NSF NANOPARTICLE SYNTHESIS AND PROCESSING

Nanoparticles, including nano-clusters, -layers, -tubes, and self-assembled systems, are seen as precursors of nanostructured materials and devices with tailored properties. An initiative called "Ultrafine Particle Engineering" for new concepts and fundamental research on methods to generate nanoparticles at high rates started in 1991 in NSF's Engineering Directorate in collaboration with the Directorate for Mathematical and Physical Sciences. The work has included contributions on fundamental physics and chemistry for generation of nanoparticles with engineered properties via aerosols, colloids, plasma, combustion, sol-gel, chemical vapor deposition, molecular and cluster assembling, and other synthesis methods. Emphasis has been placed on awards to small groups for multidisciplinary projects with a focus on fundamental research. The Ultrafine Particle Engineering initiative originated in NSF's Chemical and Transport Systems Division in the particulate and multiphase processes area; it was developed in collaboration with various disciplinary programs such as "Ceramics, Metals, and Electronic Materials," "Physical Chemistry," and "Combustion and Plasmas"; and it has covered a variety of theoretical, process, and instrumentation aspects. NSF's support was approximately $6 million/year in the last five years. Two review conferences were held in collaboration with NIST: the NSF-NIST conferences on Ultrafine Particle Engineering (1994, proceedings edited by M.C. Roco, R. Shull, and D.T. Shaw) and on Nanoparticles (1997, proceedings edited by D.T. Shaw, M.C. Roco, and R. Shull; both proceedings published by SUNY Buffalo and NSF).

Ultrafine particle engineering involves the synthesis and processing of nanometer-sized particles with controlled properties for applications in advanced materials such as ceramics, metals, optical structures, and semiconductors. Metals and ceramics produced by consolidating nanoparticles with controlled microstructures have been shown to exhibit properties substantially different from materials with coarse microstructures. New properties include greater hardness, higher yield strength, and ductility in ceramic materials. The band gap of nanometer-scale semiconductor structures increases as the size of the microstructure decreases, raising expectations for many possible optical and photonic applications. Novel applications have been proposed: laser ablation of materials to generate nanoparticles used in nanoelectronics; production of polymer semiconductor composites to develop nonlinear optics for waveguides; molecular and nanostructure self-assembly techniques for integrated circuits and chemical sensors; high performance catalysts; control of nanoparticles resulting from combustion and plasma processes; hypersonic plasma expansion for nanostructured coatings; and special sensors applied in chemical plants and the environment. Future work aims to expand research on nanoparticle processing into nanostructured materials and devices, advanced simulation techniques at mesoscale, and novel instrumentation. NSF will emphasize support of scientific discoveries in generation of nanoparticles with controlled characteristics, research on particle processing into microstructured blocks with engineered properties, introduction of new principles of operation for devices, and development of new modeling and experimental tools.

GOAL: SYNTHESIS & PROCESSING OF NANOPARTICLES

NICHE: PRODUCTION AT HIGH RATES; SPECIAL PROPERTIES

RELEVANCE: ENGINEERED MICROSTRUCTURED MATERIALS

EACH PROJECT HAS 3 CO-P.I.s FROM DIFFERENT DISCIPLINES

• Examples

  • Nanoparticle Formation Using a Plasma Expansion Process, U. MN
  • Nanocrystalline Materials Prepared by Spark Erosion, UCSB
  • Controlled Production of Nanoparticles Using Microemulsions, MIT
  • Combustion Process for Nanosized Reinforced Composites, U. WA-SL
  • High Volume Production Using Laser Ablation of Microparticles, UT
  • Particle-particle and Particle-substrate Interactions, Purdue U.

• Others

  • Submicron Aerosol Agglomeration, UCLA
  • Nanophase Composite Materials for Magnetic Refrigeration, SUNY-B
  • Effect of Electric Fields in Nanoparticle Flame Reactors, U. Cincinnati