Posted on behalf of Rosamund Daw (Senior Editor, Nature)
At the Fall MRS meeting this year we are enjoying unusually mild weather. I can remember Christmassy snow at MRS’s past where woolly hats were a must. This year, many of the attendees are wandering around without coats and I have even spotted one or two brave individuals wearing T-shirts.
Two major themes at this year’s meeting are energy and the interface of materials with biology and medicine. An intriguing presentation from Philseok Kim on Monday combined these themes in a talk describing a bio-inspired approach to improve the energy efficiency of buildings. [Adaptive and dynamic optical materials for improving energy efficiency of buildings; Kim, P., Kolle, M., Khan, M., Zarzar, L.D., Aizenberg, J.; Symposium V (Multifunctional Polymer-based Materials); 2011 MRS Fall Meeting].
Kim reflected on the concerted motion of cilia in lungs, and other hairy or high-aspect-ratio biological structures which respond and adapt to different environments. He has designed a biomimetic system in which polymeric ‘hairs’ are embedded in a hydrogel. The hydrogels can elicit a tunable response to a variety of stimuli, for example temperature, causing the hairs to stand on end or lie flat against their substrate.
Kim proposed that these structures could be used to improve the energy efficiency of buildings. Extended transparent arrays of hairs could be arranged in panels across windows. Once the temperature outside dropped to a certain level, changes in the molecular conformation of the hydrogels would stimulate the hairs to stand on end simultaneously mobilising an array of deformable micromirrors attached to their ends into a single flat panel to control light transmission, reflection and thermal gain.
I like the work because it applies biomimetics in a rather unexpected way. The final goal offers engineering challenges because effects on the molecular scale are used to elicit functionality on the metre scale. Still, if achieved, such ‘smart curtains’ could reduce need for energy-intensive heating and cooling of buildings.