| NSF Org: |
CHE Division Of Chemistry |
| Recipient: |
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| Initial Amendment Date: | July 10, 2014 |
| Latest Amendment Date: | July 10, 2014 |
| Award Number: | 1410581 |
| Award Instrument: | Standard Grant |
| Program Manager: |
George Janini
CHE Division Of Chemistry MPS Directorate for Mathematical and Physical Sciences |
| Start Date: | July 15, 2014 |
| End Date: | June 30, 2018 (Estimated) |
| Total Intended Award Amount: | $300,000.00 |
| Total Awarded Amount to Date: | $300,000.00 |
| Funds Obligated to Date: |
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| History of Investigator: |
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| Recipient Sponsored Research Office: |
438 WHITNEY RD EXTENSION UNIT 1133 STORRS CT US 06269-9018 (860)486-3622 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
97 North Eageville Rd Storrs CT US 06269-3136 |
| 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 |
| Primary Program Source: |
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| 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
Many technological applications of nanoparticles rely on our ability to control the interactions of nanoparticles to exploit their ordered structures and collective properties. In this project funded by the Macromolecular, Supramolecular and Nanochemistry Program of the Chemistry Division, Prof. Yao Lin and his students at University of Connecticut are conducting studies to understand the physical mechanisms that make possible the controlled assembly in solution of nanoparticles with different types of molecules (ligands) grafted onto them, and to predict where the tendencies to aggregate further and to disperse are balanced so that equilibrium is reached. A goal is a general approach for prediction and control of the formation of bigger "supramolecular" structures from a large set of nanoparticles. Understanding the mechanism of the assembly process can contribute to the generation of hierarchical, multicomponent materials and systems, eventually approaching the level of sophistication found in nature. Using biologically inspired mechanisms to synthesize supramolecular structures provides new opportunities and challenges in chemical research and education. The PI aims to address students needs for interdisciplinary education and high quality research experience in this emerging field. The proposed research will be integrated into curriculum materials and outreach activities, providing interdisciplinary training and vibrant research experiences for students at different levels.
Intermolecular interactions define the self-assembly pathways and the kinetics of the formation of large-scale supramolecular structures. In nature, numerous globular proteins can be "polymerized" into specific helical or tubular assemblies via a well-defined nucleation-growth mechanism, as exemplified by the formation of actin filaments and microtubules. Inspired by the sophisticated assembly mechanism, the PI is developing a general strategy for controlled assembly of ligand-grafted, charged nanoparticles. Guided by a thermodynamic analysis, fibrous supramolecular structures assembled from polypeptide-grafted, charged nanoparticles have been successfully created in the preliminary study. Using these nanoparticles as a model system, the research focuses on: (1) conducting kinetic analysis to understand the nucleation mechanism involved in the fibrous supramolecular assembly of charged nanoparticles, and (2) determining the phase diagram for the self-association of charged nanoparticles and elucidating the transition mechanism between different supramolecular structures. By mimicking nature's assembly approaches, the research is developing a general strategy for assembling nanoparticle building blocks to predictable superstructures, and providing insights into the critical nucleation process that connects kinetic and equilibrium behaviors of nanoparticles self-associations. Particularly, the understanding of thermodynamic and kinetic processes involved in the fibrous assembly of nanoparticles tests the applicability of classic theories obtained from the studies of the protein polymerizations, leading to the need for development of a more generalized model.
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.
Many technology applications of nanoparticles reply on our ability to control the interactions of nanoparticles to exploit their ordered structures and collective properties. In nature, numerous protein subunits such as actins and tubulins can be “polymerized” into specific helical or tubular assemblies via a well-defined nucleation-growth mechanism. Incorporating the nucleation-controlled, cooperative mechanism into the supramolecular assembly process of synthetic subunits can contribute to the generation of hierarchical, multicomponent materials and systems, eventually approaching the level of sophistication found in nature. Using polypeptide-grafted ionic subunits as a model system, this research project focused on understanding the role of nucleation mechanism in the bio-inspired supramolecular assembly of charged nanoparticles in solution, and to determine the possible transition mechanisms between different supramolecular structures. Supported by this grant, the PI’s lab has (1) demonstrated the use of thermodynamic analysis to elucidate the delicate role of the electrostatic interactions between the charged subunits in the nucleation-controlled assembly process; (2) established both the analytic and numerical models that can describe the early and full kinetic processes involving nucleation-growth mechanism; and (3) examined the applicability of the model on the assembly of charged subunits with regulation process and complex pathways. In addition, we have shown that the nucleation-growth kinetic models can be adapted to describe the covalent systems with two-stage polymerization process, for development of auto-accelerated polymerizations with predictable kinetic behavior and molecular weight. Sophisticated kinetic models and methodologies have now been established for the complex system with multiple and competing pathways.
This grant supported three graduate students in their Ph.D. research, and provided the opportunity to train four undergraduate students in the lab. The PI has given 18 invited talks and seminars to present the research achievement made possible by this grant and disseminated the knowledge. The PI has developed and taught an interdisciplinary course on Macromolecular, Supramolecular and Nano-Chemistry, with integrated lecture and lab sections in 2017 and 2018. Two graduate students supported by this grant designed and taught the lab section of the course. By partnering with John Hopkins Center for Talented Youth (CTY), the PI organized the STEM workshop of “Chemical Approaches to Nanomaterials” at UConn on March 12, 2016. 90+ middle/high school students and their parents attended the one-day workshop to learn about fundamental concepts in nanochemistry through a combination of lectures and hands-on activities. Another workshop has been scheduled in March, 2019. The PI organized the first “Research at the interface between chemistry and biology” symposium at UConn, which was support by the Office of Vice President for Research and open to all members at UConn and science teachers at Storrs. The PI has led an effort to establish collaborations with Fudan and Shanghai Jiaotong Universities in China, in the areas of Chemistry and Polymer Science. Through the exchange program, 25+ undergraduate students from the three schools gained the research experience abroad.
Last Modified: 09/28/2018
Modified by: Yao Lin
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