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Improving the Hydrophobicity of Fabrics with the Use of Phosphonic Acids
Craig Barretto, Jonathan P. Chen, Ishaan Desai, Samuel Finegold, Aamod George, Madeleine Hu, Karen Nan, Rei Otake, Amrita Rao,
Carli Smolen, Lu Yin, David Zhao
Supervisor: Dr. Michael Avaltroni Assistant: Darius Rackus
Teflon®Teflon (PTFE) widely
known and used hydrophobic substance
Resistant to many extreme conditions, low µ value
Tends to flake off, potentially carcinogenic
F
F
F
Fn
Rain-X® Polydimethylsiloxane
(PDMS) Sprayed onDisadvantage: Not
permanent, weakens under external pressures
n Si(CH3)2Cl2 + n H2O → [Si(CH3)2O]n + 2n HCl
http://en.wikipedia.org/wiki/File:Water_beads_on_glass_surface.jpghttp://en.wikipedia.org/wiki/File:Silicone-3D-vdW.pnghttp://en.wikipedia.org/wiki/File:Pdms.png
Scotchgard™Treated fabrics become
water- and stain-resistantOriginal formula shown to the
rightWas shown to be
carcinogenicMain ingredient was changed
to PFBS
Phosphonic Acids
Self-Assembled Monolayers (SAM)
Structure & Function
Chain Lengths
HPA (C6)OPA (C8)DPA (C10)DDPA (C12)TDPA (C14)HDPA (C16)ODPA (C18)
HydrophobicityHydrophobic molecules usually non-polar
Water beads from cohesion and hydrogen bonds
Surface and water share least amount of area
θ
Hydrophobic
Hydrophilic
θ
Surface EnergyLower surface energy indicates greater hydrophobicity
Relationship between contact angle and surface energy described by Young's Equation
θc
Nylon-Spandex Blend (NSB)
•Nylon is a polyamide of amide linkages
•Spandex is an elastic, synthetic fiber
•85% nylon, 15% spandex
www.chemistryexplained.com/Ny-Pi/Nylon.html
Purpose and Hypothesis
Optimal phosphonic acid and procedure to coat fabric Increase hydrophobicity Speed up binding
process
Develop more hydrophobic swimwear
http://1.bp.blogspot.com/_ouC92wvILSw/SIFspwmW_BI/AAAAAAAACcY/mYej0D2fYMg/s400/Natural+water+drop+in+the+leaf.jpg
Preliminary Tests on NSBQualitative hydrophobicity testHeat resistance tests:
Conventional oven, iron, microwave, heat gunTests to see how NSB handled the
solution
NSB being ironedwww.asia.ru/images/target/photo/51646912/Steam_Iron.jpg
toluene
ethanolupload.wikimedia.org/wikipedia/commons/e/e8/Ethanol-structure.svgupload.wikimedia.org/wikipedia/commons/c/c3/Beaker.svg
Preliminary Tests on NSBQualitative hydrophobicity testHeat resistance tests:
Conventional oven, iron, microwave, heat gunTests to see how NSB handled the
solution
Chain Length Tests on Glass Slides
Solution dropped on and spread
3 heating methods for dehydration
Contact angles measured
NSB Hydrophobicity
Dipped in solution then air dried
3 heating methods for dehydration
Contact angles measured
Cotton Testing ProcedureDipped in ODPA and air dried
Heated using iron and microwave
Six coatings applied
Contact angles measured
Exposure Tests
Tests Washing Machine Chlorinated Water Deionized Water Control
C183 heating methods
www.toondoo.com/cartoon/557143
Glass Results
NSB Results
Comparison of Effectiveness of Drying Methods
Con
tact
Ang
le (
Deg
rees
)
Exposure Tests on NSB- Results
Contrasted with expectation Hydrophobicity higher after tests Control showed most decrease in
hydrophobicityTheories
Residue from detergent Reaction with surface Surface cleaning
Future Work
More samples to confirm findingsMore chain lengths used for exposure
tests, eg. C-12 and C-14 (worked best on glass)
Multiple coatings to one surface to determine its effects
Different surfaces
Conclusion
Based on the results obtained from this project, it can be concluded that the physical properties of a surface can be permanently altered to increase the hydrophobicity of the surface.
AcknowledgementsThanks to:
Dr. Michael AvaltroniDarius RackusDr. David MiyamotoRamé-Hart Instrument CompanyJohn and Laura OverdeckSponsors of NJGSS 2010 Program
Bayer HealthCareBristol-Myers SquibbNovartis
Questions?