Recent Advances in Atmospheric Plasma
Treatment of Textiles
Gregory Roche, Carrie Cornelius, Wade Tyner
ApJet, Inc.
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Gregory Roche
Abstract
 Atmospheric pressure plasma is a revolutionary new technology for
surface finishing and pretreatments. Atmospheric pressure plasma
produces no waste water, requires no ovens for curing, and at
effective processing cost. It can be used with a wide range of
materials, both woven and non-woven, covering a wide range of
materials. This includes standard synthetics such as polyester, nylon,
polypropylene, high performance fabrics such as Nomex™ and
Kevlar™, as well as natural fibers such as silk and wool.
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Gregory Roche
Outline
 What is plasma?
 Types of plasma equipment
 Examples of fabric treatments
 Future Possibilities
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What is a “plasma”?
Plasma is considered “The 4th Phase of Matter”, and is
basically ionized gas. It is made up of ions, electrons and
neutral species. Some of these species are chemically active.
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What Type of Plasma?
There exists in nature a
wide range of plasmas,
from the Sun to the Aurora
Borealis. Processing
plasmas, those used for
treatment of materials are
similar in nature to “Neon
Sign” plasma.
“Neon Lights”
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The image above is of “Electron temperature” vs.
density. Processing plasmas are considered nonthermal; the neutral gas molecules are not as hot as the
electrons.
Gregory Roche
Plasma Equipment: Vacuum versus Atmospheric Pressure
Vacuum
Pro’s
Con’s
Good control of process
Vacuum systems capital
environment
cost and maintenance
Can control substrate
Issues with inline
impact
processing
Long life active species
Atmospheric
Pressure
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Lower cost hardware,
Short lifetime active species
maintenance
(1mm)
Works inline
Less control of environment
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Plasma Equipment: Common Atmospheric Plasma Systems
Corona
Pro’s
Con’s
More physical
change
greatest risk of
arc
Less uniform
Dielectric
barrier
discharge
More uniform
plasma
Lower reaction
rate
Atmospheric
plasma jet
Higher reaction
rate
Newest tech
Corona
DBD
uniform
Note that the Corona and DBD have the fabric run
between electrodes. In the APPJ configuration the fabric is
run outside of the electrode region.
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APPJ
Atmospheric Pressure Plasma Jet (APPJ)
Activated species are created between electrodes, and then blown
down on to the substrate. Design variations can include materials,
driving frequency, and gas mixture.
Driven at 13.56MHZ RF, the Helium-dominated
“flame” ~75C
Taken from: C. Tendero et al, “Atmospheric Pressure Plasmas: A review”, Spectrochimica Acta
Part B 61 (2006) 2-30
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Atmospheric Plasmas for Surface “Functionalization”
Plasma treatment is to the surface of the substrate only.
Treatment Objective
Plasma Process “Knob”
 Cleaning
 Ablation
 Wettability
 Sterilization
cleaning

Etching, roughening
 Change Bond
 Adhesion

 Finishing
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
create C=O, or C-NH
 Activate surface

