1. Grambling State University Layer by Layer Nanoarchitectures Assembled from Alumina (Al 2 O 3 ) and Zirconia (ZrO 2 ) Systems Kristan R. Moore 1, 2, Tabbetha A. Dobbins 1, 2, and Vimal Kamenini 2 1 Dept. of Physics, Senior, Grambling State University 2 Institute for Micromanufacturing, Louisiana Tech University

2. Grambling State University IntroductionPlanar substrateConclusionColloidal 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

3. Grambling State University 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 pH μm-Al 2 O 3 nm-Al 2 O 3 nm-ZrO 2 ζ (mV) pH ζ (mV) IntroductionPlanar substrateColloidal substrateConclusion

4. Grambling State University 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. IntroductionPlanar substrateColloidal substrateConclusion

5. Grambling State University The polyelectrolytes used were: –PAH (polyallylamine hydrochloride) –PSS (polystyrene sulfonate) –PEI (polyethyleneimine) The powders used were: –μm-Al 2 O 3 –nm-Al 2 O 3 –nm-ZrO 2 IntroductionPlanar substrateColloidal substrateConclusion

6. Grambling State University Example of LbL assembly on a planar substrate PSS PAH Substrate PAH PSS ZrO 2 PEI ZrO 2 PEI PSS Al 2 O 3 PSS Al 2 O 3 PSS PEI PSS PEI Substrate IntroductionPlanar substrateColloidal substrateConclusion

7. Grambling State University nm-ZrO 2 μm-Al 2 O 3 nm-Al 2 O 3 IntroductionPlanar substrateColloidal substrateConclusion

8. Grambling State University Change in Frequency (Hz) Layer (PEI/PSS) 2 + (Al 2 O 3 /PEI/PSS) 4 + (Al 2 O 3 /PSS) 11 ConclusionColloidal substratePlanar substrateIntroduction

9. Grambling State University Change in Frequency (Hz) Layer (PEI/PSS) 2 + (PEI/ZrO 2 /PSS) 4 + (PEI/ZrO 2 ) 11 IntroductionPlanar substrateColloidal substrateConclusion

10. Grambling State University Top (nm-Al 2 O 3 ) Middle (nm-ZrO 2 ) Bottom (nm-Al 2 O 3 ) ConclusionColloidal substratePlanar substrateIntroduction (PEI/PSS) 2 + (PEI/ZrO 2 /PSS) 4 + (PEI/ZrO 2 ) 11 + (PEI/PSS) 2 + (Al 2 O 3 /PSS) 15 + (PEI/PSS) 2 + (PEI/ZrO 2 ) 15 + (PEI/PSS) 2 + (Al 2 O 3 /PSS) 15

11. Grambling State University Example of LbL assembly on colloidal particles AdsorptionCentrifugeDeionized Water CentrifugeAdsorptionCentrifugeDeionized Water Separation Rinse Separation Rinse Separation PSS PEI 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 IntroductionPlanar substrateColloidal substrateConclusion

12. Grambling State University Latex + (PEI/PSS) 2 + (PEI/Silica) Latex + (PEI/PSS) 2 + (PEI/Silica) + (PEI/PSS) 2 + (PEI/Silica) ConclusionColloidal substratePlanar substrateIntroduction

13. Grambling State University IntroductionPlanar substrateColloidal substrateConclusion (Al 2 O 3 /PSS) + (PEI/PSS) + (PEI/ZrO 2 )

14. Grambling State University ConclusionColloidal substratePlanar substrateIntroduction (Al 2 O 3 /PSS) + (PEI/PSS) + (PEI/ZrO 2 ) 3

15. Grambling State University 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 Al 2 O 3 and ZrO 2 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. IntroductionPlanar substrateColloidal substrateConclusion