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ficient energy to induce cleavage of the chemical bonds in membrane structure and to
form macromolecule radicals, which subsequently initiate graft copolymerization [25].
Plasma treatment can be done by either regular plasma treatment, or plasma graft
copolymerization (PGC) [26].
Various plasma components such as electrons, ions, radical etc. are involved in
this process. These components react on exposed surfaces. Since some parts of the
surface are exposed to energies higher than the characteristic bond energy of polymers,
these parts undergo scission reactions and form new bonding configurations on the sur-
face [27]. Plasma treatment of polymer surface causes not only a modification during
the plasma exposure, but also leaves active sites on the surfaces which are subjected to
post-reaction [28]. Glow-discharge plasma technique is particularly useful for functiona-
lization of surfaces as it is possible to modify outermost surface layer by this technique
[15, 29]. These factors improve the adhesion properties of the surface [30].
In this paper we have synthesized polymer nanocomposites using Co NPs and
Poly Methyl Meth Acrylate (PMMA). These materials were exposed to Ar plasma, and
modification in the surface and chemical properties was investigated.
Materials and methods. In the present study Co NPs were synthesized using
Menthaarvensis (pudina) plant extract. The plant was washed with sterile distilled water.
The plant extract was prepared by taking 25 g of thoroughly washed plant material in a
250 ml Erlenmeyer flask with 100 ml of distilled water, and then boiling the mixture
for 10 min in a water bath. The leaf broth was cooled and filtered through Whatman
No.1 filter paper (pore size 25 mm). For preparation of Co nanoparticles, 10 ml of the
prepared plant extract was added to 90 ml of 1 mM cobalt nitrate solution and incubated
in a rotary shaker for 2 h. The color of the solution changed from light yellow to brown
indicating the formation of Co nanoparticles [31].
PMMA granules were obtained as commercial grade from Loxim Polymers,
Jaipur) and used to prepare flat sheet membranes by the solution cast method. PMMA
granules were weighed and dissolved in dichloromethane (CH 2Cl 2) to prepare a 10%
solution. The solution was stirred by a magnetic stirrer to ensure the uniform dissolution
and to enhance the rate of dissolution at room temperature for about 5 h. The 5% Co
nanoparticles (of PMMA) were dispersed in the solvent dichloromethane using ultra-
sonicator. This dispersed solution was added to the PMMA solution and stirred for about
30 min. The solution was put into flat-bottomed petri-dishes floating on mercury to
ensure a uniform structure of membranes. The Solvent was allowed to evaporate slowly
over a period of 10…12 h. The films so obtained were peeled off using forceps [32].
The plasma treatment device consisted of a source chamber with complete power
supply, connected to a vacuum system. A magnet is positioned to get a magnetic field
(0.5 K Gauss) inside the source chamber. Argon gas, used to generate plasma, was
admitted into the source chamber using a flow controller and applying DC power
between two electrodes. The confined plasma in the chamber was employed for surface
modification. Applying a high voltage between two electrodes with magnetic field
generated the DC glow discharge. The current in the upper and lower electrodes was
maintained at few mA and 3.2 KeV. In this study Arplasma was used. The plasma was
almost homogenous in a low-pressure glow discharge. The reaction chamber was
evacuated and then refilled with low-pressure Ar gas to create glow discharge plasma.
Plasma was energized by direct current. Other energetic species in plasma include
radicals, electrons and meta-stable photons in short-wave UV range.
UV-Vis spectrum of NPs was taken using UV-Vis spectrophotometer SHIMADZU
1800. FTIR Analysis was done using FTIR spectrophotometer (IR Affinity-1 Shi-
–1
madzu) in the range of 4000…400 cm for knowing the possible functional groups
present with synthesized Co NPs. Scanning Electron Microscopic (SEM) analysis was
done using Scanning electron microscope (Carl ZEISS EVOR-18) operated at 20 kV.

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