A brief introduction to superhydrophobicity. Superhydrophobicity is defined as well as explained in simple terms. Furthermore, demo videos are shown to showcase the differences between superhydrophobic surfaces and hydrophilic surfaces. Finally, potential applications for this technology are explored.
3. How does superhydrophobicity occur?
• Microroughness
o Commonly done with etched
microstructures into a silicon
wafer
• Hydrophobic Coating
o Chemically treating the surface
with polar chemicals
(hydrophobic)
o Examples: Teflon, oil, etc.
From news.byu.edu - An example of pillar microstructure on a silicon wafer
4. How does superhydrophobicity occur?
• With water’s surface tension, it is
unable to penetrate into the gaps
between the ribs/pillars.
• While the no-slip condition occurs
on the top of the substructure,
water slips over the gaps. Overall,
friction is reduced.
• This drag reduction gives the
appearance of the water slipping
across the surface. From news.byu.edu - An example of rib microstructure on a silicon wafer.
These gaps are about 30 microinches wide.
7. Droplet Sliding ~80° Incline
Hydrophilic
• Took about 33 s
• Speed: 4.67x
Superhydrophobic
• Took about 0.02 s
• Speed: 0.003x
8. So what...
• Vehicle Coating
o Typical dirt/mud
attaches to a
hydrophilic
surface.
o Repels water and
dirt from
attaching on car
surface
*Image taken from extremetech.com/extreme/181370-nissans-self-cleaning-car-could-kill-off-car-washing-forever
9. So what...
• Reduce impact of water on airplanes
• Prevents ice buildup
*Image from imagesource.com
10. So what...
• Requires less pressure to
pump a fluid through pipes
o Drag in pipes is a function of
friction drag. The less friction
involved, the less pressure
required
*Image from imagesource.com
11. So what...
• Biomedical Tools
o Prevents
internal fluids to
attach to
instruments
*Biomedical tool used for cell manipulation. Image taken from “Micro-Nano Technologies for Cell Manipulation and
Subcellular Monitoring” by M.J. Lopez-Martinez and E.M. Camp
