Jeffrey Pyun

Honors

• IBM Faculty Award, 2007
• Office of Naval Research Young Investigator Award, 2007
• NSF CAREER Award, 2006
• NSF USA-JAPAN Nanohybrid Participant, 2003
• Student Award for Outstanding Graduate Research, 2002
• Alfred P. Sloan Research Fellowship, 2009

Education and Appointments

• B.A. 1997, Northwestern University
  
• Ph.D. 2002, Carnegie Mellon University
  
• Postdoctoral Fellow 2002-2004, IBM Almaden Research Center / UC Berkeley
  

Research Interests

• Organic
  
• Materials Synthesis and Characterization
  
• Polymers
  
• Surface Science
  
• Synthesis and Synthetic Methodology
  

Research Summary

Our research program is focused on the synthesis and characterization of novel polymeric and composite materials, with an emphasis on the control of nanoscale structure. Recent developments in polymer and colloid chemistry offer the synthetic chemist a wide range of tools to prepare well-defined, highly functional building blocks. We seek to synthesize complex materials from a "bottom up" approach via the organization of molecules, polymers and nanoparticles into ordered assemblies.

Control of structure on the molecular, nano- and macroscopic regimes offers the possibility of designing specific properties into materials that are otherwise inaccessible. We are particularly interested in compatabilizing interfaces between organic and inorganic matter as a route to combine the advantageous properties of both components. This research is highly interdisciplinary bridging the areas of physics, engineering and materials science with creative synthetic chemistry.

Magnetic Mesoscopic Polymers: Field Induced Assembly of Functional Nanoparticles

We are pursuing a modular synthesis of nanocomposite chains composed of ferromagnetic colloids and functional block copolymers. Controlled and living polymerizations allow the organic chemist to prepare of a wide range of functional block copolymers which will be used as polymeric surfactants in the formation of magnetic colloidal dispersions. In the presence of a magnetic field, these core-shell magnetic nanoparticles align into polymeric chains. The assembled chain can then be locked in by crosslinking of reactive groups attached to the block copolymer surfactant. It is anticipated that the hybridization of these components on the nanoscale will synergistically combine the beneficial film forming properties of organic polymers with the magnetic character of the inorganic colloid. We have developed new synthetic methods using polymeric surfactants to prepare well-defined ferromagnetic nanoparticles and demonstrated that dispersed colloids can be magnetically assembled into mesoscopic 1-D nanoparticle chains, which we refer to as mesoscopic polymer chains, or “meso-polymers.” Functionalization and controlled assembly of these novel building blocks are currently being pursued.

Funding: National Science Foundation, Office of Naval Research, American Chemical Society-Petroleum Research Fund

Collaborators: Tomek Kowalewski (Carnegie Mellon University), Alamgir Karim, Jack Douglas (NIST), Inbo Shim (Kookmin University, Seoul, Korea), Jeanne Pemberton (U of A), Daniel Savin (University of Vermont)

TEM of ferromagnetic polystyrene coated cobalt nanoparticles

Hybrid Nanocomposites for Solar Cells: Conjugated Polymers and Semiconductor Nanoparticles

In collaboration with Neal Armstrong at the U of A, we are investigating the preparation of novel hybrid nanocomposites of CdSe quantum dots with polythiophenes. We are developing novel ligand chemistry to functionalize CdSe quantum dots that will enable electro-copolymerization with thiophene monomers to prepare covalently linked, electroactive materials. In particular, we are investigating the direct modification of transparent conductive oxide materials via electro-polymerization to prepare electrochemically “wired” thin films of polymer-semiconductor hybrids with anodic electrodes. These materials are being investigated for applications as photovoltaic devices and photocatalytic systems for hydrogen generation. This interdisciplinary project combines synthetic organic chemistry, polymers, optical spectroscopy, thin film/surface characterization and device fabrication thru collaboration with a number of research groups at the U of A.

Funding: Department of Energy-Basic Energy Sciences

Collaborators: Neal Armstrong, Zhiping Zheng, Dominic McGrath, Scott Saavedra, Hank Hall, Oliver Monti (U of A)

Magnetic Nanocomposite Thin Films for Magnetic Tape

We are investigating the preparation of nanostructured thin films of organic polymers and magnetic nanoparticles as novel binder materials for magnetic tape. This technology is critical for long term archival storage, which is still the most reliable and cost-effective media for this application. New synthetic methods to functionalize and protect high moment and coercivity ferromagnetic nanoparticles against corrosion and sintering are being developed using organic polymers and polymeric precursors. This project is also highly collaborative with industrial researchers thru the Information Storage Industry Consortium (INSIC), which include, IBM, HP, SONY and Imation.

Funding: INSIC

Collaborators: Ric Bradshaw, Delia Milliron, Spike Nayaran (IBM), Dave Nikles (University of Alabama)

Selected Publications

• “Fabrication of Long CdS Nanowires by Using a Chemical Solution Process,” Shim, I.; Choi, D.-H.; Kim, C.-S.; Pyun, J.; Bowles, S.E. J. Korean Phys. Soc. 2008, 52 ,332-336.

