| NSF Org: |
CHE Division Of Chemistry |
| Recipient: |
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| Initial Amendment Date: | July 9, 2012 |
| Latest Amendment Date: | September 11, 2013 |
| Award Number: | 1213835 |
| Award Instrument: | Continuing Grant |
| Program Manager: |
George Janini
CHE Division Of Chemistry MPS Directorate for Mathematical and Physical Sciences |
| Start Date: | July 15, 2012 |
| End Date: | June 30, 2016 (Estimated) |
| Total Intended Award Amount: | $342,306.00 |
| Total Awarded Amount to Date: | $354,305.00 |
| Funds Obligated to Date: |
FY 2013 = $223,800.00 |
| History of Investigator: |
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| Recipient Sponsored Research Office: |
1608 4TH ST STE 201 BERKELEY CA US 94710-1749 (510)643-3891 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
307 McCone Hall Berkeley CA US 94720-4767 |
| Primary Place of
Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): |
Macromolec/Supramolec/Nano, Geobiology & Low-Temp Geochem, International Research Collab |
| Primary Program Source: |
01001314DB NSF RESEARCH & RELATED ACTIVIT |
| Program Reference Code(s): |
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| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.049 |
ABSTRACT
In this project funded by the Macromolecular, Supramolecular and Nanochemistry Program of the Chemistry Division, Hengzhong Zhang and Jillian Banfield of the University of California at Berkeley will investigate titania nanocrystal growth, structure and morphology evolution, and structural incorporation of impurities under extremely high pressure hydrothermal conditions. The approach is to synthesize titania nanoparticles with and without the presence of dopants, to employ a special diamond anvil cell in performing an in situ synchrotron X-ray diffraction study of nanocrystal growth and structure change in supercritical water at very high temperatures and pressures, to perform ex situ microscopy and X-ray absorption studies on the nanocrystals to determine dopant distributions, and finally to use theoretical modeling methods to understand the physical and chemical properties of titania nanoparticles under such conditions. The broader impacts involve the integration of undergraduate student training and education into the research project, the incorporation of research results into the undergraduate laboratory curriculum, the broad dissemination of research results through publications, presentations and a nanogeoscience website, and the potential impacts of the research in many areas of science.
Nanocrystals are small pieces of material with dimensions on the order of 1 to 100 nanometers, which is about 10,000 times smaller than the width of a human hair, and they are important for a wide range of technologies including pigments, electronics, and medical imaging. The ability to control nanocrystal growth to achieve required specifications such as phase, size, and morphology and defect structure is key to the realization of their use nanotechnologies. Nanocrystal growth under extreme temperature and pressure conditions is largely unexplored, and this project will pursue this research topic using both state-of-the-art experimental techniques and theoretical and computational modeling. Such research will enhance our knowledge about manipulating nanocrystals and potentially lead to the discovery of new nanocrystal structures and compositions.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
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PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
This project resulted in several findings that provide significant understanding of titania nanocrystal growth under hydrothermal conditions and phase transformation under pressure. 1) Conventionally, it is believed that small crystals grow via atomic addition of ions at the expenses of dissolution of smaller particles in a solution. However, under hydrothermal conditions, it was discovered that titania nanoparticles can grow into curved (seemingly strained) nanorods via oriented attachment of smaller particles in order to lower the total system energy. 2) Yttrium doping on titania nanoparticles can induce new phases and amorphization as the pressure increases, which is not present in undoped titania nanoparticles, due to strong modification of the nanoparticle surface structure and energy. This may be used to control nanomaterial stability suitable for desired applications. 3) The driving force for nanocrystal growth via oriented attachment was found to be primarily the interatomic Coulombic interactions between nanoparticles rather than the previously assumed surface energy reduction. The findings from this project not only are important for controlling nanomaterial growth and transformation for some applications, but also provide knowledge for understanding some Earth and planetary events that are hard to explore directly, such as crystal formation and growth in hydrothermal vents in deep oceans of the Earth.
This project provided semester-long and summer research opportunities to undergraduate students. Students learned experimental methods of synthesizing nanoparticles through chemical reactions, growing nanocrystals in both dry and hydrothermal conditions, and experimental techniques in materials characterization using X-ray diffraction, ultraviolet-visible light absorption and thermal gravimetry. More importantly, they developed creative and critical thinking for solving scientific problems.
Last Modified: 08/09/2016
Modified by: Hengzhong Zhang
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