Light Scattering Study of Polymer Hydro Gel Nano Particles
Transcript of Light Scattering Study of Polymer Hydro Gel Nano Particles
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BY
Ashar A Z Shanmuga Vadivu V
Under the Guidance of
Dr B V R Tata
Brijitta J
LIGHT SCATTERING STUDY OF POLYMERHYDROGEL NANOPARTICLES
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INTRODUCTION
Gels: Three dimensional polymer network dispersed
in a homogeneous medium.
When the homogenous medium is water, these are
called as Hydrogels
Stimuli responsive hydrogels:Hydrogels that
respond to changes in environmental conditions
like temperature,pH,metal ions etc..
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OBJECTIVE
Synthesis of Macro and Microgels
Crystallization of the Microgels
Characterization using Dynamic and Static
Light ScatteringPart 1:Synthesis-Crystallization
Shanmuga Vadivu VPart 2:Characterization studies using Light scattering
Ashar A Z
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MACROGEL
Macrogel is continuous
polymer network
It is transparent
It doesnt flow
MICROGEL
Each microgel particle is
composed of randomly
oriented polymer chain
cross linked into a
network structure
Turbid and is due to the
particle formation
It flows
MicrogelMacrogel
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SYNTHESIS OF POLY NIPAM
MACROGEL
NIPAM+BIS+KPS+TEMED
At room temperature under
Argon purged condition for
5 minutes
Gel formed within 5minutes
of Argon bubbling
MICROGEL
NIPAM+BIS+SDS+KPS
At 70C under Argon
purged condition for
4 hours
Cooled and the microgels
were purified by dialysis
before annealingafter annealing
Macrogel
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THERMORESPONSIVE MACROGEL
40C
25C
Collapsed gel
Water
Macrogel expels out its water content (deswelling) above the
VPT~32C and it swells at room temperature.
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CRYSTALLIZATION OF MICROGEL
The synthesized microgels were putin dialysis bag for removing theimpurities
The sample was centrifuged andannealed from 25C to 40C
Ion-exchange resins were added for
further purification The sample showed iridescence
under white light illumination
Iridescence implies crystallization
SLS studies were carried on thecrystallized sample to determine thevolume fraction
Crystals
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CHARACTERIZATION USING LIGHT
SCATTERING
Particle size determination using DLS and SLS
Three samples of varying volume fraction were
prepared
Static light scattering measurements were carried out on
these samples to study their Gas, Liquid and Crystalline
order
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GAS LIKE ORDER
0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.00.045
0.050
0.055
0.060
0.065
0.070
0.075
0.080
0.085
1/P(q)(arb.Units)
q2(10
10cm
-2)
0.5 1.0 1.5 2.0 2.5 3.0 3.5
0
5
10
15
20
I(q)(arb.Units)
q(105cm
-1)
0.5 1.0 1.5 2.0 2.5 3.0 3.50
5
10
15
20
25
30
E(
in
arb.unit
s)
q (x105)cm
-1
Transparent sample
S(Q) plot is flat andhence Gas like order
Gas Sample
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LIQUID LIKE ORDER
1.0 1.5 2.0 2.5 3.0 3.5
0
1
2
3
4
5
6
7
8
I(q)(a
rb.u
mits)
q(10
5
cm
-1
)
Liquid like sample
=110
=0.064
( )[ ]
2
2
2sin4
3max
max
q
n
q
p =
=
6
3pnd =
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I(q)(10
3arb.units)
q(105cm -1)
Bragg spots
CRYSTALLINE ORDER
=122
=0.079
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( ) ( )]( )42
222640 2116
r
aII
+=( ) ( ) ( ) ] ( )drqrrgrqnqS p sin141
0
( ) ( ) ( )) ( ) ] 23cossin3 qaqaqaqaqP ( ) ( ) )3exp 2qRqI g
0.5 1.0 1.5 2.0 2.5 3.0 3.5
2
4
6
8
10
12
14
16
18
20
22
24
q2(10
10cm
-2)
P(Q)(arb.units)