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?