Anti-microbial

Repellency

Moisture Management

Anti-static

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“Free radicals”
 Deposit

In-plasma

Deposit/Cure
Plasma Surface Modification
http://www.astp.com/plasma-equipment/applications
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Surface roughening
APPJ He/O2.
SEM images of wool
fibers. (a) untreated. (b-d)
increasing doses of
downstream plasma.
Surface contact angle
for conditions above.
“Influence of atmospheric pressure plasma treatment on various fibrous materials: Performance
properties and surface adhesion analysis”, Cheng, SY et al
http://www.sciencedirect.com/science/article/pii/S0042207X10000369
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Anti-microbial Plasma treatment Example
Fabric: Non-woven polypropylene
Treatment: DBD Helium Plasma pre-treat/cure of antimicrobial agent
(Left) AM plasma treated
(Right) Control showing spiral bacterial
growth. (AATCC Test 100-2004 Assessment of Antimicrobial Finishes)
Analysis showed that the AM Agent grafted to the fabric. The plasma cleaned the
surface and activated surface free radicals, which then reacted with the AM Agent as
it was applied.
C. Cornelius Doctoral Dissertation, NC State,2009
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Wicking example
DBD-He plasma treatment
on jute fibers: changes to
surface chemistry and
topography as shown in
wicking time and
roughness/adhesion
measures.
Abdullah A. Kafi, Kevin Magniez, Bronwyn L. Fox, A surface-property relationship of atmospheric
plasma treated jute composites, Composites Science and Technology, Volume 71, Issue 15, 24
October 2011, Pages 1692-1698, ISSN 0266-3538
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Adhesion example
 DBD He plasma treatment of Jute (as previous, Kafi et al) showing correlation
between plasma treatment, surface roughness, and adhesion.
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ApTex™: Roll-to-Roll Full 72” fabric @NC State
RF
Match
Fabric feed
Electrode assy
Chill
roller
RF
Supply
Fabric take up
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Example APPJ “linear” source
RF electrode
plasma
G
G
G
G
G
“Downstream” region
Fabric
72”
View looking up,
through fabric
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G
G=ground
electrode
View looking towards fabric exiting
plasma region (this tool runs 10”
fabric)
• Run electricity between electrodes to
create the plasma.
• Activated species are blown onto the
fabric
Bottom view
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Plasma Pre-Treatment: Hydrophilic
APPJ He/O2: non-woven polypropylene
Untreated shows water repellency
Treated shows water absorbency
ASTM D7334 - 08 Standard Practice for Surface Wettability of
Coatings, Substrates and Pigments by Advancing Contact Angle
Measurement
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Plasma Induced Polymerization Sequence
Monomer
1.
2.
Initiation: Plasma-generated specie gives it’s energy
to a monomer
Propagation (chain reaction): The monomer uses that
energy to create a bond to another monomer, and
passes on the energy. Monomers bond together to
form a polymer.
Functional
chemistry
Polymer
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19
Post Treatment: Plasma cured DWR stain test results
•Fabric was treated with repellent finish.
•Stain materials applied & removed as per test method.
•Examined as per test method
AATCC Test
Method 130
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Post Treatment: AATCC TM 130 Soil Release Ratings
Synthetic Woven Fabric
1
3.5
4.0
5.0
3.0
5.0
4.0
3.5
2
3.0
3.5
5.0
3.0
5.0
4.0
4.0
1
3.5
4.0
5.0
3.0
4.5
3.5
4.0
2
3.0
3.5
5.0
3.0
5.0
3.5
4.5
3.3
3.8
5.0
3.0
4.9
3.8
4.0
Observer
Ketchup
Mustard
Grape Juice
Cooking Oil
Red Wine
Suntan Oil
Suntan Lotion
1
5.0
5.0
5.0
3.5
5.0
4.5
5.0
2
5.0
5.0
5.0
4.0
5.0
5.0
5.0
3
5.0
5.0
5.0
4.0
5.0
5.0
5.0
5.0
5.0
5.0
3.8
5.0
4.8
5.0
control
control
Average Grade
Specimen
A
Average Grade
A “5” means “no discernable stain”.
Net result is improvement to stain resistance for all materials.
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AATCC TM 22 Spray Test Natural Fibers
Silk
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Wool
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Soiling Prevention: Polyester/spandex knit
As Received
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APPJ Finish
Durability of Plasma-Cured DWR: Oleophobicity
Polyester woven: plasma cured
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Durability of Plasma-Cured Alcohol/Water Repellent
Polyester woven
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Other …future possibilities
 Plasma used to modify surface so as to graft to

Anti-static

Fire retardant

Drug delivery agents

Blood filtering agents

Insect repellent

Perfumes
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END
 Thank you for your attention!
Questions or comments: [email protected]
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Backup slides
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Functionalization of non-woven polypropylene for grafting of biological materials
Here the PP substrate was activated for grafting to an Anticoagulent Agent (heparin)
through a three-step atmospheric plasma treatment. The photos below show the results of
the optimized conditions, showing a homogeneously spread coating.
Figure 9 from Anticoagulant and antimicrobial finishing of non-woven polypropylene textiles
S Degoutin et al 2012 Biomed. Mater. 7 035001 doi:10.1088/1748-6041/7/3/035001
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Improved bonding strength in adhesives
Atmospheric plasma treatment of
composite and ply adhesive.
Findings are that newly formed
carboxyl groups on the surface of
the composite and the epoxide
groups within the adhesive lead
to increase bonding strength.
http://www.aero.org/publications/crosslink/spring2011/irnd.html
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Gregory Roche