Drexel University Open Nanoscale Materials Characterization Facility

Published on October 6, 2006 at 12:56 AM

At the nanometer scale, composition and characterization of materials leads to new discoveries for researchers around the world. To springboard this research, Drexel University will officially open its doors to a new state-of-the-art facility available to worldwide researchers on October 25, 2006. Workshops on the research conducted in the facility and its equipment will showcase Drexel’s new research hub to Philadelphians.

The Materials Characterization Facility (MCF) is part of the A.J. Drexel Nanotechnology Institute, located in the new Edmund D. Bossone Research Enterprise Center (Market Street between 31st and 32nd Street). With its unique instruments and expert staff the MCF already attracts researchers not only from regional universities but also from a growing number of companies and national labs including Arkema Inc., BAE Systems, Global Protection, Greene Tweed Inc., Headwaters Technology Innovation Group, iCeutica, Kulicke and Soffa, and Nanoblox.

Representative Equipment and Resources
• Drexel’s Raman spectrometers offer one of the largest arrays of excitation wavelengths, from UV to infrared, in the nation and the largest on the East Coast. Two Renishaw RM1000 Raman Spectrometers are available in the facility. The Raman Effect is used to identify and characterize the chemical bonding and structure of materials on the nanoscale in a non-contacting, non-destructive manner. Through laser light excitation, the RM1000 allows rapid spectrum acquisition times and sub-micrometer spatial resolution. The RM1000 also maps out the phase composition, phase transformations and stresses in a variety of materials. Recent applications include the analysis of nanoporous materials, nano-composites, nanofibers and nanotubes, nanoparticles, and nanostructured polymer systems.

• The FEI XL30 Environmental Scanning Electron Microscope (ESEM) with wet mode capability and TSL EBSD/OIM and EDAX EDS attachment offers users a highly precise image analysis in a variety of studies such as cell culture scaffolding adhesion, high temperature ceramic characterization, drug delivery micro-sphere characterization, and water condensation inside nanotubes.

• The Zeiss Supra 50VP Scanning Electron Microscope with Oxford EDS and WDS attachments for elemental analysis is the newest addition to the characterization tools in the MCF. It is capable of delivering high-quality images at the scale of a few nanometers and can map the elemental composition of advanced nanostructured materials.

• The MTS Nano-Indenter XP provides the most advanced technology available to acquire fast, accurate mechanical data on a variety of surfaces at the submicron scale. Characterizing surfaces down to the level of a few nanometers has become increasingly important to a wide range of manufacturers and researchers. Nanoindentation allows researchers to determine the elasticity and hardness of materials. Nano-indentation tests measure hardness by indenting the materials using very small indentation forces and measuring the depth of the indention that was made. Applications include measurement of the mechanical properties of “hard” (metals, ceramics, semiconductors) and “soft” materials (hydrogels, living tissue, biopolymers).

• The Digilab Excalibur-3000 Infrared Microspectrometer is an instrument that complements the chemical analysis from the Raman spectrometers by supplying information on the absorbance properties of materials. It can determine the spatial distribution and characteristics of active ingredients, inactive materials, and coatings in pharmaceutical tablets. It can be used to study polymer laminates frequently used in packaging to get good combinations of flexibility and durability. It can also be used in studies of biopolymers.

The instruments in the MCF are available on a pay per hour basis, seven days a week. Difficult and extraordinary characterization problems can be resolved with the help of Dr. Zhorro Nikolov, MCF director, and Dee Breger, director of microscopy, whose work has been featured in various nationwide publications.

Examples of Research/Applications
It was with the help of these technologies that the director of the Drexel Nanotechnology Institute, Dr. Yury Gogotsi, and a research team were able to develop new materials for supercapacitors in hybrid cars, laptops and other devices. They found that the capacitance of supercapacitors increased when the size of pores in the carbon electrode material decreased below 1 nm across. Gadgets like those listed above, in addition to their batteries, contain capacitors that provide quick bursts of energy. Capacitors can not store as much power as batteries, but the latest supercapacitors have begun to narrow the gap. This work can lead to smaller, lighter, more powerful supercapacitor devices, according to Gogotsi.

Graduate students use the MCF labs to test their groundbreaking ideas for new materials and to study the properties of existing properties on the nanoscale. Doctoral student Aaron Sakulich uses the Zeiss Scanning Electron Microscope to study the composition of new concrete he is attempting to create from natural materials.

Doctoral student Sandip Basu uses the nanoindenter to analyze the deformation mechanisms in various crystal structures. He and Dr. Michel Barsoum developed a procedure for generating indentation stress-strain plots from spherical tip nanoindentation experiments. He and Gogotsi’s group also use the nanoindenter in combination with Raman spectroscopy to study formation of new metastable phases of silicon during indentation. Master’s student Melanie Patel uses Raman mapping and Infrared spectroscopy to analyze the changes in bone composition due to aging and mechanical stresses. This research conducted under the guidance of Drs. Surya Kalidindi and Haviva Goldman is aimed at bringing new understanding of bone compositional changes at the nanostructure level.

The Natural Polymers and Photonics Group of Dr. Caroline Schauer uses the resources of the MCF to study polymer materials found in nature. These natural polymers include chitosan, which is derived from crustacea shells and alginate, which is obtained from the cell walls of brown algae. Doctoral students Matthew Cathell and Jessica Schiffman process these natural materials into nanoscale thin films and fibers for a variety of applications, including heavy metal sensors and artificial skin grafts. For their characterization they use a variety of MCF instruments, particularly Infrared and Raman spectroscopy, and SEM microscopy, to monitor chemical and physical changes in their miniscule nano-constructions.

The Consortium
Philadelphia researchers can join the Materials and Nanotechnology Consortium, which was created to enhance the unique relationship with the corporate community Drexel University has enjoyed since its founding in 1891. The Consortium’s objectives are to identify, promote and engage in strategic research and education in advanced materials, nanotechnology, biotechnology and bio-nanotechnology. These initiatives meet the needs of industry, government and students through interdisciplinary collaborations, partnerships, dedicated expertise, access to leading-edge materials characterization facilities, and innovative educational programs.

Eight organizations have joined the Consortium thus far. Membership starts at the bronze level for $5,000 and reaches the platinum level at $50,000. Membership offers priority access to MCF equipment at reduced rates. It also allows access to biannual on-campus seminars on research and development, one-on-one advising from Drexel faculty in specified areas of research, access to students, Web presence and identity. Non-member individuals and organ

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