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IMPROVING THE HYDROPHOBICITY OF KITCHENWARE THROUGH THE COVALENT BONDING OF PHOSPHONIC ACIDS. Emily Chen, Marcus Elias, Jonathan Lin, Nathaniel Okun Olabade Omole, Matthew Piccolella, Suraj Shukla Dominique Voso, Jonathan Wu, Peter Xiong, Tania Yu Advisor: Dr. Michael Avaltroni - PowerPoint PPT Presentation
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IMPROVING THE HYDROPHOBICITY OF KITCHENWARE THROUGH THE
COVALENT BONDING OF PHOSPHONIC ACIDS
Emily Chen, Marcus Elias, Jonathan Lin, Nathaniel Okun Olabade Omole, Matthew Piccolella, Suraj Shukla Dominique Voso,
Jonathan Wu, Peter Xiong, Tania Yu
Advisor: Dr. Michael AvaltroniAssistant: Liz Day
Polytetrafluoroethylene Highly hydrophobic Gold standard for non-stick cookware Durable, easy-to-clean Dangerous Remains in the body for 20 years Lab studies on rats reveal liver damage,
cancer, etc. Carcinogenic at high temperatures, flu-like
symptoms
What is Teflon®?
Siloxanes Used in Rain-X Long molecules with silicon group at head The industry standard to coat surfaces Unreliable, can be easily removed by water Physical attraction to a surface doesn’t work well
for oxide surfaces Material needs to be bonded covalently
Other Current Methods
Self-Assembled Monolayers – thin film (10 nm) that is physically (electrostatic) or chemically (covalent) bound to a surface
Bind to oxide surfaces µ-oxo groups: bridged oxygens on a surface,
unreactive Hydroxyl groups: -OH groups, more reactive
Can be achieved with phosphonic acids
What is a SAM?
Phosphonate group with n-carbon chain attached at the head
Covalently bonds at two locations on an oxide surface, creating a self-assembled monolayer
“Controlled Corrosion” tightly bound permanently attached completely covers surface
What is a Phosphonic Acid?
Water repellents for electronics Stents for the heart Orthopedic Implants Non-Stick Cookware
Possible Applications of SAMPs
Longer carbon chain lengths will cause more hydrophobic surfaces
Washing the samples will increase hydrophobicity
The oven heating method will be the most effective
Aluminum will improve the most
Our Hypotheses
Household materials tested Tile, glass, aluminum
Coatings Phosphonic acids with C-6, C-8, C-10, C-12,
C-14, C-16, and C-18 tails Different heating methods
Oven, heat gun, iron
Materials and Methods
Preparing Materials Cleaned each material using a warm bath of
ethanol Sanded the aluminum
Preparing Solutions 0.0001 mol of each acid dissolved in 100. mL
of 50% toluene and 50% ethanol by volume as solvent
Mixed polarity provides best bonding Applying
Spray bottle to apply, one spray to each surface
Rolled each surface with a Mayer Rod to ensure even coating
Materials and Methods
Bonding Phosphonic acid was bonded to the surface
either by oven (24 hours at 120°C), iron (5 minutes on highest setting), or heat gun (3 minutes on highest setting)
Wear Testing Distilled water for 5 minutes Rubbed with 50:50 soap-water solution
Materials and Methods
Used to measure the hydrophobicity of the surfaces
5 microliter droplet added to each surface Uses infrared light and a high definition
camera to take an image of a water droplet Used computer applications to measure the
base angles
Goniometer
Oven Trials C-6,8,10,12,14,16,18 were applied to the three
materials with the oven heating method Two wear tests
Water rinse Soap-water rub
Found that Increases in alkyl groups correspond to increases in hydrophobicity (verified our hypothesis)
Results
Tile Samples with Oven Heating
Tile Control Tile C6 Tile C8 Tile C10 Tile C12 Tile C14 Tile C16 Tile C180
10
20
30
40
50
60
70
80
Untreated Water
Soap
CON
TACT
AN
GLE
(D
EGRE
ES)
Improvement in hydrophobicity Changes in hydrophobicity from the control to
the C-18 samplesGlass increased 60.00o (201.9%)Tile increased 17.71o (33.76%)Aluminum increased 30.77o (49.94%)
Wear Tests Changes in the hydrophobicity of the C-18
samples before and after soap washesGlass increased 4.80o (6.60%)Tile decreased 4.72o (6.73%)Aluminum decreased 50.90o (55.10%)
Oven Trial Results
Found that aluminum had best overall results (though not the best improvement)
Comparing C-18 samplesAluminum: 92.37o (hydrophobic)Glass: 72.78o
Tile: 70.17o
Oven Trial Results
Used C-18 on all three surfacesHeating Methods Results
_x0004_Oven Heat Gun _x0005_ Iron0
10
20
30
40
50
60
70
80
90
100
Tile C18
Glass C18
Aluminum C18CON
TACT
AN
GLE
(D
EGRE
ES)
Heating Method Results The oven proved to be the best and most
consistent Even, constant spread of heat Relatively low temperatures
The iron is still a viable option Economically feasible Time constraints Only slightly lower results
The heat gun was consistently ineffective High temperatures decomposed the
phosphonic acids
Corollary Trials and Results The group then decided to use the
iron with phosphonic acids C-14,16, & 18
Hypothesized that the second coating would fill in the “gaps” in coating and create even coverage
The effects of a second coatingGlass- 7.35° increase (11.57%)Tile- 11.44° increase (15.79%)Aluminum- 2.22° increase (2.90%)
The group then decided to examine how the wear tests would affect the double-coated samples
Corollary Trial Results
Wear Tests on Double-Coated, C-18 Samples
_x0004_Tile _x0006_ Glass Aluminum-5
15
35
55
75
95
115
Control Untreated
Soap
CON
TACT
AN
GLE
(D
EGRE
ES)
Multiple coatings Different solvents Various heating methods Different carbon-chain lengths Other testing surfaces Increasing accuracy and precision
Opportunities for Future Research
Possible Systematic Errors Uneven heating coverage from the heat gun Cross-contamination (Mayer Rod, heating iron etc.) Human error
Slightly different procedures Not the exact same amount of solution was applied to each
sample Concentration of phosphonic acid solutions
Possible Random Errors Slight equipment malfunctions The scale used only measured weight to the third
significant figure
Sources of Error
C-18 was the most effective at increasing hydrophobicity
Glass was the most receptive surface for covalent bonding
Constant, relatively low heat, was the most effective heating method
In Conclusion
Dr. Avaltroni Dr. Miyamoto Liz Day The NJGSS Staff
Janet Quinn Anna Mae Dinnio-Bloch
John and Laura Overdeck The Crimmins Family Charitable Foundation NJGSS Alumni and Parents 1984 – 2012
Acknowledgements