Inda Presentation Roche Final April 2012

Recent Advances in Atmospheric Plasma
Treatment of Textiles

Gregory Roche, Carrie Cornelius, Wade Tyner
ApJet, Inc.

INDA CAB 2012 Gregory Roche

Abstract

Ø 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.


Outline

Ø What is plasma?
Ø Types of plasma equipment
Ø Examples of fabric treatments
Ø Future Possibilities


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.


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.

The image above is of “Electron temperature” vs.
density. Processing plasmas are considered non-
“Neon Lights” thermal; the neutral gas molecules are not as hot as the
electrons.

Plasma Equipment: Vacuum versus Atmospheric Pressure

Pro’s Con’s

Vacuum Ø Good control of process Ø Vacuum systems capital
environment cost and maintenance
Ø Can control substrate Ø Issues with inline
impact processing
Ø Long life active species

Atmospheric Ø Lower cost hardware, Ø Short lifetime active species
maintenance (1mm)
Pressure
Ø Works inline Ø Less control of environment


Plasma Equipment: Common Atmospheric Plasma Systems

Pro’s Con’s
Corona More physical greatest risk of
change arc
Less uniform Corona
Dielectric More uniform Lower reaction
barrier plasma rate
discharge
Atmospheric Higher reaction Newest tech DBD
plasma jet rate
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. APPJ


Example DBD Hardware

Commercial DBD systems are typically some variant of this
schematic. Corona systems are similar as well, with the difference
being that no insulator covers the electrodes.
Figure taken from: U. Kogelschatz, “Dielectric-barrier discharges: Their History, Discharge Physics, and
Industrial Applications”, Plasma Chemistry and Plasma Processing, Vol 23, No. 1 March 2003


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


Atmospheric Plasmas for Surface “Functionalization”

Plasma treatment is to the surface of the substrate only.

Treatment Objective Plasma Process “Knob”
Ø Cleaning Ø Ablation
q cleaning
Ø Wettability
q Etching, roughening
Ø Sterilization
Ø Change Bond
Ø Adhesion q create C=O, or C-NH
Ø Finishing Ø Activate surface
q Anti-microbial q “Free radicals”
q Repellency
Ø Deposit
q Moisture Management
q In-plasma
q Anti-static
q Deposit/Cure


Plasma Surface Modification

http://www.astp.com/plasma-equipment/applications


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

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

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


Adhesion example

Ø DBD He plasma treatment of Jute (as previous, Kafi et al) showing correlation
between plasma treatment, surface roughness, and adhesion.


ApTex™: Roll-to-Roll Full 72” fabric @NC State

Fabric feed RF
Match

Electrode assy RF
Chill Supply
roller

Fabric take up


Example APPJ “linear” source
RF electrode
plasma
G G G G G G G=ground
electrode
“Downstream” region
Fabric

72” 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
View looking up,
through fabric fabric
Bottom view


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


Plasma Induced Polymerization Sequence

Monomer
1. Initiation: Plasma-generated specie gives it’s energy
to a monomer Functional
2. Propagation (chain reaction): The monomer uses that chemistry
energy to create a bond to another monomer, and
passes on the energy. Monomers bond together to
form a polymer.

Polymer 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


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
control
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
control
2 3.0 3.5 5.0 3.0 5.0 3.5 4.5

Average Grade 3.3 3.8 5.0 3.0 4.9 3.8 4.0

Specimen 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

A 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

Average Grade 5.0 5.0 5.0 3.8 5.0 4.8 5.0

A “5” means “no discernable stain”.
Net result is improvement to stain resistance for all materials.


AATCC TM 22 Spray Test Natural Fibers

Silk Wool

Soiling Prevention: Polyester/spandex knit

As Received APPJ Finish


Durability of Plasma-Cured DWR: Oleophobicity
Polyester woven: plasma cured


Durability of Plasma-Cured Alcohol/Water Repellent

Polyester woven


Other …future possibilities

Ø Plasma used to modify surface so as to graft to
q Anti-static
q Fire retardant
q Drug delivery agents
q Blood filtering agents
q Insect repellent
q Perfumes


END

Ø Thank you for your attention!

Questions or comments: greg.roche@apjet.com


Backup slides


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


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


Inda Presentation Roche Final April 2012

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