• "Synthesis and Self-Assembly of Polymer Coated Ferromagnetic Nanoparticles," Keng, P.; Shim, I.; Korth, B.D.; Douglas, J.F.; Pyun, J. ACS Nano 2007, 1 ,279-292.

• "Polythiophene-Semiconductor Nanoparticle Composite Thin Films Tethered to Indium Tin Oxide Substrates via Electropolymerization," Shallcross, R.C.; D’Ambruoso, G.D.; Hall, H.K.; Zheng, Z.; Pyun, J.; Armstrong, N. R. J. Am. Chem. Soc. 2007, 129, 11310-11311.

• "Magnetic Assembly and Pyrolysis of Functional Ferromagnetic Nanoparticles into 1-D Carbon Nanostructures," Bowles, S.E.; Wu, W.; Kowalewski, T.; Shalnat, M.; Davis, R.; Pemberton, J.E.; Shim. I.; Korth, B.D.; Pyun, J. J. Am. Chem. Soc. 2007, 129, 8694-8695.

• "Synthesis, Assembly and Functionalization of Polymer Coated Ferromagnetic Nanoparticles," Korth, B.D.; Keng, P.; Shim. I.; Tang, C.; Kowalewski, T.; Pyun, J. ACS Symposium Series, “Nanoparticles: Synthesis, Stabilization, Passivation and Functionalization” 2007, in press.

• "Self-Assembly of Polymer Coated Ferromagnetic Nanoparticles into Mesoscopic Polymer Chains and Visualization using Fossilized Liquid Assembly," Benkoski, J.J, Bowles, S.E.; Jones, R.A.; Douglas, J.F.; Pyun, J.; Karim, A. J. Poly. Sci., Part B, Polym. Phys. 2007, in press.

• "Nanocomposite Materials from Functional Polymers and Magnetic Nanoparticles," Pyun, J. Polym. Rev. 2007, 47, 231-263.

• "Field induced formation of mesoscopic polymer chains from functional ferromagnetic nanoparticles," Benkoski, J.J, Bowles, S.E.; Korth, Bryan, D.; Jones, R.A.; Douglas, J.F.; Karim, A.; Pyun, J. J. Am. Chem. Soc. 2007, 129, 6291-6297.

• "Polymer Encapsulated Metallic and Semiconductor Nanoparticles: Multifunctional Materials with Novel Optical, Electronic and Magnetic Properties," Pyun, J.; Emrick, T.S. Macromolecular Engineering: From Precise Macromolecular Synthesis to Macroscopic Materials, Properties and Applications, Ed. K. Matyjasewski, L. Liebler, Y. Gnanuo, Wiley-VCH, New York, 2007, vol. 4, Ch. 11

• "Polymer Coated Ferromagnetic Colloids from Well-Defined Polymeric Surfactants and Assembly into Nanoparticle Chains," Korth, B.D.; Keng, P.; Shim, I.; Bowles, S.; Nebesny, K.; Tang, C.; Kowalewski, T.; Pyun, J. J. Am. Chem. Soc. 2006, 128, 6562.

• "Synthesis and Direct Visualization of Block Copolymers Composed of Different Macromolecules Architectures," Pyun, J.; Tang, C.T.; Kowalewski, T.; Fréchet, J. M. J.; Hawker, C.J. Macromolecules 2005, 38, (7), 2674-2685.

• "A Structurally Diverse and Highly Efficient Approach to Dendritic Libraries using Click Chemistry," Nugent, A.; Hawker, C.J.; Scheel, A.; Voit, B.; Pyun, J.; Fréchet, J.M.J.; Feldman, A.K.; Yu, P.; Finn, M.G.; Fokin, V.; Sharpless, K.B. Angew. Chemie. Int. Ed. 2004, 43, 3928-3932.

• "Synthesis of Organic-Inorganic Hybrid Nanoparticles: Kinetics of Surface-Initiated Atom Transfer Radical Polymerization and Morphology of Ultrathin Films," Pyun, J.; Jia, S.; Kowalewski, T.; Matyjaszewski, K. Macromolecules 2003, 36, 5094.

• "Synthesis of Well-Defined Block Copolymers Tethered to Polysilsesquioxane Nanoparticles and Their Nanoscale Morphology on Surfaces," Pyun, J. ; Matyjaszewski, K.; Kowalewski, T.; Savin, D.; Patterson, G.; Kickelbick, G.; Huesing, N. J. Am. Chem. Soc. 2001, 123, 9445.

• "Synthesis of Nanocomposite Organic/Inorganic Hybrid Materials Using Controlled 'Living' Radical Polymerization," Pyun, J.; Matyjaszewski, K. Chem. Mater. 2001, 13, 3436.