Research Opportunities for Students
AREA OF RESEARCH: Thermochemical studies of weakly bound adducts
METHODS USED: Solution calorimetry, Isothermal Microcalorimetry, spectroscopy, computer analysis; sometimes molecular mechanics and semiempirical quantum mechanical calculations
MINIMUM EXPERIENCE: two semesters of General Chemistry
PREFERRED EXPERIENCE: Modern Analytical Chemistry, one semester Organic Chemistry
STUDENTS: There are usually two or three students doing research, in the summer and/or during the school year.
Mai Yang and Kelsey Paltzer presented research on dyes and metal mordants
Students from this lab have presented their research at the
Department Seminar; at a Symposium on Undergraduate Research in Math,
Science and Engineering at Argonne National Laboratory; at a meeting of the Northeastern Wisconsin section
of the American Chemical Society;
at the annual UW Oshkosh Celebration of Scholarship; and at the UW System Symposium for Undergraduate Research.
Thermochemistry of dye binding by metal mordants.
People have been dyeing fabrics since prehistoric times. By
trial and error it was discovered
that some metal salts improve the binding of dyes to fabrics, allowing the color to resist fading
in water or sunlight. The binding agents are called mordants, meaning "biting."
Spectroscopic and calorimetric experiments provide qualitative
information about the color change,
and quantitative information about the effects of metals on a dye's binding strength.
J. E. Mihalick, K. M. Donnelly. “Using metals to change the colors of natural dyes.” Journal of Chemical Education 83, 1550-1551 (2006).
J. E. Mihalick, K. M. Donnelly. "Cooking up colors from plants, fabric and metal." Journal of Chemical Education 84, 96A (2007).
|Spring 2007 graduate Amber
Schultz studied metal binding to polysaccharides.
||Spring 2007 graduate Catherine
Polster studied dyes.
||Andrew Loken '09 also studied dyes.|
Thermochemistry of heavy metal binding by polysaccharides.
The cyanobacterium Microcystis flos-aquae, which grows in
produces a polysaccharide capsule that binds heavy metal ions such as cadmium, copper and lead.
In the long run this material may be useful for cleaning sites contaminated by toxic metals.
Thermochemical studies let us determine which metals the
polysaccharide binds most strongly.
Measuring the enthalpy (DeltaH) of a reaction gives us the strength of the bond,
and measuring the equilibrium constant (K) for a reaction tells us the extent of binding.
We looked at the properties of a variety of metal (II) ions as well as the simple sugar units which make up the polysaccharide to understand why the polysaccharide prefers certain metals.
J. E. Mihalick, W. P. Griffiths III*, J. E. Muten*, T. A. Olson*, J.
B. Hein*, "Thermochemistry of Binding of Lead (II) and Cadmium (II) by
Saccharides in Aqueous Solution." Journal of Solution Chemistry
28, 1025-1036 (1999).
D. L. Parker, J. E. Mihalick, J. L. Plude, M. J. Plude,T. P. Clark*, L. Egan, J. J. Flom*, L.C. Rai, H.D. Kumar, "Sorption of metals by extracellular polymers from the cyanobacterium Microcystis aeruginosa f. flos-aquae strain C3-40." Journal of Applied Phycology 12, 219-224 (2000).