Chemical Engineering Department Seminar

Greg Beaucage
Professor of Chemical and Materials Engineering
University of Cincinnati, Cincinnati, OH 45221-0012

The commercial production of polymers often leads to chain structures with weakly branched chains that dramatically affect the rheology and mechanical properties of these commodity materials.  Macromolecular branching can also be introduced during processing of commercial polymers, leading to changes in polymer properties.  The success or failure of a particular polymer resin often depends on the difference in structure between chains with no branches or chains with one branch in 10,000 monomers.  Most analytic techniques are insensitive to such small changes in chemical structure.  We have developed a new method to quantify such topological features using a scaling model that can be applied to neutron scattering data.  This scaling method has been used to quantify a variety of model and commercial polyethylene and hydrogenated polybutadiene materials.  Moreover, the method has also been applied to a wide range of molecular and nanoscale architectures such as the branched structure of inorganic or biomolecular aggregates, the structure of star and cyclic macromolecules, and as a new tool to understand biomolecular folding processes.  We are currently expanding this approach to the dynamic study of molecular devices based on rotaxane and catenane cyclic molecular architectures.

Beaucage G, Determination of branch fraction and minimum dimension of fractal aggregates Phys. Rev. E 70 031401 (2004).

Kulkarni AS, Beaucage G, Quantification of branching in disordered materials J. Polymer Sci. B-Polymer Phys. 44 1395-1405 (2006).

Kulkarni AS, Beaucage G, Investigating the molecular architecture of hyperbranched polymers using small angle neutron scattering. Macromolecular Rapid Comm. 28, 1312-1316 (2007).

Sztucki M, Narayanan T, Beaucage G, In situ study of aggregation of soot particles in an acetylene flame by small-angle x-ray scattering J. Appl. Phys. 101 114304 (2007).

Ramachandran R, Beaucage G, Kulkarni AS, McFaddin D, Galiatsatos V, Persistence Length of Short-Chain Branched Polyethylene. Macromolecules 41 9802-9806 (2008).

Beaucage, G. Toward Resolution of Ambiguity for the Unfolded State Biophysical Journal 95 503-509 (2008).

Ramachandran R, Beaucage G, Kulkarni AS, McFaddin D, Merrick-Mack J, Galiatsatos V, Branch content of metallocene polyethylene Macromolecules 42 4746-4750 (2009).

Beaucage G., Kulkarni AS, Dimensional Description of Cyclic Macromolecules submitted Macromolecules (2009).

Rai DK, Ramachandran R, Beaucage G Scaling Model for Symmetric Star Polymers Submitted Macromol. Rapid Comm. (2009).

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