美国Duke大学Yong YANG（杨勇）博士学术报告

    应化学工程国家重点实验室（浙江大学）邀请，美国Duke大学Yong YANG（杨勇）博士将于2008年4月29日访问本室，并作学术报告。

   报告题目: Polymer Nanoengineering for Industrial and Biomedical Applications

   报告时间：2008年4月29日（星期二）上午9:00

   报告地点：玉泉校区教十2102室

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报告简介

Polymer dynamics at the nanoscale is of importance in coatings, electronics, lithography, composites, and biocompatible materials. At the nanoscale, polymer-free surface and/or polymer-substrate interactions contribute greatly to the properties of polymers. Depending on the entropic and enthalpic effects of the interface, the nanoconfined polymer shows different thermomechanical behavior.
In this work, we investigate substrate effects on polymer thin films as an analogy for polymer nanocomposites. Polystyrene (PS) thin films were spun-coat onto graphite and silicon oxide surfaces to resemble the polymer-substrate interface in carbon and organoclay based nanocomposites. The film thickness was varied and the apparent glass transition temperature ( T g ) was investigated using atomic force microscope (AFM) with nanoparticles as the probe. The PS on these substrates shows different T g profiles, depending on the polymer-substrate interactions. The influence of carbon dioxide (CO 2 ) on the T g profile of these thin films was examined as well. Neutron reflectivity and AFM studies show that introducing CO 2 , even at low pressures, largely enhances chain mobility and tends to alleviate the substrate confinement. These results provide valuable guidance for designing and processing new polymer nanocomposites.
A low-temperature assembly method for polymeric micro/nanostructures has been developed based on low pressure CO 2 -enhanced chain mobility at the nanoscale. By regulating CO 2 pressure, we successfully demonstrated the assembly of polymeric micro/nanostructures at low temperatures, even at biologically permissive temperatures. Furthermore, this assembly was realized in an aqueous environment in the presence of cells and biomolecules. Original structures are well preserved and CO 2 pressure has little effect on the bioactivity/viability and functionalities of the proteins, DNAs, and cells studied. This CO 2 -assisted assembly method provides for a highly affordable manufacturing platform that, thus far, has been lacking in the fields of tissue engineering, cell-based biochips, cell therapy, and drug delivery.

Dr. Yong Yang is currently a research associate in Biomedical Engineering Department at Duke University . His research is focusing on developing well-defined three-dimensional cell culture platform through the application of polymer micro- and nanotechnology as well microfluidics, eventually for stem cell technology and regenerative medicine. Prior to moving to Duke, Dr. Yang was in The National Science Foundation (NSF) sponsored Nanoscale Science and Engineering Center (NSEC) for Affordable Nanoengineering of Polymer Biomedical Devices (CANPBD) at The Ohio State University, where he was leading the Non-Cleanroom Affordable Nanoengineering Technology Thrust Area. This thrust area aims at developing polymer-based low-cost nanofabrication technologies that can be used to produce nanofluidic devices and multifunctional polymer-nanoparticle-biomolecule nanostructures for the next generation medical diagnostic and therapeutic applications. Dr. Yang obtained his Ph.D. from The Department of Chemical and Biomolecular Engineering at The Ohio State University and BS and MS from Zhejiang University . Dr. Yang's research interests include stem cell technology, polymer micro/nanotechnology, polymer nanocomposites and supercritical fluids technology.

 

    化学工程国家重点实验室（浙江大学）
2008年4月21日