moran
11
RESULTS
  • TEXTURED SURFACE

CCEFP UROPCS S. Moran
12
RESULTS
  • SLIDING ANGLE RESULTS

CCEFP UROPCS S. Moran
13
RESULTS
  • SLIDING ANGLE RESULTS

CCEFP UROPCS S. Moran
14
ONGOING WORK
  • Setup for flow experiments

Peristaltic Pump
Pulse Dampener
Test Section
Hydraulic Oil
?p
Differential Pressure Transmitter
CCEFP UROPCS S. Moran
15
ONGOING WORK
  • Flow Setup Scaling
  • Verify that flow parameters scale properly for
    smooth pipe
  • Viscosity
  • Length
  • Cross-sectional area
  • Flow rate
  • More Surface Work
  • Apply effective nano-surfaces to flow setup and
    investigate pressure drop reduction
  • Investigate and apply various fluorinated polymer
    films and Self-Assembling Monolayer (SAM)
    coatings to lower surface energy
  • Repel oil droplet staining because at first,
    sliding oil droplets left a trailing stain on
    nano-textured surfaces

CCEFP UROPCS S. Moran
16
THANK YOU
  • Thank you NASA ISGC, The Boeing Company, NSF,
    CCEFP for their financial support.
  • Special thanks to Dr. Eric Loth and graduate
    student Adam Steele.

CCEFP UROPCS S. Moran
17
QUESTIONS
CCEFP UROPCS S. Moran
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