Home	Faculty	Research	Graduate Program	Undergraduate Program	Courses	Brookhaven

		Benjamin S. Hsiao Professor B.S., 1980, National Taiwan University; Ph.D., 1987, University of Connecticut; Postdoctoral Fellow, University of Massachusetts, 1987-1989; Scientist, DuPont Company, 1987-1997; Adjunct Associate Professor, University of Delaware, 1994-1997; Spokesperson, X27C (Advanced Polymers Beamline) and X3A2 Beamlines, National Synchrotron Light Source, Brookhaven National Laboratory 1997-; Guest Professor, Changchun Institute of Applied Chemistry, Chinese Academic of Sciences, 2000-; Editorial Advisory Board, Journal of Macromolecular Science- Physics, 1995, Journal of Polymer Research, 1995, High Performance Polymers, 1996; Chinese Journal and Applied Chemistry; Polymer, 2003; 1998 DuPont Young Professor Award; 2002 Fellow, American Physical Society. Phone: (631) 632 7793 Fax: (631) 632 6518 Email: bhsiao@notes.cc.sunysb.edu Publications Ben Hsiao's Home Page

	Physical Chemistry,Polymer Physics and Materials Sciences   Polymers are long molecules having many unique properties different from metals and small-molecule liquids. They are widely used in our daily life in plastics, textile fibers and optical/medical devices. In my laboratory, we are interested in understanding the structural and morphological development and manipulation of complex polymer systems during preparation and processing in real time. The focus of our research projects is the design, preparation, characterization and application of nanostructured soft condensed materials, such as fibers (one-dimensional orientation), films (two-dimensional orientation) and bulk material systems (three-dimensional orientation), through precise control of molecular architecture and physical interactions including crystallization, molecular level mixing, deformation and flow. My current research programs are as follows.   Polymer Crystallization Fundamentals We are studying the mechanisms of the early stages as well as the late stages of polymer crystallization from the melt. Recently, several new hypotheses have been proposed to explain the initial stages of crystallization, which challenge the conventional view of crystallization through nucleation and growth processes. For example, one hypothesis suggests that density or orientation fluctuations form first in the melt, particularly through the process of spinodal decomposition, which serve as a precursor to crystallization. Our research group has carried out several fundamental research projects to verify these hypotheses.   Orientation-Induced Crystallization The behavior of orientation-induced crystallization in polymers under flow and deformation has been investigated using in-situ X-ray techniques. We propose that molecular orientation affects the crystallization behavior of polymer melts in two different aspects: thermodynamic and hydrodynamic. The thermodynamic effect involves the reduction of entropy in oriented chains, which favors the formation of primary nuclei with small size and large density that are mainly responsible for the increase of crystallization rate. The hydrodynamic effect generates the landscape of molecular orientation in chains with different molecular weights, which is responsible for the resultant morphology such as shish, kebab or spherulite. Several on-going projects are designed to explore the underlying physics of this subject.   Polymer Nanocomposites We are developing varying chemical and physical pathways to disperse nanostructured molecules (such as polyhedral oligomeric silsesquioxane (POSS) and carbon nanotubes) and nanosize particles (layered silicates or clays) in the polymer matrix at the molecular level. We found that the structure, property and processing relationships are dramatically different in nanocomposites as compared to their neat resin counterparts.   Absorbable Polymers for Medical Applications, Drug Delivery and Tissue Engineering We have developed several unique processing techniques to fabricate nanostructured materials including (1) nonwoven membranes consisting of nanosize fibers, and (2) nanosize particles (10 - 500 nm). FDA-approved biodegradable polymers such as polyglycolide (PGA) and polylactide (PLA) homo- and copolymers are the base materials for forming the nanostructured scaffolds. The biodegradation rate as well as the drug (DNA and medicine) release rate are functions of fiber/particle size, morphology, porosity and chemical compositions, which can be precisely controlled by processing parameters. The major goal of this research is for medical applications, drug delivery and tissue engineering.   Synchrotron X-ray Scattering and Diffraction Technology Development One unique characterization tool developed in this laboratory is the simultaneous small-angle x-ray scattering (SAXS) and wide-angle x-ray diffraction (WAXD) technique using synchrotron radiation. Dedicated to polymer research, the Advanced Polymers Participating Research Team (AP-PRT) was formed in 1997 to develop a synchrotron X-ray scattering beamline (X27C) at the National Synchrotron Light Source, Brookhaven National Laboratory. This facility, the first of its kind in the U.S., was funded by Stony Brook (Prof. B. Chu and I are spokespersons), NSLS, NIST, NIH, AFRL and four industrial laboratories (General Electric, Allied Signals, Montell USA, Hoechst Celanese). The primary focus of this PRT is to investigate polymer structure, morphology and dynamics from atomic (1-20 Å) to microscopic scales (20 - 1000 Å) in real time and/or in-situ using simultaneous SAXS/WAXD techniques.

University	Safety	Seminars	Library	Positions Available	Solar System	Molecules	Links