ME Seminar on “Warm-blooded Plastics” Bio-inspired Solutions to Smart Material Systems

Wednesday, March 6, 2013 - 10:00am to 11:00am
**ESB 2001**

Speaker: 

Dr. Ximin (Tracy) He, Wyss Institute for Biologically Inspired Engineering, School of Engineering and Applied Science, Harvard University

Abstract:  Creating smart systems that efficiently convert energy by sensing and responding to environmental stimuli and chemical signals on both a microscopic and macroscopic level has been a longstanding scientific pursuit, especially given the global challenges in energy and healthcare nowadays. But from a biological perspective, the interplay between the electrical or chemical stimuli, the solar energy from sunlight, and the mechanical motion is commonplace, indeed fundamental, to nature’s abilities of self-regulation via the effective energy harvesting and conversion on both a microscopic and macroscopic level. Warm-blooded animals and many living organisms exhibit unique homeostatic abilities, maintaining tight control of their local environment (temperature, pressure, etc.) through efficient interconversions of chemical and mechanical energy via self-regulating feedback loops. In contrast, most man-made materials lack this capability. Applying the concept of homeostasis to the design of autonomous materials would have substantial impacts in areas ranging from ‘smart’ materials that regulate energy usage in batteries or energy-efficient buildings to medical implants that help stabilize bodily functions. This talk will present a versatile strategy for creating self-regulating, self-powered, homeostatic materials capable of precisely tailored chemo-mechano-chemical feedback loops on the nano- or micro-scale. The exemplary autonomous, self-sustained polymer-based material systems “SMARTS” are able to maintain a user-defined parameter, for example temperature, in a narrow range, by employing a continuous feedback loop between various catalytic reactions and the mechanical action of the environmentally-responsive material hydrogel. The bio-inspired adaptively reconfigurable materials uniquely combine muscle-like stimuli-responsive material, hydrogel with high-aspect ratio (HAR) structured, passive skeletal materials, which are able to reversibly reconfigure, providing a means to switch surface topographic, physical and also chemical properties in response to environmental cues. This broad-based dynamically adaptive platform is highly customizable owing to the broad choice of chemistries, tunable mechanics and its physical simplicity. Perspectives on the bio-inspired solutions to innovating bio-inspired smart material systems will be discussed, from smart devices for solar energy harvesting and clean energy generation to energy-efficient materials.

Bio:  Ximin He is a postdoctoral research fellow in Wyss Institute of Bioinspired Engineering and School of Engineering and Applied Science in Joanna Aizenberg group at Harvard University. She received her PhD in Chemistry in the fields of Nanoscience and Organic Optoelectronics from University of Cambridge, Melville Laboratory for Polymer Synthesis, Cavendish Laboratory and Nanoscience Center. Dr. He’s research focuses smart materials, organic optoelectronics, as well as biologically inspired engineering technologies with applications in materials science, biomedicine, and energy. She has authored/co-authored 19 papers in leading archival journals and peer-reviewed conference proceedings, a book chapter and has a number of pending U.S./U.K. patents. Dr. He is the recipient of the Gates Cambridge Scholarship, UK Overseas Research Scholarship, the Government Award for National Outstanding Students, and National Excellent Young Scientist Award by the W. Wing Yip & Brothers Bursaries. Her research on novel nanostructured polymeric solar cells and bioinspired synthetic homeostatic materials have garnered a number of regional and international Best Student Paper awards and Best Poster award in the MRS meeting, and was featured in >100 international news outlets, including The Times, BBC, and Nature.