This file encloses a brief understanding of the technique of harvesting water from collecting fog from hilly areas as inspired from Namib desert beetle. you can find methods, materials, process and its resulting conclusion and discussion
Selaginella: features, morphology ,anatomy and reproduction.
Beetle like droplet-jumping superamphiphobic coatings for enhancing fog collection
1. BEETLE-LIKE DROPLET-JUMPING SUPERAMPHIPHOBIC
COATINGS FOR ENHANCING FOG COLLECTION OF SHEET
ARRAYS
XIKUI WANG, JIA ZENG, XINQUAN YU, CAIHUA
LIANG AND YOUFA ZHANG
PRESENTED BY:
JYOTI (191503)
M.SC. BIOTECHNOLOGY 3RD SEM
2. Without food, human beings can live for 14
days or more.
Human body can only survive a few
days without water.
Having access to safe and sufficient water and sanitation are now recognized
as a basic human right.
DID YOU KNOW?
3. One billion people worldwide live without clean, safe drinking water, Two billion live
without basic sanitation
4. INTRODUCTION
An effective way to overcome water scarcity in arid and semi-arid areas is water
harvesting from fog collection.
Inspired by the bumpy surface of the desert beetle.
A beetle-like superamphiphobic coating (BSC), which with high nucleation rate and
rapid droplet removal performance.
Low cost and easy preparation is developed.
This study offer insight for the design of fog collectors, which is important for
developing materials that can be extended to application in water collection,
desalination, heat transfer and other fields.
5. METHODS AND MATERIALS
• Aluminium sheets (99.95%, ∼5 cm × ∼5 cm × ∼0.3 mm)
• 1H,1H,2H,2H-Perfluorodecyltriethoxysilane (FAS)
• Chained nano-SiO2 sol,
• Deionized water and anhydrous ethanol,
• Tetraethyl orthosilicate (TEOS)
• Ammonium hydroxide
• SiC particles (diameter: 7 μm–12 μm)
7. 80 mL of ethanol + 4
mL of ammonia
hydroxide + 1.2 mL of
chained nano-SiO2 sol
+ 0.6 mL of TEOS +
0.5 mL of FAS.
0.132 g of SiC particles
were added to a beaker
of 45 mL of the nano-
SiO2 superamphiphobic
paints.
Mixture is Pressure-
sprayed onto an
aluminum sheet or
glass substrate. After
then, a BSC was formed
after drying at 80 °C.
8. SURFACE
PERFORMANCE OF
COATINGS
A) SEM image of the Nano.
(b) Reveals that some SiC particles
are exposed outside the nano-
SiO2 superamphiphobic coating
(c) shows that although some SiC
particle are embedded into the
nano-SiO2 particles, and partial
regions are exposed
(d) Side view of the beetle-like
superamphiphobic coating.
9. WETTABILITY
Water/oil contact angles for the
Nano and the BSC are both more
than 150°, while the water/oil roll
angles are less than 5°
Contact angles of the SiC particles
are ∼107.6° and ∼29.3° there is very
little fluorine (F) on the SiC particles,
but a lot of fluorine on the silica
particles.
BSC is a hybrid wetting coating with
wettability difference between the
SiC particles and nano-
SiO2 particles.
https://pubs.rsc.org/image/article/2020/ra/c9ra09329j/
c9ra09329j-f3.gif
10. CONDENSATION
DYNAMICS
These figures shows that surface
coverage for the BSC is higher than
that of the Nano due to its higher
nucleation at the early stage.
After 25 min, surface coverage for
the BSC is close to that of the Nano
the reason is during the condensation
process, droplets coalescence and
self-repelled jumping are captured
which is beneficial to drops departure
and reduce the surface coverage.
Untreated surface increases gradually
as time goes on, and then, it
approaches 100% after 30 min, which
reveals that hydrophilic surface is not
conducive to the removal of water
droplets.
https://pubs.rsc.org/image/article/2020/ra/c9ra09329j/c9ra09329j-
f4.gif
11. FOG COLLECTION
PERFORMANCE
Formula for fog collection RC =W/TS
where Rc = the water collection rate (g
m−2 h−1)
W = weight of the collected water (g)
T = fog/water collecting time (h)
S = the area fog/water collecting
surface (m2)
Rd = Wc /Wc + Wr x 100%
Rd = drop removal efficiency
Wc = weight of the collected water (g)
Wr = weight of the retained water (g)
https://pubs.rsc.org/image/article/2020/ra/c9ra09329j/c9
ra09329j-f5.gif
12. DROP REMOVAL
EFFICIENCY
• (a) Schematic diagram of water
collecting device.
• (b) The weight of collected water as a
function of time, and the space
between the two collision surfaces are
various from ∼1 mm to ∼12 mm.
• (c) Time-lapse images for droplets
jump and collide with each other to
removal between two collision
surfaces (S ≈ 2 mm).
https://pubs.rsc.org/image/article/2020/ra/c9ra0932
9j/c9ra09329j-f6.gif
14. CONCLUSION
• A simple, low-cost and effective method for fabricating a beetle-like superamphiphobic
coating with efficient fog collection
1. high nucleation rate
2. efficient water droplet removal efficiency
3. commendable water collection efficiency
• A novel method to promote the drop removal by the collision of jumping droplets
between two array sheets, and when the spacing between the two parallel samples was
about 2 mm, the water collection rate of the collision surface was increased by ∼216%
compared to that of the non-collision surface.
• Wide application prospects in fog/water collection, desalination, heat transfer, anti-
fogging and other fields.
15. REFERENCES
• Beetle-like droplet-jumping superamphiphobic coatings for enhancing fog
collection of sheet arrays
Xikui Wang, Jia Zeng, Xinquan Yu, Caihua Liang and Youfa Zhang
Jiangsu Key Laboratory of Advanced Metallic Materials, School of Materials Science
and Engineering, Southeast University, Nanjing, PR China.
• https://pubs.rsc.org/en/content/articlelanding/2020/ra/c9ra09329j
