Since his arrival to CAMP, Clarkson University has received over $8,500,000 in external funding for research related to metallic particles. A large part of this funding was provided by the US Army for developing advanced materials which can effectively obscure IR radiation. This research has resulted in several novel materials which have met U.S. Army performance targets and are presently scaled up to industrial volumes. Another important focus of Professor Goia's research is the development of precious metals for electrocatalysts, energy conversion and storage applications. In the area of proton exchange membrane fuel cells (PEMFC), he has already received a $540,000 multi-year grant from Umicore/Germany to develop highly dispersed Pt and Pt alloy nanoparticles deposited on various substrates. Professor Goia has also received $350,000 from NYSTAR and NanoDynamics for research involving the development of precious and base metal electrocatalysts for solid oxide fuel cells (SOFC). Several other grants are supporting his research in precious and base metal powders for microelectronics applications, metallic flakes for electromagnetic interference shielding, metallic nanoparticles for medical/biological and printable electronics, and metal composite powders for metallurgical applications. In addition Professor Goia's work in basic research has been recognized by the National Science Foundation, which has given him and his colleagues over $1,400,000 for their work in elucidating the mechanisms of fine particles formation in homogeneous solutions.
Visiting from the University of Jordan (www.ju.edu.jo), Professor Fadwa Odeh spent the summer of 2007 in CAMP Professor Yuzhuo Li’s laboratory investigating the self-assembly behavior of benzotriazole in water. 1H-Benzotriazole (BTA) is the parent of an important class of industrial chemicals due to its excellent anti-corrosion property. BTA is relatively hydrophobic and has limited solubility in water. The aqueous solubility for BTA has been reported to be between 1.8-2.5 weight percent (1.5-2.1 M). In this study, the self-assembly behavior of BTA in aqueous solutions below its solubility limit has been revealed for the first time using various NMR techniques such as chemical shift, spin-lattice relaxation time (T 1), and self-diffusion coefficient (D) measurements and dynamic light scattering (DLS) studies. See Figure 3. The critical aggregation concentration (CAC) is estimated based on these NMR data to be about 16-20 mM. Such a critical aggregation concentration is comparable with the typical critical micelle concentration (CMC) for surfactants that have moderate aqueous solubility. While sharing the same driving force for association, surfactant molecules aggregate into micelles and BTA self-assemble into nanoparticles to avoid the exposure of their hydrophobic moiety. The self-assembly behavior of BTA may not be limited to benzotriazole. It might be generally true for all poorly water soluble species, to aggregate at concentrations below their solubility. Due to the fact that these substances are widely used in many practical applications, it is fundamentally important to understand the nature and extent of such aggregations. For example, many important passivating agents used in CMP applications are poorly soluble in water. The aggregation of these species at low concentrations may have a significant impact on the effective concentration and their surface-availability.
Figure 3. The effect of increasing the concentration of BTA on the chemical shift at 300K.
Figure 4. Scheme for preparing a sphere containing Ag nanoparticles on its surface. The preparation and characterization of uniform poly(styrene-co-glycidyl methacrylate-co-divinyl benzene) submicron spheres has been successfully achieved. Polyethyleneimine (PEI) was attached to the surface of a sphere and subsequently Ag nanoparticles were deposited on the colloidal surface. These submicron polymer spheres can be utilized in metal complexation and nanocomposite formation. The picture, in the square at the right, is a TEM (transmission electron microscope) image of Ag nanoparticles deposited on the surface of a uniform poly(styrene-co-glycidyl methacrylate-co-divinyl benzene) submicron sphere.
PARTICLE TRANSPORT, DEPOSITION AND REMOVAL
Drug Delivery and Lung Deposition
Flows during Corona Discharge
and Experimental Techniques for Human Health and Security in Indoor Environments
Novel Polymer Materials and Polymerization Techniques
Research in Professor Devon Shipp's laboratories centers on novel polymer-based materials, including nanocomposites, hydrogels and biodegradable polymer networks. Projects in Professor Shipp’s laboratory that utilize the group’s expertise in polymer synthesis, in particular living radical polymerizations, include: (a) the production of polymer modified metal oxide particles for potential use in photovoltaic cells, (b) the synthesis and study of biodegradable polymer network structures, (c) the development of methods to make highly uniform and surface-functionalized polymer spheres for use as templates for semi-conductor nanoparticle deposition (Figure 4), and (d) the synthesis of well-defined block copolymers that act as hydrogels and templating materials. More information on Professor Shipp’s research activities can be found at www.clarkson.edu/~shippda.