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
Rain-X®

Polydimethylsiloxane
(PDMS)
 Sprayed on
 Disadvantage: 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.jpg
http://en.wikipedia.org/wiki/File:Silicone-3D-vdW.png
http://en.wikipedia.org/wiki/File:Pdms.png
Scotchgard™




Treated fabrics become
water- and stain-resistant
Original formula shown to the
right
Was shown to be
carcinogenic
Main ingredient was changed
to PFBS
Phosphonic Acids

Self-Assembled
Monolayers (SAM)

Structure & Function

Chain Lengths
ODPA
HPA
DPA
DDPA
TDPA
HDPA
(C6)
(C14)
(C12)
(C16)
(C18)
OPA (C10)
(C8)
Hydrophobicity
Hydrophobic
molecules
usually non-polar
Water
beads from
cohesion and hydrogen
bonds
Surface
and water share
least amount of area
θ
Hydrophobic
θ
Hydrophilic
Surface Energy
Lower
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 NSB
Qualitative hydrophobicity test
 Heat resistance tests:



Conventional oven, iron, microwave, heat gun
Tests to see how NSB handled the
solution
NSB being ironed
www.asia.ru/images/target/photo/51646912/Steam_Iron.jpg
Preliminary Tests on NSB
Qualitative hydrophobicity test
 Heat resistance tests:



Conventional oven, iron, microwave, heat gun
Tests to see how NSB handled the
solution
toluene
upload.wikimedia.org/wikipedia/commons/e/e8/Ethanol-structure.svg
upload.wikimedia.org/wikipedia/commons/c/c3/Beaker.svg
ethanol
Chain Length Tests on Glass Slides
 Solution
3
dropped on and spread
heating methods for dehydration
 Contact
angles measured
NSB Hydrophobicity
 Dipped
3
in solution then air dried
heating methods for dehydration
 Contact
angles measured
Cotton Testing Procedure
 Dipped
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
C18
 3 heating methods

www.toondoo.com/cartoon/557143
Average Contact Angle (degrees)
Contact Angles on Coated Glass Samples
120
100
80
Glass Results
60
40
20
0
Control HPA
(C6)
OPA
(C8)
DPA
(C10)
DDPA TDPA HDPA ODPA
(C12) (C14) (C16) (C18)
Chain Length
Average Contact Angle (degrees)
Contact Angles on Coated NSB Samples
145
140
135
130
125
120
115
110
105
100
NSB Results
Microwave
Iron
Oven
Phosphonic Acid ( Carbon Chain Length)
Comparison of Heating Application Methods
128
126
124
Contact Angle (Degrees)
Average Contact Angle (Degrees)
130
122
120
Comparison of Effectiveness of
Drying Methods
118
116
114
112
110
Microwave
Iron
Heat Application Method
Oven
Exposure Tests on NSB- Results

Contrasted with expectation
 Hydrophobicity
higher after tests
 Control showed most decrease in
hydrophobicity

Theories
 Residue
from detergent
 Reaction with surface
 Surface cleaning
140
Contact Angles on Coated Cotton Samples
120
Contact Angle (°)
100
80
Microwave
60
Iron
40
20
0
Control
C18
Chain Length
Future Work
More samples to confirm findings
 More 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.
Acknowledgements
Thanks to:
Dr. Michael Avaltroni
Darius Rackus
Dr. David Miyamoto
Ramé-Hart Instrument Company
John and Laura Overdeck
Sponsors of NJGSS 2010 Program
Bayer HealthCare
Bristol-Myers Squibb
Novartis
Questions?