Transcript Candle soot as a template for a transparent robust

CANDLE SOOT AS A TEMPLATE FOR A
TRANSPARENT ROBUST
SUPERAMPHIPHOBIC COATING
BY: GROUP 18
GRAPHICAL ABSTRACT
• Scientist have created a superamphiphobic
coating using candle soot and a silica layer
• This gives the surface both hydrophobic and oleophobic
properties
• Thermal stability: coating was able to maintain properties
until 400°C
• Abrasion stability: coating maintained properties until layer
was less than 2μm thick
www.huntsman.com
INTRODUCTION
• Superamphiphobic- meaning a surface is both
superhydrophobic and superoleophobic
• Hydrophobic- material is resistant to water
• Oleophobic- material is resistant to oil
• Example of a superamphiphobic coating:
http://www.youtube.com/wa
tch?v=IPM8OR6W6WE
INTRODUCTION
• In industry, it is desirable to have
hydrophobic/oleophobic surfaces. Because liquid
has a low affinity for the surface, the liquid beads
up, taking dirt and other particles with it.
• This makes the material self-cleaning
http://www.nanovere.com/nanotechnology.html
INTRODUCTION
Examples of Hydrophobic
materials
• Polyethylene
• Polypropylene
• Nylon 10,10
Examples of Oleophobic
materials
• Low surface energy
materials
BASIC PRINCIPLES
• When a liquid meets a
surface, it meets at an
angle where the
liquid/vapor interface
meets the solid
• This is called the contact
angle
• Hydrophilic surfaces
cause the water droplet
to spread out, resulting in
a smaller contact angle
(0-90°)
• Hydrophobic surfaces
have contact angles >90°
Makin' contact. (2011, 03 04). Retrieved from
http://materialsgirlny.tumblr.com/post/3638362998/makin-contact
www.ramehart.com
BASIC PRINCIPLES
• Roll-off angle: angle of
a surface where a drop
of liquid will start to
move
• Point where the force of
gravity overcomes the
force of surface tension
Bharat Bhushan, Yong Chae Jung, Natural and biomimetic artificial surfaces for
superhydrophobicity, self-cleaning, low adhesion, and drag reduction, Progress
in Materials Science, Volume 56, Issue 1, January 2011, Pages 1-108, ISSN 00796425, 10.1016/j.pmatsci.2010.04.003.
(http://www.sciencedirect.com/science/article/pii/S0079642510000289)
WORK PERFORMED
• Glass slide was held above a Paraffin candle and
coated in its soot
• Coating causes material to be superhydrophobic
• However, the soot structure is fragile
WORK PERFORMED
• Soot was coated with a layer of silica
• Using chemical vapor deposition of tetraethoxysilane and
catalized by ammonia
• This process makes the coating stronger
WORK PERFORMED
• The coated glass was
then calcinated at
600˚C to make it
transparent
• Coated with semifluorinated silane by
CVD
WORK PERFORMED
• Results show high contact angle with both water and
organic liquids relative to the original surface
WORK PERFORMED
• The coating began to break down:
• Thermal stability test• Fluorosilane began to break down at 400˚C- meaning coating
lost its oleophobic properities
• Silica network broke down at 1000˚C
• Abrasion stability test• Sand formed cavities in the coating, however, it maintained its
superamphiphobic properties until the coating was less than
2µm thick
Schematic of sand abrasion test
CONCLUSION
• This superamphiphobic coating is simple to make
and effective against water, oil, and other hexanes
• It is self cleaning because dirt and other solid particulate roll
off with the liquid
• It maintains its properties until 400°C
• It is transparent- opening up a wide range of applications
Jiang, W., Hu, H., & Zhang , Y. (2013). Publications. Retrieved from
http://www.chem.queensu.ca/people/faculty/Liu/publications.
html
ASSESSMENT OF THE WORK
• Possible improvements:
• The explanation of soot as the reason for the coating’s
superamphiphobic properties is never thoroughly explained
• The experiment lacks control over other possible
influencing variables
• The paper never explicitly explains what gives a material
oleophobic properties
www.aculon.com
ASSESSMENT OF THE WORK
• Analysis
• The paper presents a practical approach to making a
superamphiphobic coating
• From their test, the coating has a large number of useful
applications ranging from goggles to large scale chemical
production
• Further research is required before the small scale process
can be converted to a large scale commercialized product
• The small scale lab set up isn’t necessarily practical on an
industrial scale
• Cost analysis would be necessary to ensure profitability
FURTHER RESEARCH
• Methods of cost efficient mass production
• As we know, in industry, one of the most important
considerations is cost.
• If a company does not have a method to mass produce
material at a low cost then they will not make a profit.
• Research in this area would include searching for
commercially available materials that also have the correct
characteristics to create superamphiphobic properties
FURTHER RESEARCH
• How to make Fluorosilane remain
stabile at higher temps
•
As we have shown in our Work Performed,
Fluorosilane began to break down at 400˚Cmeaning coating lost its superamphibhobic
properties
•
For our superamphiphobic material to more
use,we need to increase to temperature
range in which Fluorosilane remains stable.
•
Many reactions take place at temperatures
higher than 400˚C. For these reactions, it is
desirable for an superamphiphobic material
to remain intact as a coating and not break
down and become a possible impurity.
http://www.chemspider
.com/ChemicalStructure.10328917.html
FURTHER RESEARCH
• Sand Abrasion
• The Sand Abrasion Test showed that the superamphiphobic
material is inevitably susceptible to wearing away.
• Research should be performed to find ways to make
superamphiphobic materials more resistant to wearing.
• This is important because a more robust material leads to a
longer lasting coating.
http://www.trl.com/services/materialstesting/abrasion.html
FURTHER RESEARCH
• Roll off angle
• There has been a lot of confirmed research in the area of
Contact angle.
• But, little to no information is given on Roll off Angle.
• Research in this area would consist of experimentally finding
correlations between Roll off Angle and specific qualities of
materials.
• End goal of statistical model for roll off angle.
REFERENCES
• Contact angle. (n.d.). Retrieved from
http://membranes.edu.au/wiki/index.php/Contact_Angle
• Deng, X., Mammen, L., Butt, H. & Vollmer, D. (2011, 12 01). Candle
soot as a template for a transparent robust superamphiphobic
coating. Science, 335, 6064. Retrieved from
http://www.sciencemag.org/content/335/6064/67.abstract?sid=b8c
ea070-e429-4c98-897c-8c6b8adb8dc3
• Diversified Enterprises. (2009). Critical surface tension and contact
angle with water for various polymers. Retrieved from
http://www.accudynetest.com/polytable_03.html?
• All uncited figures are taken from cited paper