Hsu Research Group Current Research
Exploration of global properties associated with many polymer processes through elucidation of polymer microstructure. We are interested in four main fields -- polymer phase separation, polymer physical aging, Green processing conditions, and constraint at interfaces - with research focuses on polymers such as polyurethanes, polyethylene, and biodegradable poly(lactic acid) as well as many novel systems. Vibrational spectroscopy, both infrared and Raman, is our primary method of characterization; others important to the group are x-ray, calorimetry, X-ray photoelectron spectroscopy, surface tension, mass spectrometry, atomic force microscopy, and electron microscopy. These experimental techniques are carried out in conjunction with theoretical modeling studies. Our graduates have gone on to academic institutions, government agencies, and industrial laboratories such as Virginia Polytechnic University, NIST, Dow, and Molecular Simulations Inc.
Polymer Phase Behavior of polymers is treated by considering molecular architecture in reacting formulations (AFM image above).
Optical Response of Helical Polymers in a Constrained Geometry. To uderstand film stability , we have designed a unique Langmuir trough (below) to characterize polymer structure and morphology during film formation.
Green Processing - in a collaboration between chemists, we are improving the efficiency of an environmentally friendly radiation curing process, thus enhancing this technique for coating industries. Stress measured in thin film (above)
Reactive blends
Our research deals with the fundamental aspects of multi-component systems. The specific interactions and molecular architecture controlling the phase behavior are examined both experimentally and by simulation techniques. Applications in this area have been applied to the development of high performance composites, coatings, and adhesives. Representative publications include the following:
J. Mat. Sci. 37, 4881 (2002)
We are also interested in the development of interconnected systems. This subject includes a broad spectrum of physical states. Transformation of the disordered state of polymers (molten, solution, or even amorphous chains) into crystalline, gel, and chemically crosslinked systems are studied.
We are also interested in the structure and properties of polymers at surfaces and interfaces. Special reflectance spectroscopic techniques have been designed to characterize ultra thin films. Structures of polymers in such restricted geometries are quite different from the bulk state. The dynamics of the system are also quite different in that structural transformation occurs at such restricted geometries that may not occur in the bulk.
J. Am. Chem. Soc. 124, 8290 (2002)
Recently, our main researches, in collaboration with chemists, emphasize the development of environmentally appropriate materials. We have improved the efficiency of a curing process that does not yield any organic volatile compounds. Working with a number of industrial partners, we are developing alternative feedstocks to petroleum based polymers. Polyesters synthesized from non-food crops have demonstrated great promise. We are also seeking route to reduce the utility of toxic compounds in various materials that are necessary in our daily lives.
