VFP - Visiting Faculty Program (formerly FaST)
May 28 - August 2, 2013
The Visiting Faculty Program (VFP), formerly called Faculty and Student Teams (FaST), seeks to increase the research competitiveness of faculty members and their students at institutions historically underrepresented in the research community in order to expand the workforce vital to the Department of Energy (DOE) mission areas. As part of the program, selected university/college faculty members collaborate with DOE laboratory research staff on a research project of mutual interest. Faculty member participants may invite up to two students (one of which may be a graduate student) to participate in the research project.
Ames Lab provides hands-on research opportunities in materials science.
Javier Vela: Optically active semiconductor-based nanomaterials
Semiconductor nanocrystals exhibit broad absorption spectra and narrow, tunable emission energies between the ultraviolet and the near-infrared range. This makes these materials ideal for use in solar cells, photocatalysis, lighting, and biological imaging. However, current synthesis techniques make it difficult to take advantage of these properties.
This project focuses on the synthetic challenges associated with semiconductor based, heterostructured materials. Students will devise bottom-up synthetic strategies to embed optically active semiconductor and metal nanocrystals in a porous polymer or silica matrix.
Interns will use optical, structural, and computational analysis to model these materials. With this information, students will study the effect of structure and composition on the optical and catalytic properties of the prepared nanocomposites.
Surya Mallapragada: Magnetic Nanocrystals
Potential applications of ferromagnetic nanoparticles range from drug delivery systems to high-density memory devices. However, current commercial synthesis techniques produce magnet clusters with less than ideal crystalline and magnetic properties. One solution is to use magnetotactic bacteria as inspiration. Right now researchers are working to develop efficient lab processes to manufacture magnetic nanocrystals using mineralization proteins from magnetotactic bacteria.
Students will work with a graduate student to mimic and characterize the naturally occurring magnetite nanoparticles found in the bacteria through meticulous hierarchical synthesis. Interns will design and build novel synthetic block copolymers as well as protein polymers produced by recombinant DNA techniques. Synthesis will involve the use of organic templates coupled with mineralized proteins to direct the bio-mineralization and facilitate a bottom-up approach to nanocomposite materials design. Students will uses electron microscopy and magnetic properties measurements to characterize these novel materials.
Tanya Prozorov: Magnetic Nanoparticles
Magnetic nanoparticles with narrow size distribution, large magnetic moment and controlled magnetic anisotropy have important technological applications in a wide variety of areas, ranging from high density data storage and ferrofluidic devices, to quantum computing and targeted drug delivery. Contrary to common beliefs, the smallest nanoparticles are not necessarily the best, as their magnetic moment is often too small and magnetic anisotropy is too weak to be suitable for practical use (e.g., be manipulated by an external magnetic field at room temperature). For many applications, an ideal nanostructured magnetic material can be described as uniformly sized, with maximal magnetic moment per particle and controllable magnetic anisotropy. The particles must have well-defined, preferably elongated, shape, exhibit good crystallinity, belong to one of the highly magnetic compounds, such as magnetite or cobalt ferrite, and be just below the superparamagnetic limit to remain in a monodomain state at the operation temperature.
Using a variety of methods ranging from biomolecule-templated synthesis to controlled atmosphere spray pyrolysis of organomecallic precursors, the team will synthesize uniform 100-150 nm magnetic nanocrystals. Use of low-temperature synthetic approaches permitscontrol over size, shape, and orientation of the magnetic nanostructured crystals. Obtained nanocrystals will be characterized via several analytical techniques, including transmission electron microscopy, magnetization measurements, magneto-optical imaging, and X-ray photoelectron spectroscopy. Uniform magnetic nanocrystals will be functionalized to allow precise surface immobilization of linker molecules. The team will design and fabricate a microfluidic device that will allow continuous separation of superparamagnetic magnetite nanocrystals from a bulk solution containing a heterogeneous population of contaminants. Using magnetic field flow fractionation in a microfluidic device will enable high efficiency separation of specific targeting molecules. Design and proof of concept of the constructed device will be followed by optimization of the flow conditions and magnetic field strength.
For more information, contact Steve Karsjen, (515) 294-5643, karsjen@ameslab.gov, or go to http://science.energy.gov/wdts/vfp/ to register.
