北京时间11月19日晚八点，iCANX Youth Talks第八十二期将隆重开播！本期，我们邀请到了加州大学洛杉矶分校博士后吴瀚翔、宾州州立大学博士后芮冠淳、南开大学博士薄轶文主讲，剑桥大学Newton International Fellow 郭梦帆、加州大学洛杉矶分校博士祝媛担任研讨嘉宾，加州大学洛杉矶分校博士后吴瀚翔担任主持人，期待你一起加入这场知识盛宴。
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嘉宾介绍
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吴瀚翔
加州大学洛杉矶分校
基于双功能弛豫铁电聚合物的自我再生热泵
Electrocaloric (EC) cooling presents a promising approach to efficient and compact solid-state heat pumps. However, reported EC coolers have complex architectures and limited cooling temperature lift. In this talk, I will introduce a self-regenerative heat pump (SRHP) using a cascade of EC polymer film stacks, which have electrostrictive actuations in response to an electric field that are directed to realize efficient heat transfer, eliminating the need for additional transportive or regenerative mechanisms. The SRHP demonstrates a cooling of 8.8 kelvin below ambient temperature in 30 seconds and delivers a maximum specific cooling power of 1.52 watts per gram. The temperature lift of the SRHP is 14.2 kelvin. These results underscore the potential of the compact solid-state cooling mechanism to address the increasing need for localized thermal management. I will also talk about a study on the microscopic origin of the electrocaloric effect. A Fourier transform infrared spectroscopy equipped with a high voltage source is used to operandoly observe the characteristic molecular vibrational modes. This work resolves the molecular origins of the large entropy change behind the electric field-induced dipole switching.
电卡（Electrocaloric）制冷提供了一种高效且紧凑的固态热泵方案。然而，现有的电卡制冷器件结构复杂且制冷温差有限。我将在报告中介绍一种自我再生热泵（SRHP），其采用级联电卡聚合物薄膜，通过电致伸缩效应实现高效的热传递，无需额外的传输或再生机制。SRHP在30秒内可将温度降低至比环境温度低8.8开尔文，并提供最大1.52瓦每克的单位质量制冷功率。SRHP两端的最大温差为14.2开尔文。这些结果凸显了紧凑型固态制冷在应对日益增加的局部热管理需求方面的潜力。此外，我还将介绍关于电卡效应微观机制的研究工作。该工作使用配备高压源的傅里叶变换红外光谱仪进行原位表征，实时观察特征分子的振动模式。这揭示了电场引发偶极子定向排列是电卡效应熵变的分子起源。
Dr. Hanxiang Wu is currently a postdoctoral researcher at the University of California, Los Angeles. He obtained his Bachelor’s degree from Microelectronics Science and Engineering department at Peking University, and the PhD degree from Materials Science and Engineering department at University of California, Los Angeles. His research interest includes electrocaloric materials and devices, and wearable electronics. He has published over 20 articles in international journals including Science, Advanced Functional Materials, Matter, Nano Energy, Journal of Materials Chemistry A, etc.
吴瀚翔博士是加州大学洛杉矶分校材料科学与工程系博士后。他2018年本科毕业于北京大学微电子科学与工程系，2023年博士毕业于加州大学洛杉矶分校材料科学与工程系。主要研究方向包括电卡材料与器件、可穿戴电子器件，在Science, Advanced Functional Materials, Matter, Nano Energy, Journal of Materials Chemistry A等国际期刊上发表20余篇SCI论文。
芮冠淳
宾夕法尼亚州立大学
铁电聚合物中电活性的来源探究
Despite decades of research on ferroelectric polymers, the origin of polymer piezoelectric, electrostrictive and electrocaloric properties (electroactive properties) is still under debate. Combined with the fact that their comprehensive electric performance is much worse than the ceramic counterparts, such as barium titanate and lead zirconate titanate, this has hampered the development of high-performance ferroelectric polymers and their practical applications. Recently, we have discovered that the complex semicrystalline structure of ferroelectric polymers plays an important role. Namely, the electrostriction of the oriented amorphous fraction (OAF), which links between the primary crystalline lamellae and the isotropic amorphous fraction (IAF), is the origin of the above-mentioned electroactive properties of ferroelectric polymers. For example, we have achieved high piezoelectric coefficients (both d31 and d33) in the range of 60-80 pC/N for ferroelectric polymer, compared with the commercialized materials with <30pC/N. This understanding will help us design new ferroelectric polymers with even higher performance and better applications.
