Aatcc Meeting 2008 Khk

8/6/2019 Aatcc Meeting 2008 Khk

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Plasmas are generated in gases by heating, byapplying a voltage, or by injectingelectromagnetic waves.

Electrical discharges commonly used

Generation of Plasma


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The ignition is brought about by the small fraction

of charged particles always present in the gas.


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Emission of characteristic

glow when it comes to

ground state

Electron interactions in plasma


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PROPAGATION

GENERATION

LOSS OFELECTRONES


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Plasma Species determine the plasma type

Electron density

Ion density

Electron/ion temperatureInteractions between electron-electron, ion-

electron, ion-ion etc are possible

Plasma exhibit broad range of spectrum i.e

electron density from few to 1025

/cm3

Different mean path length


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System pressure

Electrode configuration

Nature of gasFlow rate of gas

Power

Time of treatment

Nature of substrate

PLASMA PROCESS PARAMETERSPLASMA PROCESS PARAMETERS


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PLASMA Dependency on System Pressure

To initiate and sustain the plasma

continuous supply of energy is must.

Vb= f (p .d)

At fixed applied voltage, d must decrease, as weincrease the pressure


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Electrode configuration and features

Presence of DielectricPresence of DielectricBarrierBarrier

Spacing between theSpacing between the

electrodeselectrodes

Geometry ofGeometry of


Symmetry ofSymmetry of



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The type of gas determines the nature of interactionbetween the substrate and the plasmai.e. etching, grafting, polymerisationBreakdown energy necessary to produce plasma varies

Inert gasesInert gasesHe, Ar are commonly used .These are used for cleaning, activation purposeThey act as diluting media for reactive gas

Oxygen containing plasmaOxygen containing plasma:Importance of reactive gas in surface modificationscan react with wide range of polymersImpart various functional groups like c-o, c=o, o-c-o,c-o-o etc

Types of Gas UsedTypes of Gas Used


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Fluorine containing plasmaFluorine containing plasma :CFx etching and polymerisation

HydrocarbonsHydrocarbons : methane, ethane, ethylene to generate plasma polymerised

hydrocarbon film to impart microhardness, optical refractive index and

impermeability

Organosllicone monomers :

excellent thermal and chemical resistance

Nitrogen containing plasma to improve wettability, printability

biocompatibility of the substrate

Types of Gas Used contd..Types of Gas Used contd..


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Why Helium in glow discharges?

Media for uniform glow discharge and carrier of

reactive gases

Mean free path

Possibility of collisions

Meta stable state configuration

Simple energy levels

Thermal conduction properties support theuniform discharge


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Discharge power SupplyDischarge power SupplyThe energy required to generate plasma depend on

the nature of gas and equipment

Higher power means high kinetic energy of the

reactive speciesOptimization depends with the substrate and

system parameters

Duration of treatment

The extent of treatment can be varied with time


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Polyester/cotton blended textiles

Why treatment of P/C blended textiles?

Treatment carried out at Textile Chemistry,Science and Engineering department of NCSU,

Raleigh, USA.

Hydrophilic textiles with AtmosphericHydrophilic textiles with AtmosphericPressure PlasmaPressure Plasma


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ObjectivesObjectives

1. To impart hydrophilicity to the textiles withatmospheric pressure plasma

2. To assess the effect of plasma treatment withmeasurement of wicking behaviour and surface

characteristics3. To study influence of following process variables

Intensity of Glow Discharge (Power Supply)Duration of Treatment

Nature of GasGas concentration (Flow rate)Distance between substrate and electrode


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Fabric: Polyester/cotton blended RFD fabric

Blend composition 67/33

epi / ppi : 90/70GSM: 88

Machine: Atmospheric Pressure Glow Discharge

at RF 13.56 MHz

Materials and methods


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Atmospheric Pressure Glow Dischargeat RF 13.56 MHz

RF generator

Electrodes

Gas input

Evaporator

Cooling for

system


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Assessment of Efficiency of Hydrophilic Treatment

Capillary rise up to 30 min

Interval of measurement of height-every

5 min.


