| NSF Org: |
DMR Division Of Materials Research |
| Recipient: |
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| Initial Amendment Date: | June 19, 2019 |
| Latest Amendment Date: | June 19, 2019 |
| Award Number: | 1904525 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Andrew Lovinger
alovinge@nsf.gov (703)292-4933 DMR Division Of Materials Research MPS Directorate for Mathematical and Physical Sciences |
| Start Date: | July 1, 2019 |
| End Date: | June 30, 2022 (Estimated) |
| Total Intended Award Amount: | $183,824.00 |
| Total Awarded Amount to Date: | $183,824.00 |
| Funds Obligated to Date: |
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| History of Investigator: |
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| Recipient Sponsored Research Office: |
101 COMMONWEALTH AVE AMHERST MA US 01003-9252 (413)545-0698 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
120 Governors Drive Amherst MA US 01003-9263 |
| 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): | POLYMERS |
| 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
PART 1: NON-TECHNICAL SUMMARY
This collaborative project brings together scientists at the University of Massachusetts Amherst and the University of Pennsylvania to gain new understanding of how mechanical properties, like stiffness and strength, change when a polymeric material is made into a film with thickness near the size of an individual molecule. Ultra-thin films, such as the ones studied in this project, are desired to help decrease energy consumption in processes like filtration, as well as in semiconductor manufacturing. However, current materials are unable to provide sufficient strength in these applications. New experimental methods will be combined with molecular simulations to understand how structures in the polymer thin films affect their properties in these highly confined states. Beyond the broad impact related to the development of new fundamental science and materials-design guidelines that will decrease materials waste and increase energy efficiency, this project will provide new opportunities for educating Ph.D. students, undergraduate students, and high-school students through rich, collaborative research experiences involving both experiments and simulations.
PART 2: TECHNICAL SUMMARY
This collaborative project will provide new fundamental data and knowledge on the role of block copolymer domain structure in controlling the full mechanical response of ultra-thin polymer films, where film thickness is comparable to or smaller than the domain structure size scale. The proposed approach unites the strengths of advanced simulations and novel experimental methods to test new hypotheses based on the role of position within a confined material on segmental mobility and inter-chain entanglements, and the consequential impact on mechanical properties. Experimentally, a recent mechanical measurement method, called The Uniaxial Tensile Tester for Ultra-Thin films (TUTTUT), will be used to quantify the mechanics of ultra-thin block copolymer films. The experiments will integrate with simulations that use coarse-grained models to predict the molecular response of polymer films, and the simulations will provide a local picture of the changes in the entanglement network and local dynamics as a function of position away from the interfaces in the block copolymer films. Through these efforts, the co-PIs will support the education, training, and inspiration of the next generation of materials scientists and engineers, with a focus toward increased participation of women and traditionally under-represented minorities.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
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.
Thin polymer films are key to numerous current and future technologies, ranging from protective coatings to membranes and filters. The use of thinner films is desirable for increasing efficiency and minimizing energy consumption; however, the use of ultra-thin films is limited by their low mechanical strength.
Intellectual Merit: Our research has used recently developed experimental measurement methods for thin film mechanical properties to understand the influence of structure on the properties of block copolymer films. We studied block copolymers composed of polystyrene and poly(2-vinyl pyridine). We took advantage of our ability to study thin films in order to process these materials using a solvent vapor annealing method. This process allows us to have films with two different structures, one referred to as cylindrical and one referred to as lamellar, with identical chemical compositions. From these measurements, we determined that the cylindrical structured films have a higher failure strength compared to the lamellar structured films. We associated this difference with the change in molecular entanglements within the two different structures. In addition to these measurements, we also discovered that the mechanical properties of the block copolymer materials changed significantly when in contact with water. In particular, the strain to failure, or the amount that the material can be stretched before failing, increased more than 17 times as compared to films not in contact with water. This finding is significant due to the small amount of water that was determined to infiltrate the block copolymer film and the large increase in material toughness. This finding suggests new methods, which are environmentally-friendly, to enhance polymer film mechanical performance.
Broader Impacts: The advances from this research provide new insight for materials scientists and chemists who are designing polymers that will be stronger in ultra-thin film applications. In particular, the water-based toughness enhancing mechanism may be beneficial in the design of thinner membranes used in water filtration. In addition, the principal investigator and students involved in this research have led significant outreach efforts to share their experience in polymer science and engineering to inspire K-12 students to pursue future careers in STEM. In particular, we have hosted elementary school students for laboratory tours, and the principle investigator gave a nationally-broadcasted webinar to K-12 educators on bioinspired materials science examples that can help to enhance their science and engineering lessons.
Last Modified: 10/29/2022
Modified by: Alfred J Crosby
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