尽管人们对铁电聚合物进行了几十年的研究，但聚合物的压电、电致伸缩和电卡性能（电活性性能）的来源仍然存在争议，加之其综合介电性能远不如钛酸钡、锆钛酸铅等陶瓷材料，这阻碍了高性能铁电聚合物的开发和实际应用。最近，我们发现铁电聚合物中的复杂半结晶结构对上述电活性性能起着重要作用。我们发现了取向非晶态部分（OAF）的电致伸缩是铁电聚合物电活性性能的来源。并找出了OAF连接片层晶体晶和完全无规无定形部分（IAF）的结构性证据。基于新开发的三相理论模型，我们实现了铁电聚合物压电性能的显著提升（压电系数60-80 pC/N相比于传统材料低于30pC/N。这种理解将帮助我们设计出性能更佳、应用更广的新型铁电聚合物。
Dr. Guanchun Rui is currently a postdoctoral scientist at Arkema Inc. He is also a visiting scientist at the Pennsylvania State University. He received his B.S. degree from Beijing University of Chemical Technology in 2018, and Ph.D. degree from Case Western Reserve University in 2023. His current research interests are dielectrics and electroactive polymers, including the relationship between the structure and their piezoelectric, electrostriction and electrocaloric properties. In recent five years, He published more than 30 international peer-reviewed papers, including Nature, Advanced Materials, Nature Communications, Energy & Environmental Science，Matter, Nano Energy, Macromolecules, etc. He serves in the youth editorial board for Responsive Materials. He is also a qualified proposal reviewer for Center for Functional Nanomaterials (CFN), U.S. Department of Energy (DOE).
芮冠淳博士目前担任Arkema公司（美国）博后科学家，也是美国宾夕法尼亚州立大学访问学者。2018年本科毕业于北京化工大学高分子材料与科学系，2023年博士毕业于美国凯斯西储大学大分子科学与工程系。主要研究方向为介电和电活性材料，包括铁电聚合物的结构与其压电、电致形变、和电卡性能关系。近五年在Nature, Advanced Materials, Nature Communications, Energy & Environmental Science，Matter, Nano Energy, Macromolecules等国际期刊上发表文章30余篇。他目前担任Responsive Materials期刊青年编委，并担任美国能源部（DOE）功能纳米材料中心（CFN）基金评委(2024-2026)。
薄轶文
南开大学
基于聚合物电卡效应的功能器件研究
The commonly used vapor compression thermal management system struggle to meet the growing demands for miniaturization and wearability. The inherent flexibility of polymer electrocaloric (EC) materials and their ultrafast temperature change under square wave voltage signals offer significant potential in the fields of miniaturized and wearable thermal management. In this presentation, I will introduce attempts to apply the EC effect of polymer materials in human thermal management, temperature control of CPU, and ultrafast thermal camouflage. The EC thermal management device using electrostatic actuation is one of the most efficient EC devices available, by integrating with organic photovoltaic module and energy storage system can enable self-sustaining human thermal management. Further modifications and device cascade technique can enhance the thermal management capability. Additionally, we have explored the coupling of the EC effect with thermochromic effects, demonstrating its potential for fast camouflage applications. Through these examples, we aim to broaden the application scenarios of polymer EC materials.
目前常用的蒸汽压缩热管理装置难以满足日益增加的小型化及可穿戴需求。聚合物电卡材料的本征柔性及在方波电压信号下的超快温度变化特性为其在小型化及可穿戴热管理领域提供了很多可能。在这次报告中，我将介绍利用聚合物材料的电卡效应在人体热管理、芯片控温、以及快速伪装领域的应用尝试。利用静电驱动P(VDF-TrFE-CFE)薄膜进行冷热分离的装置是目前最高效的电卡热管理装置之一，与有机光伏模组以及储能模块集成可以实现自持续人体热管理。进一步对薄膜材料进行改性以及制备级联器件等可以实现控温能力的进一步提升。另外，我们还利用了电卡效应与热致变色效应的耦合展示了其在快速伪装领域的应用潜力。通过这些例子，我们希望能进一步拓宽聚合物电卡材料的应用场景。
Bo Yiwen is a PhD student at the School of Materials Science and Engineering, Nankai University. He received his B.E. degree at Tianjin Polytechnic University in 2018, under the supervision of Professor Na Han, engaged in cellulose-based solid-solid phase change materials. Since 2018, he has been pursuing a combined master's and doctorate program at Nankai University, under the supervision of Professor Rujun Ma. His primary research focus on the development of polymer electrocaloric materials and their applications in solid-state thermal management systems, including energy-efficient cooling devices, heat control technologies, and advanced thermal management solutions for electronics and wearable devices. His researches have published in Science, Joule, Advanced Energy Materials, etc.
薄轶文是南开大学材料科学与工程学院的在读博士。2018年本科毕业于天津工业大学材料科学与工程学院，导师韩娜教授，从事纤维素基固-固相变材料的探索。2018年以后硕博连读于南开大学材料科学与工程学院，导师马儒军教授。主要研究方向为聚合物电卡材料的开发及其在固态热管理系统中的应用，包括节能冷却设备、热控制技术以及电子和可穿戴设备的先进热管理解决方案并在Science、Joule、Advanced Energy Materials等国际期刊上发表了研究工作。
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主持人
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吴瀚翔
加州大学洛杉矶分校
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研讨嘉宾
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郭梦帆
剑桥大学
祝 媛
加州大学洛杉矶分校
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