Carbon nanoparticle containing responsive hydrogel … · Polymer Hydrogels IUPAC: Non-fluid...

Carbon nanoparticle containingresponsive hydrogel composites

Barbara Berke

Supervisors: Orsolya Czakkel (ILL)

Krisztina László (BME)

All You Need Is Neutrons – 17/05/2016

Polymer Hydrogels

IUPAC: Non-fluid polymer network that is expanded throughout its whole volume by a fluid.

• Solid, three dimensional polymer network filled by air (aerogels) or liquids (liogels) water (hydrogel)

• Amphiphilic polymer chains must be kept together

first order bonds: chemical gels (monomer + cross-linker are needed)

second order bonds: physical gels

2

Introduction Synthesis Macroscopic Responsivity Neutrons Summay

High absorption capacity and soft character

3

Non-linearchange upon

environmentalstimuli.

Introduction Synthesis Macroscopic Responsivity Neutrons Summary

Stimuli-responsive (intelligent) hydrogelsControlled drug delivery

Tissue engineering

Actuators

Microfluidics

Sensors

Intelligent polymer

4

Problems: weak mechanical properties, fracture upon repetitive usage, etc.

tuned response is needed

• Collapsing near human body temperature

Volume phase transition temperature (VPTT) (~34 °C)

• Excellent swelling properties (~30-40 times of dry weight)

• Almost completely reversible deformation

• Biocompatible ?!

Possible solution: Composite preparation


Poly(N-isopropylacrylamide) – PNIPA

http://brm.technion.ac.il/gallery/

5

Multi-walled

carbon nanotubes (CNT) Graphene oxide(GO)Good mechanical properties

IR sensitivity

Potentially tunable electrical

and thermal conductivity,

magnetic sensitivity

Dispersibility

functionalisation

Toxicity ?

Oxidised by cc. HNO3 Improved Hummers method


Carbon nanoparticles (CNP)

graphene

Keresztkötő-sűrűség:

6

150molNIPA

mol BA

Nomenclature:

X mg GO/ g monomer –

GOX@PNIPA


CNT and GO@PNIPA compositesNIPA BA

N-isopropylacrylamide N,N’ methylenebisacrylamide

N,N,N’,N’ –

tetramethylethylenediamine

ammonium persulfate

water

Filler-free gel

GO suspension

Gel synthesis

GO@PNIPA

CNT suspension - aggregates

Gel synthesis

CNT@PNIPA

CNT

containing

composite

GO

containing

composite

Cross-linking density:

Keresztkötő-sűrűség:

7

150molNIPA

mol BA

Nomenclature:

X mg GO/ g monomer –

GOX@PNIPA


CNT and GO@PNIPA compositesNIPA BA

N-isopropylacrylamide N,N’ methylenebisacrylamide

N,N,N’,N’ –

tetramethylethylenediamine

ammonium persulfate

water

Filler-free gel

GO suspension

Gel synthesis

GO@PNIPA

CNT suspension - aggregates

Gel synthesis

CNT@PNIPA

CNT

containing

composite

GO

containing

composite

Cross-linking density:

8

• Macroscopic lengthscale:

• Swelling degree

• Elastic modulus

• Microscopy

• Responsivity:

• Differential scanning calorimetry

• Temperature induced deswelling kinetics

• Microscopic lengthscale - Neutrons

• Small angle neutron scattering (SANS)

• Neutron spin-echo spectroscopy (NSE)


Characterisation

9


Microscopy

Digital optical

microscope

(DOM)

Scanning electron

microscope

(SEM)

CNT@PNIPA GO@PNIPAPNIPA

50 mm

10

[1] B. Berke et al.: Static and dynamic behaviour of responsive graphene oxide - poly(N-isopropyl acrylamide) composite gels. Submitted

[2] K. László et al. Macromolecules 2004, 37, 10067-10072; Chetty et al. – eXPRESS Polymer Letters Vol.7, No.1 (2013) 95–105

GO@PNIPA1 PNIPA from literature2

0 5 10 15 20 250

2

4

6

8

10

Ma

ss s

wel

lin

g d

egre

e (-

)

Mo

du

lus

(kP

a)

mg GO/g NIPA

20

25

30

35

40

200 150 100 500

2

4

6

8

10

Mass

sw

elli

ng d

egre

(-)

Mod

ulu

s (k

Pa)

Cross-linking density (mol/mol)

20

25

30

35

40

0 5 10 15 20 250

2

4

6

8

10

Ma

ss s

wel

lin

g d

egre

e (-

)

Mo

du

lus

(kP

a)

mg CNT /g NIPA

20

25

30

35

40

CNT@PNIPA


Swelling degree (at 20 °C) and elastic modulus

What kind of interactions are formed?

11

VPT did not change

The relative swelling degree does

not depend on the quality and

quantity of the filler.

20 25 30 35 40 45 500

20

40

60

80

100

CNT20@PNIPA

CNT5@PNIPA

GO5@PNIPA

GO20@PNIPAPNIPA

Rela

tiv

e s

well

ing

deg

ree (

%)

Temperature (°C)


Equillibrium responsive properties

Relative swelling degree (%):

𝑆𝑤𝑒𝑙𝑙𝑖𝑛𝑔 𝑑𝑒𝑔𝑟𝑒𝑒 𝑎𝑡 𝑇

𝑆𝑤𝑒𝑙𝑙𝑖𝑛𝑔 𝑑𝑒𝑔𝑟𝑒𝑒 𝑎𝑡 20 °𝐶× 100

12

0 5 10 15 20 25

50

55

60

65

70

En

thalp

y (

J/g

)

mg GO / g NIPA

200 150 100 50

50

55

60

65

70

En

thalp

y (

J/g

)

Cross-linking density (mol/mol)

[1] B. Berke et al.: Static and dynamic behaviour of responsive graphene oxide - poly(N-isopropyl acrylamide) composite gels. Submitted

[2] K. László et al. Macromolecules 2004, 37, 10067-10072;

VPTT: 33.8 °C

The enthalpy depends on the GO content.


