Dr. Franklin M. Chen
Hydrophobically Modified Polyelectrolytes
I have been fascinated with the ability of a protein molecule to fold into an exact 3-dimensional shape to exhibit its enzymatic or cellular functional properties. One of the major driving forces of this folding is so-called the hydrophobic forces that water-hating amino acid residues in the protein molecule to move away from the water environment. I propose to study this fascinating folding phenomena using a synthetic chemistry approach. In the polymerization reactor, I can design a protein-like synthetic polymer by varying the ratio of the hydrophobic and the hydrophilic monomers and synthesize a polymer that consists of hydrophobic residues of known size and shape. Using x-ray scattering or other analytical techniques, one can study the polymer size and shape of these polymers. The outcomes of this research would provide insights to the fundamental folding phenomena.
Sonochemistry for Environment
Acoustic cavitation,arisen from high sound intensity, causes bubble collapses that produces transient intense localized hot spots of high temperature (~5000 oC) and very short lifetimes (10-6 seconds). High intensity ultrasound has been shown to enhance catalysis activity of nickel powder an order of 100,000 fold. This project studies the ultrasound-driven chemical reactions of hydrocarbons in the presence of inorganic or organic materials. One specific aspect of the proposed research is to oxidize organic contaminants in aqueous solutions with or without photo-catalysis with the acoustic cavitation. Photo-catalysis of hydrocarbons with titanium oxide sol is expected to be noticeably improved with high intensity ultrasound. The ultimate goal of this project is to apply sonochemistry to solve various environmental issues concerning the Green Bay and Great Lakes watershed.
Mesoporous and Microporous Materials
A mesoporous structure is a regular, long-range array of pores whose size ranges from a few nanometers to tens of nanometers. Structures with pore size smaller than a few nanometers are usually called microporous. These structures contain an enormous amount of surface area relative to their volume and have found many applications in optical filter and fuel storage. Mesoporopus structures can be made using a sol-gel process. Block copolymers are generally used as templates for the structures. Block copolymer molecules in aqueous solutions consist of two parts: a hydrophilic portion and a hydrophobic portion. When block copolymers are mixed with ceramic forming reagents, reactions are proceeded such that ordered arrangement of organic spheres are surrounded by a polymerized silicate matrix. After the composite is formed, the organic component is removed by solvent extraction or thermal decomposition. This project uses hydrophobically modified polyelectrolytes as templates for making mesoporous structures. These structures will be evaluated for toxic vapor removal and fuel storage purposes.
Quantum Chemistry of Colors:
The origin and the manifestation of colors are revealing in learning, teaching and sources for creating new knowledge. I have used color for cyanine dyes both in the general education class (Chemistry of Materials, Chem283C) and in my quantum class (Structure of Matter, Chem321). For beginners, color chemistry provides specific links between real-world phenomenon and quantum chemistry. For upper-level students, colors provide students appreciation of the sophistication various quantum chemistry models such as particle-in-a-box, and Huckel theory. Hyperchem modeling software will provide initial platform for innovation. Eventually, I will use natural bond orbital approach to reveal colors originated from charge-transfer reactions. In one of the UW-faculty development seminars in 2006 at UW-Washington County, I had opportunity to listen to Prof. Frank Weinhold seminar on valency and bonding. During the seminar, I witnessed the power and the beauty of natural bond orbital donor-acceptor approaches to chemistry problems. Interactions between occupied donor orbital and an unoccupied acceptor orbital will provide energy stabilization which is often referred to as a ‘two-electron stabilizing interaction. Scholarship activity in this field will insure that the undergraduate experiences in quantum projects feed directly into advanced academic and industrial applications.
Fingerprint Lifting, Preservation and Development:
The concerns over the terrorism have motivated me to develop projects that will be useful for government and public citizens in deterring terrorism. One specific project out of this concern is a forensic research focusing specifically to fingerprint lifting. Fingerprint collections and identifications are used by the law reinforcement offices in the court. On normal surfaces, fingerprints were photographed with a digital camera and different lens types to get the photos to be as close to 1:1 as possible. Enhanced contrast can be achieved by applying chemicals to the fingerprints. The enhanced fingerprints were then lifted using an adhesive tape. The fingerprints on the tape were then computer scan at a high resolution of 500-1000 ppi (pixels per inch). When the surfaces are not normal such as when vehicles (to which suspects left fingerprints) are covered in road salt, neither the fingerprints enhancement process nor the fingerprint lifting process can achieve its intended goals. On winter days, such difficulty could impart substantial costs to the law reinforcement officers and to taxpayers in collecting convincing evidences for criminal justice.I have been approached by an officer in the police department of Green Bay to develop methods and chemicals to enhance contrast of the fingerprints and preserve the fingerprints when vehicle surfaces (to which suspects left fingerprints) are covered in ice, road salts and dirt. I will be working both organic-based and inorganic-based sol-gel chemistries to tackle this problem. Scholarship in this field could support national research efforts to deter global terrorism.