light scattering study of polymer hydro gel nano particles

8/2/2019 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)

light scattering study of polymer hydro gel nano particles

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