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He : 40 LPMHe : 40 LPM

OO22 : NIL: NIL

D: 0.13D: 0.13

T: 25 secT: 25 sec

Height of capillary rise (cm)

wicking time 5 min 10 min 15 min 20 min 25 min 30 min

Discharge

Intensity

(Watts)

C 0.4 0.9 1.4 1.7 2.1 2.4

400 0.6 1.35 1.85 2.5 2.9 3.3

500 0.9 1.65 2.35 2.85 3.45 3.95

600 0.9 2 2.7 3.4 4.3 5700 0.85 1.5 2.6 3.35 4.1 4.8

Discharge Intensity v/s Wicking HeightDischarge Intensity v/s Wicking Height


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Role of Discharge Intensity of He Plasma with ORole of Discharge Intensity of He Plasma with O22


Wicking time 5 min

10min

15min

20min

25min

30min

Intensity of

Discharge

(Watts)

C 0.4 0.9 1.4 1.7 2.1 2.4

400 2.3 3.35 4.25 4.95 5.45 6.1

500 2.45 3.45 4.3 5.35 5.95 6.6

600 3.2 4.55 5.35 5.9 6.3 7

700 3.6 4.55 5.4 6.05 6.6 7.1


O2 : 0.15 LPMO2 : 0.15 LPM

D: 0.13D: 0.13

T: 25 secT: 25 sec

effect of o er on ca i ary rise

0

1

2

3

45

6

7

400 500 600 700

Po er (Watts)

HeightofCa

iary

ise(c

5 min

10 min15 min

20 min

25 min

30 min

n


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Wicking time 5 min 10 min 15 min 20 min 25 min 30 min

Treatment

Time

(sec)

C 0.4 0.9 1.4 1.7 2.1 2.4

14 0.5 0.95 1.55 1.9 2.4 2.7

20 1.1 2.1 2.9 3.75 4.6 5.3

25 1.5 2.55 3.35 4.2 4.8 5.35

37 2. 4 4.1 5.4 6.4 7 7.7


O2 : NILO2 : NIL

P: 650 wattsP: 650 watts

D: 0.13D: 0.13

Effect of Duration of TreatmentEffect of Duration of Treatment

Helium Plasma inHelium Plasma in

absence ofabsence ofoxygenoxygen

effect of treatment time on capilary rise

0

1

2

3

4

5

6

7

8

9

C 14 20 25 37

treatment time (sec)

HeightofCapilary

Rise(cm)

5 min

10 min

15 min

20 min

25 min

30 min


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Treatment

time

(sec)

C 0.4 0.9 1.4 1.7 2.1 2.4

14 1.1 2.2 3.3 4.3 5 5.85

20 1.6 2.9 3.7 4.6 5.3 5.9

25 2 3.7 4.7 5.65 6.15 6.6

37 2.65 3.8 5 5.8 6.4 7.5


O2 : 0.15 LPMO2 : 0.15 LPM

P: 650 wP: 650 w

D: 0.13D: 0.13

Effect of Duration of Treatment in Presence of OEffect of Duration of Treatment in Presence of O22

Helium Plasma inHelium Plasma in

presence ofpresence ofoxygenoxygen

effect of treatment time on capilary rise

0

1

2

3

4

5

6

7

8

C 14 20 25 37

treatment time (sec)

HeightofCapilaryRise(

5 min

10 min

15 min

20 min

25 min

30 min


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He flow rate

LPM

13 0.65 1.9 2.4 3.15 3.7 4.1

22 1.5 2.4 3.4 3.8 4.2 4.6

30 2 3.5 4.45 5.15 5.6 6.15

40 1.4 2.6 3.65 4.4 5 5.5

50 1.2 2.1 2.9 3.3 4.45 4.9

60 0.7 1.4 2.3 3.1 3.5 4

P: 650 w

O2 : NIL

D: 0.13

T:25 sec

Effect of Gas Concentration

He plasma in

absence ofoxygen

effect f l te

0

1

2

3

4

5

6

7

13 22 31 40 52 60

Gas l

ate ( )

ei

t

f

apilar

ise(cm)

