215 Jahn Lab
1 Forestry Dr.
Syracuse, New York 13210
Ph.D., 1974, SUNY College of Environmental Science and Forestry; Arthritis Foundation Fellow, Purdue University, West Lafayette, IN, 1973-1977; Assistant Professor, 1977; Associate Professor, 1983-1987, Polytechnic University, Brooklyn, NY (now part of New York University); Visiting Scientist, CERMAV-CNRS, Grenoble, France, 1984-1985, 1990, 1995; AFRC-Norwich, UK, 1989; Visiting Professor, University Joseph Fourier, Grenoble, France, 1987-1995, Visiting scientist- Xerox Research Centre of Canada, 1985,1986. Cellulose and Renewable Materials Division (CELL) of the American Chemical Society- Treasurer 1990-1992; Awards Chair 2005-2008. He is also an associate of the ACS Committee on Chemical Nomenclature. Dr. Winter serves on grant review panels for NSF, NIH, and EPA, is a frequent reviewer of grant applications and original research submissions to numerous journals, and a participant in National Academy of Science topical workshops.
William Winter is interested in the molecular architecture of polymer molecules, particularly polysaccharides, and its relation biological function and end-use applications. Typically, his students work with x-ray diffraction, electron microscopy, solution and solid-state NMR, and the use of computers/ networks to explore chemical and biochemical problems. Structural chemists try to understand the interplay of static and dynamic structure with physical properties or biological functions. Current research is in the following areas:
Microfibrils in plant cell walls are aggregates of cellulose nanofibers. Similarly, exoskeletons of Arthropods such as shrimp, crabs, lobsters, and krill contain significant amounts of chitin nanofibers. It had been show that such fibers can convey outstanding improvements in mechanical properties to plastics if the nanoparticles can be well dispersed in the plastic matrix. We are actively involved creating new ways to alter the surface chemistry of such nano-particles so that we can control the quality of the dispersion. We are also interested in many other aspects of cellulose nano-science including the use of these needle-like particles as templates for the production of ceramic particles. Finally we are looking at the synthetic preparation of porous spheres of cellulose using what is described as ‘nanoprecipitation’. Such particles are expected to be useful in diverse controlled release applications.
Within the cell walls of higher plants about 50% of the mass is cellulose, a linear, ribbon-like, high molecular-mass polymer of the simple sugar, glucose. Currently, there is considerable interest in utilizing cellulose and the other cell wall components as alternative, sustainable carbon sources for the production of both fuels and products. In order to break down these molecules by enzymatic methods, the enzymes, which are fairly large molecules themselves, have to make close contact with specific regions of individual molecules so that they can catalyze the cleavage of the chain. This problem is sometimes referred to as ‘recalcitrance’. In our lab we are seeking to understand the interactions between plant cell wall components, i.e., cellulose, hemicelluloses, lignin, etc. One approach is to use a type of nuclear magnetic resonance spectroscopy called High Resolution Magic-Angle Spinning NMR or HRMAS-NMR to observe the spectra of intact, never dried plant cells. Since the cells contain many molecules, these spectra are complex. One way to simplify them is to look at the differences in spectra between from wild type cells and analogous cells obtained from a similar tissue obtained from a plant with a single gene suppressed or overexpressed and grown under identical conditions. The differences in the spectra relate to the expressed molecular differences that derive from the alteration of that single gene. We can use this method to identify compositional differences and, through NOESY NMR, identify the interactions that stabilize and strengthen the mechanical properties of the plant cell wall and provide the basis for what is often called ‘recalcitrance’.(Barnhart, 2011)
Cellulose is the most abundant organic compound on earth. It is a linear polymer of several thousand glucose units linked in a regular manner. In the form of cotton and paper it has been used for centuries as a material for textiles, paper and construction materials. Processing of cellulose often requires the ability to either dissolve it or swell it so that large molecules like enzymes can reach the surface and the interior of cellulose particles. Additionally, the formation of cellulose into continuous fibers or films requires dissolving cellulose. In our lab of the use of N-methylmorpholine-N-oxide as a route to the preparation of films from mixed polysaccharide blends containing cellulose. It was recognized that such blends could find applications in controlling the porosity of cellulose membranes, if the blended polymer was water soluble.(Luo, 1994) More recently, we are working with ionic liquids such as tetra-butylammonium fluoride (TBAF) dissolved in dimethyl sulfoxide as well as various imidazolium chloride salts. Such systems dissolve cellulose and most other polysaccharides up to molar masses of ~200,000 and are of interest both for the possibility of new, economic routes to rayon as well as for their use in polysaccharide reaction chemistry and characterization.(Cheng, 2010)
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