| NSF Org: |
CBET Division of Chemical, Bioengineering, Environmental, and Transport Systems |
| Recipient: |
|
| Initial Amendment Date: | May 21, 2014 |
| Latest Amendment Date: | May 21, 2014 |
| Award Number: | 1403049 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Nora Savage
nosavage@nsf.gov (703)292-7949 CBET Division of Chemical, Bioengineering, Environmental, and Transport Systems ENG Directorate for Engineering |
| Start Date: | September 1, 2014 |
| End Date: | August 31, 2017 (Estimated) |
| Total Intended Award Amount: | $195,000.00 |
| Total Awarded Amount to Date: | $195,000.00 |
| Funds Obligated to Date: |
|
| History of Investigator: |
|
| Recipient Sponsored Research Office: |
615 W 131ST ST NEW YORK NY US 10027-7922 (212)854-6851 |
| Sponsor Congressional District: |
|
| Primary Place of Performance: |
500 W 120th Street, 801 Mudd New York NY US 10027-6902 |
| Primary Place of
Performance Congressional District: |
|
| Unique Entity Identifier (UEI): |
|
| Parent UEI: |
|
| NSF Program(s): | INTERFAC PROCESSES & THERMODYN |
| Primary Program Source: |
|
| Program Reference Code(s): |
|
| Program Element Code(s): |
|
| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.041 |
ABSTRACT
PI: Kumar, Sanat / Panagiotopoulos, Athanassios
Proposal Number: 1403049 / 1402166
Institution: Columbia University / Princeton University
Title: Collaborative Research: Exploiting Void Symmetries to Control the Self-Assembly of Nanoparticles
The assembly of nanoparticles (NPs) into colloidal crystals is a promising way to obtain ordered nanocomposite materials with unique properties determined by the choice of the constituent NPs. If successful, this novel approach will have a significant impact on the ability of experimentalists to rationally design ordered colloidal crystals for a wide range of optical and catalytic applications, such as photonic crystals, optical switches and filters, and catalytic devices. The PIs have shown a novel way to selectively stabilize one crystal structure over another possible one by the use of polymers that can intercalate between the NPS.
Essentially, the PIs have made an interesting discovery that, even when the energy, pressure, and packing fraction for two isomorphs, e.g., HCP and FCC, are the same, the distribution of voids within the crystals are different. By filling the voids with polymers of different length, they were able to show that one can selectively stabilize HCP over FCC crystals. Based on these findings, they propose to make use of this novel insight about void symmetries and size-distributions to select a desired polymorph from a suite of competing crystal structure. In this proposal, they propose to investigate what design principles are needed to achieve their goal.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
Note:
When clicking on a Digital Object Identifier (DOI) number, you will be taken to an external
site maintained by the publisher. Some full text articles may not yet be available without a
charge during the embargo (administrative interval).
Some links on this page may take you to non-federal websites. Their policies may differ from
this site.
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.
Intellectual Merit: The novelty of the work we proposed was to critically exploit the void size distributions in colloidal crystals by using polymer chains of appropriate architecture and length to achieve two long-outstanding goals in soft matter engineering:
(i) Crystal Structures: We stabilizes a desired crystal morphology from a suite of competing structures which have very similar free energies (e.g., face centered cubic versus body centered cubic; diamond versus tetrastack hard sphere morphologies), by using the fact that the polymer entropy is maximized strongly in one of morphologies. We predicted the design criteria, in terms of polymer chain length, topology, energetics and stiffness, and how they can be tailored to selectively stabilize any one of these competing morphologies.
(ii) Liquid-liquid coexistence: For systems at lower overall densities, the crystal phase is destabilized. Here we use the fact that long chains lose entropy when they are entrapped in a crystal to destabilize it in favor of self-assembled nanoparticle structures (such as fractal aggregates) and also well-dispersed systems. These ideas do not apply in the case of short chains, where we find that the crystal is likely only unstable relative to the dilute phase.
Broader Impacts: The key idea underlying our proposed work was a simple concept void size distributions in colloid crystals play a central role in determining the thermodynamics of polymer/nanoparticle mixtures. To our knowledge, no other group has proposed to exploit this fact to tune the liquid, self-assembled and solid phase structures, and hence properties, of the resulting nanoparticle-based materials. These transformative research activities were coupled to extensive education and outreach activities. Driven by our recent success in recruiting high school and undergraduate students for summer research, and with well-developed interactions with Florida A&M University (an HBCU), we continued to recruit underrepresented students (both women and minorities) at both the undergraduate and graduate levels. Several of these students have gone on to STEM careers emphasizing the success of this pipelining approach.
Last Modified: 09/01/2017
Modified by: Sanat K Kumar
Please report errors in award information by writing to: awardsearch@nsf.gov.
