IMPROVING THE HYDROPHOBICITY OF KITCHENWARE THROUGH THE COVALENT BONDING OF PHOSPHONIC ACIDS

1. 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

2. What is Teflon®? • 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

3. Other Current Methods • 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

4. What is a SAM? • 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

5. What is a Phosphonic Acid? • 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

6. Possible Applications of SAMPs Water repellents for electronics Stents for the heart Orthopedic Implants Non-Stick Cookware

7. Our Hypotheses 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

8. Materials and Methods • 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

9. 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

10. 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

11. Goniometer 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

12. Results • 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)

13. Tile Samples with Oven Heating

14. Oven Trial Results • Improvement in hydrophobicity • Changes in hydrophobicity from the control to the C-18 samples • Glass 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 washes • Glass increased 4.80o (6.60%) • Tile decreased 4.72o (6.73%) • Aluminum decreased 50.90o (55.10%)

15. Oven Trial Results • Found that aluminum had best overall results (though not the best improvement) • Comparing C-18 samples • Aluminum: 92.37o (hydrophobic) • Glass: 72.78o • Tile: 70.17o

16. Heating Methods Results Used C-18 on all three surfaces

17. 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

18. 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

19. Corollary Trial Results • The effects of a second coating • Glass- 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

20. Wear Tests on Double-Coated, C-18 Samples

21. Opportunities for Future Research Multiple coatings Different solvents Various heating methods Different carbon-chain lengths Other testing surfaces Increasing accuracy and precision

22. Sources of Error • 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

23. In Conclusion 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

24. Acknowledgements • 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