1. SURFACE CHARACTERIZATION AND HYSTERISIS STUDIES
ON PLASMA MODIFIED POLYMER SURFACES
Authors: Shaila Thakur, Manisha Choudhary, Sudarsan Neogi Department of Chemical Engineering, Indian Institute Of Technology, Kharagpur
ID of Authors:
Chemference’12
INTRODUCTION
3) FOURIER TRANSFORM INFRARED RADIATION
RESULTS
Plasma is the "Fourth State of Matter“containing a significant number of electrically charged particles.
Plasma can be generated in several ways. The plasma generated by electric filed are divided into DC, RF and Microwave plasmas.
Desired effects are achieved by ionic bombardments on the sample surface.
1) HYSTERESIS STUDY:
Parameter
Values
Power
100 watt
Pressure
150 militorr
Gas flow rate
20 sccm
Treatment time
5 min .
FIG 3(a): Graph of water contact angle vs time for Ar plasma treated PVC
FIG 5: FTIR of Ar treated and untreated Polycarbonate.
FIG 1 : PLASMA GENERATION IN A GLASS BALL.
4) SCANNING ELECTRON MICROSCOPE
OBJECTIVE
To analyze the effect of plasma treatment on polymer surfaces and study the changes in wettability, chemical composition and surface morphology of plasma treated samples.
PROCEDURE
The polymer samples are cut and cleaned using acetone for PP and PVC and isopropyl alcohol for PC.
After an ultrasound cleaning and drying, the samples are introduced in the PECVD reactor (shown below) for plasma treatment of the exposed surface.
Owens and Wendt method:
0.5(1+cosθ)(l/√ld)= (√ lp/ld)*(√sp)+ √ sd
FIG 6(a): Untreated Polycarbonate
FIG 6(b) : O2 treated Polycarbonate
FIG 3(b): Graph for surface energy calculations of samples.
2) OPTICAL EMISSION SPECTROSCOPY
CONCLUSION
The wettability studies of PC,PP and PVC showed that:
The contact angle values decrease
Surface energy values increase for all treated conditions with three different gases in RF plasma. This proved that hydrophilicity is improved.
FTIR of Ar treated Polycarbonate shows the effect of bond breakage and hydrogen abstraction can be seen from the decreased absorbance of peaks.
SEM agrees with the contact angle results by exhibiting increased surface roughness.
FIG 4(a) : OES of Ar plasma without sample
FIG 2 :DIGITAL IMAGE OF THE EXPERIMENTAL SETUP-
THE PECVD REACTOR
REFERENCES
N. Gomathi, Sudarsan Neogi (2009). Surface modification of polypropylene using argon plasma: Statistical optimization of the process variables. Applied Surface Science, 255, 7590–7600.
Wei Zhang, Paul K. Chu, Junhui Ji, Yihe Zhang, Xuanyong Liu, Ricky K.Y. Fu,Peter C.T.Ha, Qi Yan (2006). Plasma surface modification of poly vinyl chloride for improvement of antibacterial properties. Biomaterials, 27, 44–51.
3) The reactor chamber was evacuated to 10-3 mbar with a rotary-roots pump assembly.
4) Argon gas was introduced into the chamber through the mass flow controllers. The desired parameters are set and the reactor is switched to RF mode.
5) Plasma is generated between the electrodes for the set time and the various runs were performed for 3 different gases and samples.
FIG 4(b) : OES of Ar plasma with PVC sample.