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 Assistant: 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 doesnt 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 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

Improvement in hydrophobicity Changes in hydrophobicity from the control to the C-18 samples Glass increased o (201.9%) Tile increased o (33.76%) Aluminum increased o (49.94%) Wear Tests Changes in the hydrophobicity of the C-18 samples before and after soap washes Glass increased 4.80 o (6.60%) Tile decreased 4.72 o (6.73%) Aluminum decreased o (55.10%) Oven Trial Results

Found that aluminum had best overall results (though not the best improvement) Comparing C-18 samples Aluminum: o (hydrophobic) Glass: o Tile: o Oven Trial Results

Used C-18 on all three surfaces Heating Methods Results

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 coating Glass- 7.35° increase (11.57%) Tile ° 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

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