3) synthesis and chemical manipulation of high aspect ratio nanosized metallic flakes and needles/wires as possible IR obscurants; and 4) preparation and evaluation of both oil-in-water microemulsion and surface functionalized carrier particles such as silica and oligochitosan for in vivo binding to and removal of several problematic therapeutics and illicit molecules that are commonly overdosed. The binding concepts at a molecular level have now been proven using AFM measurements with the help of Professor Sokolov at Clarkson, thus corroborating in vitro chromatographic evidence that the subject toxins are removed from blood. Also the chemical principle of pi-pi complexation between two different types of aromatic rings, as measured by NMR, has recently been shown to apply to binding the tyrosine molecules that circumvent the binding site of ricin. This may provide clues as to how to prevent the deadly bioactivity of this toxin. Their work also includes the 5) synthesis of new generations of phosphor-containing composite particles for use in improving lighting efficiency and 6) investigation of new vinyl monomers for synthesis of photoactive polyelectrolytes having potential for use in expandable polymer composites. The concept is being applied to surface functionalization of silica filler particles already used in commercial dental resins.
Professor Partch’s expertise has been appreciated by academic, government and industrial audiences during a 3-week trip to present in Singapore, Hong Kong and Seoul and Pohang, Korea in December, 2004. In addition, his short course “Surface Modification Technologies To Enhance Industrial Performance of Powdered Materials” set an attendance record of 26 registrants at the Particles 2005 Meeting in San Francisco in August, 2005.
U.S. Army Research Project: Smart Responsive Nanocomposites for Soldier Protection
A recently awarded $2M Army Research Office (ARO) project on Smart Responsive and Nanocomposite Systems has just started. The research is led by CAMP Director Professor Babu and CAMP Professors Minko and Sokolov. The whole team includes eleven other CAMP Professors: Ahmadi, Cetinkaya, Li, Jha, Fendler, McLaughlin, Moosbrugger, Morrison, Privman, Shipp, and Suni.
One team, led by Professor Minko, is developing smart responsive materials for use as protective fabrics and sensors. The research focuses on synthesis and assembly of responsive nanostructured thin polymer-nanoparticle films that are able to switch properties (wetting, permeability, volume, shape) upon exposure to external stimuli. This behavior will be used to regulate protective properties of textiles. The same principle will be explored for the development of bio/chemical sensors. The responsive composite films will detect environmental changes and transform the change of the film properties into optical/electrical signals.
Professors McLaughlin, Ahmadi, and Minko are developing models for protective clothing againstchemical and biological attacks. They are preparing models for motions of fluids and droplets on surfaces with variable wetting angles. The goal is to allow for transport of transpiration, but to protect the solids from outside contaminants.
Self Healing Materials
Another team, led by Professor Sokolov, is developing self-healing materials. Structural polymers, though attractive from mechanical and chemical points of view, are susceptible to deterioration due to the formation and propagation of cracks. This leads to degradation of their mechanical properties and decreases life time. The purpose of the present research is the development of special healing capsules embedded in the polymer matrix. When a crack propagates, it ruptures the capsules. Healing “glue” leaks out into the crack, seals, and “cures” the crack. This repairs the crack, and to some extent recovers the mechanical integrity of the polymer. See Figure 3.
Professors Ahmadi, McLaughlin, and Sokolov are examining the details of the mechanisms by which cracks are healed, in self healing materials. They are developing models for flows in micro-cracks and the subsequent curing process for this Army funded project. The goal is to provide a fundamental understanding of the processes involved so that the self healing materials can be optimally designed.
Figure 3. This figure shows a dent in a self-healing polymer. Bright spots indicate the presence of the healing glue “simulator, ” a fluorescent dye encapsulated inside a capsule. When a dent is formed, it breaks the capsules, and the “glue” is released. This can be seen in the picture as a bright area covering the dent.
Micro- and Macro-Mechanical Modeling of Self Healing Composite Materials
Professors Jha, Cetinkaya and Ahmadi are studying the mechanical properties of self healing materials for this Army funded project. The objectives are to provide a fundamental knowledge of the mechanical behavior of undamaged and healed materials. A multi-scale model will be used to predict the effects of “healing fiber” concentration, aspect ratio, and modulus on the mechanical properties of the composite material. The response of self-healing composite structures to quasi-static and dynamic loads will be investigated. The modeling will determine stress/strain concentrations, failure mechanisms, stress wave propagation, and healing efficiency.
Electrochemical Deposition of Metals for Semiconductor/ Nanotechnology Applications
Electrochemical methods provide inexpensive and powerful tools to deposit nanostructures and to tailor the nanostructure of surfaces. CAMP Professor Ian Suni is using electrochemical deposition and dissolution of metals to form controlled nanostructures for applications to semiconductor processing, catalysis, and biosensor development. For example, his laboratory has developed electrochemical methods for planarizing both Cu interconnect and Ta diffusion barrier materials on Si devices. Professor Suni is also involved in fundamental research supported by the U.S. Army and the National Science Foundation to develop new electrochemical biosensors .
Quantum Physics for Nanotechnology and Information Processing
CAMP Professor Vladimir Privman, of Clarkson University's Departments of Chemistry, Electrical and Computer Engineering, and Physics, is the Director of the NSF-funded Center for Quantum Device Technology. He is exploring implications of quantum physics for future nanotechnology and information processing. He has also contributed to theories of uniform fine particle synthesis. Professor Privman's main contributions have been in developing and evaluating approaches to utilize semiconductor heterostructures and quantum wells, based on the silicon-chip device technology, for quantum information processing (quantum computing) and spintronics. He has also worked in modeling electron transport of relevance to single-quantum measurement and control.
Modeling of Next-Generation Semiconductor Devices
Professor Ming-Cheng Cheng in collaboration with Professor Privman is currently studying spin-polarized transport and injection in compound semiconductor spintronic devices. The goal of this project is to develop transport models at different levels of efficiency and accuracy for modeling and optimization of semiconductor spintronic devices.