讲座题目：Multifunctional Electroactive Polymer Devices

报告人：Prof. Q. M. Zhang

时 间：9月15日（周三）下午3:30
地 点：第二教学楼505 教室
主持人：董蜀湘 

报告内容摘要：
     What are the next generations of technologies? The direct and efficient coupling between the electric signals and the elastic, thermal, optical and magnetic signals in ferroelectric based electroactive polymers makes them attractive for exploiting a broad range of cross-coupling phenomena and applications which have the promise of great impact on totally new device technologies (see the figure).  This talk will present the recent advances in my group in advancing the electroactive polymers devices for charge storage, optic, and especially solid state cooling applications.  Making use of the proximity in energy between different phases which stability can be easily tuned by introducing “defects” in the polymers, we converted a normal ferroelectric P(VDF-TrFE) copolymer into a ferroelectric relaxor with a high dielectric constant and PVDF into a dielectric with reversible phase transformation between the polar- and non-polar phases, resulting in a high electric energy density (>25 J/cc) with fast discharge time (<1 ms).  The reversible phase transformation also leads to large E-O effect and by employing nano-composite approach to fine tuning the material properties, these polymers are promising for broadband optic communications. The high entropy states in these polymers also lead to giant electrocaloric effect, promising for high efficiency, compact, and environmentally friendly solid state cooling devices.