5

i

10

i

15

i

20

i

25

i

30

i


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Height of capillary rise(cm)

wicking time

5

min 10 min 15 min 20 min 25 min 30 min

He flow rate

LPM

30 2 2.9 3.6 4.1 4.5 4.9

40 2.4 3.4 4.3 5.1 5.7 6.3

50 2.7 3.8 4.9 5.5 6 6.560 2.45 3.35 4.4 4.9 5.45 5.8

P: 650 w

D: 0.12

T:25 sec

O2 : 0.15 LPMO2 : 0.15 LPM

Effect of Gas Concentrationwith Oxygen

Helium Plasma inHelium Plasma inpresence ofpresence ofoxygenoxygen

e ec Gas Ra e

0

1

2

3

4

5

6

7

35 40 52 60

Gas

Ra

e

P

He

Ca

ay

Rse

c

5 !"

n

10 !"

n

15 !"

n

20 !"

n

25 !"

n

30 !"

n


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Electrode

distance

(inch)

0.10 2.5 3.6 4.5 5.5 6.2 6.6

0.11 2.1 3.1 3.8 4.4 5 5.7

0.12 1.2 2.2 3 3.7 4.3 4.9

0.13 0.9 1.85 2.6 3.4 4.1 4.70.14 0.8 1.7 2.4 3.3 4 4.6

0.15 0.7 1.4 2 2.6 3.1 3.8

effect of Electrode distance

0

1

2

3

4

5

6

7

0.10 0.11 0.12 0.13 0.14 0.15

Electrode istance (inch)

Heightof

apilaryRi

se(cm)

5 min

10 min

15 min

20 min

25 min

30 min

P: 600 W

He: 40

T: 25 sec

Effect of Distance between Substrate andElectrode


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Height of capillary rise(cm)wicking time 5 min 10 min 15 min 20 min 25 min 30 min

Electrode

distance

(inch)

0.11 3.1 4.4 5.3 5.9 6.5 6.95

0.12 2.6 3.7 4.5 5.15 5.55 5.9

0.13 2.2 3.3 4.3 4.9 5.4 5.7

0.14 2 2.6 3.6 4.25 4.7 5.1

effect of Electrode distance

0

1

2

3

4

5

6

7

0.11 0.12 0.13 0.14

Electrode Distance (inch)

HeightofCapilaryRise(cm)

5 min

10 min

15 min

20 min25 min

30 min

P: 600 WP: 600 W

O2 : 0.15 LPMO2 : 0.15 LPM

P: 600P: 600

Effect of Electrode SpacingEffect of Electrode Spacing

Helium Plasma inHelium Plasma inpresence ofpresence ofoxygenoxygen


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Gas composition and Power AppliedGas composition and Power Applied

0

1

2

3

4

400 500 600 700

powe applie wa s

wickingheight(cm

with e iu on

with e iu and gen


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Gas composition and Duration of TreatmentGas composition and Duration of Treatment

0

0.5

1

1.5

2

2.5

3

14 20 25 37

time o treatment sec

ic

kingheiht

cm)

i h eliu onl

i h eliu and O gen


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0

0.5

1

1.5

2

2.5

33.5

0.11 0.12 0.13 0.14

electrode distance) inch)

wickingheight(c

with Helium only

with Helium and Oxygen

Gas composition and electrode spacingGas composition and electrode spacing


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Plasma treatment can modify the textile surfacePlasma treatment can modify the textile surfaceto impart the hydrophilic propertiesto impart the hydrophilic propertiesIncrease in duration of treatment and intensityIncrease in duration of treatment and intensityof Plasma led to more hydrophilicityof Plasma led to more hydrophilicity

Increase in Gas flow rate showed initially increaseIncrease in Gas flow rate showed initially increasein hydrophilicity and then decreasein hydrophilicity and then decreaseAt given applied power (Intensity), the increase inAt given applied power (Intensity), the increase inelectrode spacing has negative effect onelectrode spacing has negative effect onhydrophilicityhydrophilicity

Addition of little amount of oxygen hasAddition of little amount of oxygen hassignificant effect on the hydrophilic propertiessignificant effect on the hydrophilic properties

Concluding RemarksConcluding Remarks


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Aatcc Meeting 2008 Khk

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