The ultimate goal of this exploratory project is the design, synthesis and functional characterization of a new class of nanostructured materials ? block copolymer supramolecular assemblies. The major aspects to be addressed in this study are: i) donor-acceptor interactions in supramolecular assemblies; ii) distribution of the components in the assemblies and at the interfaces; iii) the effect of nanoscopic confinement of electroluminescent additives on their optoelectronic properties; iv) the benefits and limitations of electroluminescent supramolecular assemblies for OLEDs, solar cells, and other energy harvesting and conversion applications. This project will include cooperative efforts in (a) synthesis of efficient electroluminescent additives and (b) characterization of donor-acceptor assemblies aiming (c) development and optimization of novel materials for efficient energy conversion and energy harvesting. Upon completion of this research project, the fundamental knowledge of the sequence molecular structure - mesoscale organization - optoelectronic properties - of this new material will be gained. This knowledge will be applied toward a range of important applications of the donor-acceptor block copolymer assemblies in the emerging fields of renewable energy harvesting and efficient energy conversion.

NON-TECHNICAL SUMMARY

This project is directed towards the rational design of novel class of nanostructured polymeric materials. These materials can open a venue to technical innovations in flexible electronics, large area displays, efficient plastic solar cells, energy conservation. Therefore, highly efficient technologies based on this approach are extremely beneficial to society as they aid to conserve natural resources. The project stipulates strong collaboration with scientists at the National Institute of Standards. The educational component is closely tied to research objectives. The students of both undergraduate and graduate levels will be involved in the project, thus gaining experience and knowledge of the modern instrumentation and techniques in diverse areas of materials science, chemistry, and nanotechnology in an intellectually stimulating research environment.

Project Report

Block copolymer supramolecular assemblies (SMA) is a new class of metamaterials with unique properties. A traditional SMA consists of a block copolymer and a low-molecular weight additive selectively attached to one of the blocks via relatively weak hydrogen bonds. When deposited in a form of thin films, SMA reveal periodic structures, either fingerprint-like or hexagonally ordered dots with the domain size in the range of 5 to 50 nanometers (Figure 1). It makes SMAs potentially valuable for many industrial applications spanning from electronics and solar power harvesting to bioengineering. In the frame of the NSF project we have designed a series of SMAs based on non-hydrogen interactions (non-HB SMA). It allows us significantly broaden the variety of the additives. In particular, we have demonstrated that functional additives may be incorporated into the structure of SMA thus providing precursors for further chemical transformations. A novel additive bisEDOT designed by the co-PI J. D. Tovar (Johns Hopkins University) specifically for this project is suitable for the non-HB SMA formation. Being a precursor for a semiconducting polymer, bisEDOT is a very promising additive to form functional SMA. For the first time we have demonstrated that an additive can be polymerized directly in the SMA and measured electrical characteristics of semiconducting nanodots organized in arrays of 30 nm periodicity. Some of the results are published in the paper by Hagaman, D.; Enright, T. P.; Sidorenko, A. Block Copolymer Supramolecular Assembly beyond Hydrogen Bonding. Macromolecules (2012), 45(1), 275-282. Another paper is submitted for publication in Polymer Chemistry, RSC: Block Copolymer Supramolecular Assembly using a Precursor to a Novel Conjugated Polymer. Three presentations at the ACS meetings and one at the MRS meeting were given. Two graduate students (one from USciences, Sidorenko’s group, another from UJH, Tovar’s group) working on this project have successfully defended their M.S. thesis. Besides the intellectual and technological contribution, our work has broader impact. Three graduate students and three undergrads were directly involved in this research. They gained important skills in several modern techniques and instrumentation used in different fields of chemistry and materials sciences, i.e. atomic force microscopy, spectroscopic ellipsometry, different thin film deposition technique, special organic synthetic approaches, etc. Even more importantly, the students were exposed to the atmosphere of academic research and discovery. Two of the students involved in the research are African American, and three of them are females – the groups that are underrepresented in STEM. The results of our project were incorporated in two graduate courses developed by A. Sidorenko: Introduction to Polymer Science and Physics and Chemistry of Surfaces and Interfaces. Also, we used the Philadelphia Science Festival in 2011 as a forum to showcase our work to the broad audience. In June of 2011, 2011, A. Sidorenko represented USciences hosting 25 summer campers (ages 3-9) and their chaperones from Zhang Sah, a local nonprofit organization. In March of 2012, 6 high school students from South Philadelphia High School and University City High School entered Sidorenko’s lab to run a series of scientific experiments. The results were presented at the USciences Research Day and at the 43rd MARM meeting of the ACS.

Agency
National Science Foundation (NSF)
Institute
Division of Materials Research (DMR)
Application #
0947897
Program Officer
Andrew J. Lovinger
Project Start
Project End
Budget Start
2009-09-01
Budget End
2012-08-31
Support Year
Fiscal Year
2009
Total Cost
$296,000
Indirect Cost
Name
University of the Sciences in Philadelphia
Department
Type
DUNS #
City
Philadelphia
State
PA
Country
United States
Zip Code
19104