1. Synthesis of Barium Titanate Nanoclusters Presented by Marc Landeweer Advisor: Prof. Slamovich

2. Objectives Examine mechanism of barium titanate synthesis Create barium titanate nanoclusters –Hydrothermal –Distributed Arc Cluster Source (DACS)

3. Hydrothermal Synthesis BaCl 2 or Ba(OH) 2 and TiO 2 precursors Alkaline solution (NaOH) Ar Purge  Reduce xCO 3 Oven heating for 40+ hrs Water wash & centrifuge Dry powder Analyze

4. DACS Titania BaTiO 3 Synthesis Forms TiO 2 nanoclusters TiO 2 nanoclusters added to barium solution, then heated Titania added directly to alkaline barium solution

5. Analysis Methods X-Ray Diffraction Re-sample particle size analyzer (Coulter 250) Carbonate Examination –Acid Test (HCl 10%wt) –Optical Microscopy 200X-500X Transmission Electron Microscopy (TEM) 10,000X-350000X Electron Diffraction Pattern (using TEM)

6. Identifies –Crystal structure –Compound (if crystalline) Detects impurities (~5% limit) Can be used to estimate particle size Requires minimally 0.5 grams of sample X-Ray Diffraction

7. TEM/Electron Diffraction High Magnification ImagingHigh Magnification Imaging –Determine size & morphology Drawbacks:Drawbacks: –Requires delicate sample preparation –Very sensitive to contamination Electron diffraction patternElectron diffraction pattern –Identifies crystalline or amorphous –Used to identify sample and crystal information

8. Particle Size Analyzer Uses laser diffraction of suspension Limited to about 40nm Does not give much information alone –No indication of sample composition –Little morphological data –Requires properly dispersed sample

9. Control Group 060502-01,-02,-03 & 2H –0.4M Ba; 1.0M NaOH; 1.1:1 Ba:Ti; 40+ hours –Relatively high purity –XRD appears normal for all samples 2H shows shift in lattice parameter Concentrate analysis of 060502-02 –XRD –TEM –Particle Size Analyzer –Acid Test (control)

10. 060502-02 XRD

11. Particle Size Analysis

12. TEM Wide Particle Size Distribution Follows laser diffraction distribution Crystalline Smallest range ~70nm 12,000X

13. 150,000X

14. 100,000X Note the large difference in particle size

15. Group 062502: Ba Concentration Adjusted barium concentration –062502-01 = 0.16M –062502-02 = 0.08M –062502-03 = 0.04M High Purity Samples Examined under XRD, Laser Dispersion, TEM

16. XRD Low Carbonate Sharp Peaks

17. Particle Size Analysis

18. TEM 062502-01 Still have wide particle size distribution 12,000X

19. TEM 062502-01 40,000X

20. TEM 062502-02 100,000X 30,000X Very Wide Size Distribution Smallest Particles Larger Comparable to 062502-01

21. TEM 062502-03

22. General Patterns from 062502 Decreased [Ba] yields larger particles –Higher concentration provides more nuclei for barium titanate formation Results are consistant with proposed dissolution-precipitation mechanism Future Approaches: –Adjust Ba Molarity without changing mass

23. DACS Titania Under TEM Amorphous Component 300,000X

24. DACS Synthesis I: DACS Titania added to BaCl 2 & NaOH [Ba]~0.1M –Phosphine Surfactant II DACS Titania with BaOH 2 [Ba]~0.1M –Phosphine Surfactant III DACS Titania with BaOH 2 [Ba]~0.1M –Sodium Citrate Surfactant IV DACS Titania mixed with BaCl 2 & NaOH [Ba]~0.4M –No Surfactant All Samples yielded too little product for proper XRD or particle size evaluation

25. DACS Syn I Grey precipitate formed soon after addition to BaCl 2 & NaOH solution Grey powder suspected to be barium carbonate Washed with DI water and dried to form powder Prepared sample for Coulter Machine –Sample data insufficient to produce result Performed acid test on DACS Syn I & 060502-02 to compare reaction with dilute hydrochloric acid –Inspected results under optical microscope Examined DACS Syn I under TEM

26. DACS Syn II & III Processed with Barium Hydroxide –Formed barium carbonate precipitate too quickly –Used filter to remove precipitate DACS Syn II – Used 06/21 Titania –Bis(p-sulfonatophenyl) phenyl phosphine dihydrate dipotassim salt DACS Syn III – Used 0718 Titania –Using Sodium Citrate Dihyrate Na3C6H5O7 * 2 H2O Washed with HCl & Water Samples not examined under TEM

27. DACS Syn IV Processed directly using DACS Formation of white precipitate very soon after DACS reaction No Surfactant Ba Concentration ~0.4M (compared to NaOH)

28. DACS Syn IV TEM Quite abnormal High Cabonate

29. DACS Syn IV TEM take two

30. Final Conclusions Final? Far from…. Precipitation-Dissolution Dominates Present Literature –Project results can be interrupted to fit either model Nanoparticle synthesis in only water proves to be very difficult to process –Brownies in motion? Brownian motion? –Present processing method does not account for Brownian motion (e.g. water or acid wash)

31. Nanoparticle Synthesis Solvothermal: Chen & Jiao –Barium alkoxide (H 4 Ba 6 (O)-(OCH 2 Ch 2 OCH 3 ) & Ti(OC 4 H 9 -n) 4 Using organic precursors or organic films: Lee, Yao, Imai, & Aksay –Titanyl acylate and barium acetate, fine but not nano –Yielded Nanoparticles with barium titanium methoxypropanoxide (BaTi(OCH 2 CH(CH 3 )OCH 3 ) 6 on alkoxide-Kraton thin film

32. Future Work Standard Hydrothermal: –Determine affect of increasing Ba concentration not changing BaCl 2 mass –Develop method of powder collection accounting for Brownian motion For DACS: –Retry direct reaction of DACS, post washing with alcohol –Adjust Ba:Ti to as close to 1:1 as possible –Perform entire reaction and post-reaction in nitrogen atmosphere