Introduction/Why Do We Care? • Nanoparticles have been around for millennia, being produced by various natural phenomena. However, since the industrial revolution, the number of nanoparticles in the environment has been increasing steadily. Titanium dioxide nanoparticles are present in many consumer products, such as: • Cosmetics • Paper • Medications • Sunscreens • Questions will arise, such as is there a buildup of nanoparticles in the food chain, and what affect, if any, do TiO2 nanoparticles have on any form of life? • These questions are important because: • Nanoparticles have a tremendous potential for the future of our society • Overall, the potential environmental and health ramifications are still relatively unknown. By: Anthony Timson, Nhien Le, and Werner Roth Faculty Sponsors: Dr. Alexandre Yokochi and Dr. Jeff Nason 10-2 m TiO2 is commonly used in medications such as Zyrtec-D. 10-3 m 10-4 m Pure TiO2 nanocrystal Al2O3 + TiO2 doped nanocrystal 10-5 m Synthesis of Doped Titanium Dioxide Nanoparticles 10-6 m Hair ~100 µm 1 mm 10-7 m 100 µm 10-8 m Proposed mechanism to dope TiO2 with aluminum in order to trace the origin of nanoparticles in the environment: 10 µm 10-9 m 1 µm O2 10-10 m Nanoparticles in solution. 100 nm Ti Putting Things in Perspective Results/Findings Al 10 nm 1.0 nm • For thermal evaporation the size distribution from SEM images ranged from 110-230 nm. • Due to the color and behavior of the nanoparticulates this method was replaced with a centrifugal wash and freeze drying process. • Freeze drying process corrected the color issues by eliminating the EG residue. • Rough size estimation from XRD place particle size around 100 nm. • XRD showed particles as crystalline structures. 0.1 nm • Low Temperature, • Catalyst Free Method Project Goals Ant (~2 mm) DNA (~2 nm) • Synthesize traceable doped nanoparticles with similar surface chemistry to pure rutile phase TiO2 nanoparticles • Develop a method to control dopant concentration • Develop a method to control particle size predictably while minimizing size dispersion • Step 1: Create the Precursor Solution • Precursor: Tetra-n-butyl titanate (TnBT) and aluminum tri-sec-butoxide (AtsBT) is dissolved in ethylene glycol (EG). • Step 2: React the Solution: • add the precursor to a solution of with a ratio of 1 mL EG to 1 mL of 20.0 nm of agitated water. • Step 3: Centrifugal washFinalsolution washed with Step 4 (a): Thermal Evaporation: Heat to remove water and butyl alcohol keep agitated (~6 hr), then heat in vacuum oven to remove EG (~6 hr) Step 4 (b): Freeze Dry Nanoparticles post thermal evaporation from Sample 1. Nanoparticles post freeze dry treatment for Sample 7. Our size regime Target size Red Blood Cells (~10 µm) Chuang, H.Y., & Chen, D.H. (2008). Catalyst-free low temperature synthesis of discrete anatase titanium dioxide nanocrystals with highly thermal stability and UVC-cut capability . Journal of Nanoparticle Research. 10, 233-241. Li, Y., Lim, S.H, and White, T. (2004). Controlled Synthesis and Characterization of TiO2 Nanoparticles via a Sol-Gel Method. International Journal of Nanoscience. Vol 3, No. 6, 749-755. Gutsch, A., Kramer, M. Michael, G., Muhlenweg, H., Pridohl, M., and Zimmermann, G. (2002). Gas-Phase Production of Nanoparticles. KONA Power and Particle Journal. No. 20, 24-37. Croll, S.G., Taylor, C.A. (2007). Hydrated Alumina Surface Treatment on a Titanium Dioxide Pigment: Changes at Acidic and Basic pH. Journal of Colloid and Interface Science. 314, 531-539. XRD image of Sample 7, approximately 100 nm. Acknowledgements: The team would like to thank Dr. Philip Harding, Dr. Alexandre Yokochi, and Dr. Jeff Nason for providing guidance and funding for the project. We would also like to thank Robert Kimmell and Kevin Caple, two graduate students at OSU, for assisting in analysis of the samples. Notice the color difference between Sample 1 (left) and Sample 7 (right). Sample 1 was thermal treated, and Sample 7 was freeze dried. SEM imaging of nanoclusters from Sample 1.