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Layer by Layer Nanoarchitectures Assembled

from Alumina (Al2O3) and Zirconia (ZrO2) Systems

Kristan R. Moore1, 2, Tabbetha A. Dobbins1, 2, and Vimal Kamenini2

1 Dept. of Physics, Senior, Grambling State University2 Institute for Micromanufacturing, Louisiana Tech

University

Grambling State University

Introduction Planar substrate ConclusionColloidal substrate

• There is a research lacking in creating triple phase boundaries.• In creating these boundaries, there is a need to stabilize and control

them.• Using the layer-by-layer (LbL) technique allows:

– these boundaries to be stabilized and controlled– the concentration and deposition time to be studied to ascertain their

affect on the degree of control• This project will show that the morphology of these boundaries can

be controlled using the layer-by-layer (LbL) technique.• The positive controls in this experiment were:

– a fixed concentration of 2 mg/mL, and– a fixed deposition time of 10 minutes

• The negative control in this experiment:– the isoelectric points are unknown

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Sketch of Potential curves

1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9

1 2 3 4 5 6 7 8 9

Working pHWorking pH

Working pH

μm-Al2O3 nm-Al2O3

nm-ZrO2

ζ (mV)

pH

pHpH

ζ (mV)

ζ (mV)

Introduction Planar substrate Colloidal substrate Conclusion

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Layer-by-Layer Approach• Is the deposition of uniform multilayer thin films from

polyelectrolyte solutions.• During LbL nanoassembly, the film growth that

occurs is the result of Coulombic interactions between polymneric cations and anions.

• This assembly of alternating layers of oppositely charged polymers, nanoparticles, or proteins, provides the opportunity for the formation of 5-500 nm thick films with monolayers of various substances growing in a preset sequence on any substrate—preferably silicon or gold—at a growth step of about 1 nm.

Introduction Planar substrate Colloidal substrate Conclusion

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• The polyelectrolytes used were:– PAH (polyallylamine hydrochloride)– PSS (polystyrene sulfonate)– PEI (polyethyleneimine)

• The powders used were:– μm-Al2O3

– nm-Al2O3

– nm-ZrO2

Introduction Planar substrate Colloidal substrate Conclusion

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• Example of LbL assembly on a planar substrate

PSS

PAH

Substrate

PAH

PSS

ZrO2

PEI

ZrO2

PEI

PSS

Al2O3

PSS

Al2O3

PSS

PEI

PSS

PEI

Substrate

Introduction Planar substrate Colloidal substrate Conclusion

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nm-ZrO2

μm-Al2O3 nm-Al2O3

Introduction Planar substrate Colloidal substrate Conclusion

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0

2000

4000

6000

8000

10000

12000

14000

16000

18000

0 5 10 15 20 25 30 35

Cha

nge

in F

requ

ency

(H

z)

Layer

(PEI/PSS)2 + (Al2O3/PEI/PSS)4 + (Al2O3/PSS)11

ConclusionColloidal substratePlanar substrateIntroduction

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0

5000

10000

15000

20000

25000

30000

35000

40000

0 5 10 15 20 25 30 35 40

Cha

nge

in F

requ

ency

(H

z)

Layer

(PEI/PSS)2 + (PEI/ZrO2/PSS)4 + (PEI/ZrO2)11

Introduction Planar substrate Colloidal substrate Conclusion

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Top (nm-Al2O3)

Middle (nm-ZrO2)

Bottom (nm-Al2O3)

ConclusionColloidal substratePlanar substrateIntroduction

(PEI/PSS)2 + (PEI/ZrO2/PSS)4 + (PEI/ZrO2)11 + (PEI/PSS)2 + (Al2O3/PSS)15 + (PEI/PSS)2 + (PEI/ZrO2)15 + (PEI/PSS)2 + (Al2O3/PSS)15

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• Example of LbL assembly on colloidal particles

Adsorption Centrifuge Deionized Water

Centrifuge Adsorption Centrifuge Deionized Water

Sep

arat

ion

Rin

se

Sep

arat

ion

Rin

se

Sep

arat

ion

PS

S

PE

I

1:Colloidal Suspension

2: Expose to PSS-2mg/mL(negative charge)

3: At 14,000

rpm for 5 min

4: Expose to D.I.

H2O

5: At 14,000

rpm for 5 min

6: Expose to PEI - 2mg/mL(positive charge)

7: At 14,000

rpm for 5 min

8: Expose to D.I. H2O

Introduction Planar substrate Colloidal substrate Conclusion

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Latex + (PEI/PSS)2 + (PEI/Silica)

Latex + (PEI/PSS)2 + (PEI/Silica) + (PEI/PSS)2 + (PEI/Silica)

Latex + (PEI/PSS)2 + (PEI/Silica) + (PEI/PSS)2 + (PEI/Silica)

ConclusionColloidal substratePlanar substrateIntroduction

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Introduction Planar substrate Colloidal substrate Conclusion

(Al2O3/PSS) + (PEI/PSS) + (PEI/ZrO2)

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ConclusionColloidal substratePlanar substrateIntroduction

(Al2O3/PSS) + (PEI/PSS) + (PEI/ZrO2)3

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• Planar substrate

– Layer by layer self-assembly determined that, not only were the multilayers successfully deposited, but the morphology can also be controlled.

– Future experiments include optimizing the working pH to provide maximum density in the Al2O3 and ZrO2 layers.

• Colloids– Layer by layer self-assembly determined that

colloidal particles can be assembled from coating m-size particles with nm-size particles.

– Future work will include determining how to better attach the nm-size particles to the m-size particles.

Introduction Planar substrate Colloidal substrate Conclusion