Differential scanning microcalorimetry (DSC) – GO@PNIPA

20 25 30 35 40 45 50

0.2 mW

5GO@PNIPA

PNIPA

10GO@PNIPA

Hea

t fl

ow

(m

W)

Temperature (°C)

exo

20GO@PNIPA

GO@PNIPA1 PNIPA from literature2

Minta𝒎

𝒎𝟎 𝒇𝒊𝒏A1

t1

(min)p1 A2 t2 (min) p2

PNIPA 5.49 82.6 12.1 1.33 - - -

5GO@PNIPA 3.64 51.8 4.90 0.69 44.2 13301 0.53

10GO@PNIPA 7.14 33.6 3.56 0.50 59.1 4369 0.59

20GO@PNIPA 7.85 42.9 5.04 0.57 49.1 1317 0.70

13

21

1 2

( ) ( )

1 2

0 0

( )

ppx x

t t

fin

m mA e A e

m m

0.1 1 10 100 1000 10000 1000000

20

40

60

80

100

Rel

ati

ve

ma

ss (

%)

Time (min)

0 5 10 15 20 250

5000

10000

15000

t 2 (

min

)

mg GO / g NIPA

𝒎

𝒎𝟎 𝒇𝒊𝒏:final relative mass

A: preexponential constant

t: time constant

p: exponent

20 °C 50 °C


Time-dependent responsive behaviour – GO@PNIPA

14

0.1 1 10 100 1000 10000 1000000

20

40

60

80

100PNIPA

5GO@PNIPA

10GO@PNIPA

20GO@PNIPA

Rel

ati

ve

mass

(%

)

Time (min)

20 °C 50 °C


Time-dependent responsive behaviour

1 10 100 1000 10000 100000

40

60

80

100

PNIPA

3CNT@PNIPA

6CNT@PNIPA

12CNT@PNIPA

24CNT@PNIPA

Rel

ati

ve

dia

met

er

(%)

Time (min)

CNT@PNIPAGO@PNIPA

15


From macroscopic to microscopic lengthscales

(almost) all you need is neutrons

16


Small-angle neutron scattering- SANS

http://www.mirrotron.kfkipark.hu/images/SANS-concept.png

2 2

(0)( )

1

II Q B

Q

Ornstein-Zernike model

I(Q): intermediate scattering function

Q: scattering vector

I(0) and B: Q-independent constants

ξ: correlation length

ρ: fractal dimension of polymer coils

Component

Neutron scattering

cross-section

(10-6/Å2)

PNIPA, (C6H11NO)n 0.825

GO, C65O35 5.993

D2O 6.364

Samples swollen in D2O

at 25 °C

Measured on D22

17

Dynamic processes from 1 ps to ~100 ns

Diffusion, polymer solutions, gels, membranes, etc


Neutron spin-echo spectroscopy - NSE

Measured on IN11

18


NSE in swollen state (25 °C) - PNIPA

Simple exponential fit

Dynamics ~q2

Full decay (baseline=0)

Diffusive motion

( , )exp( )

( ,0)

I Q

I Q 2

diffD Q

6

Bdiff

H

k TD

𝐼(𝑄,𝜏

𝐼(𝑄,0: intermediate scattering function

G: relaxation rate

t: time constant

Ddiff: diffusion coefficient

kb: Boltzmann constant

T: absolute temperature

h: viscosity of the medium

ξH: hydrodynamic correlation length

19

CNT@PNIPA

Sample Ddiff1011 (m2/s) ξH (Å) ξ (Å)

PNIPA 7.03±0.14 28.4±0.01 92.0±1.09

5GO@PNIPA 7.41±0.24 26.9±0.08 90.0±1.11

20GO@PNIPA 8.10±0.30 24.6±0.90 66.7±0.67

GO20@PNIPA

Baseline ≠ 0

~2% 0.05

Summary of neutron results so far…


NSE in swollen state (25 °C) - composites

GO5@PNIPA

Baseline = ?

~0.5% ~0.005 - 0.01?

20


Summary

Regular PNIPA

cross-links

PNIPA cross-links

+ GO hypernodes

Effects on: CNT@PNIPA GO@PNIPA

Swelling, elasticity

Aggregations

Interactions weak strong

Response

VPTT

Enthalpy

Kinetics

Time constant

Architecture of the polymer matrix

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• NMR interactions between CNP and polymer?

• Mechanical tests

• Temperature-dependent structure & dynamics (SANS, NSE, SAXS, XPCS).

Other systems:

• Modification of the surface chemistry of the nanoparticles to influence the

interactions in the composites

• Pre-planned, application-oriented composite-preparation by tuning the quality and the

quantity of the nanoparticles.


Next steps

Acknowledgement

ILL PhD program

George Olah Doctoral School (BME)

OTKA K101861

TÁMOP-4.2.1/B-09/1/KMR-2010-0002

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Surface Chemistry Group

Dávid Kun

József Hári

Lionel Porcar

Dimitri Renzy

Mark Jacques

Krisztina László Orsolya Czakkel

Thank you for yourattention!

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Carbon nanoparticle containing responsive hydrogel … · Polymer Hydrogels IUPAC: Non-fluid...

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