Three-dimensional micro fabrication of active micro devices using soft functional materials

Active materials that can adapt to dynamic environment have attracted growing attention in various fields of science and engineering because they hold great potential in development of autonomous and multifunctional devices and systems. Hydrogels, which swell and contract in response to a wide range of external stimuli, have been studied extensively as one of the most promising functional materials. Unique properties and advantages of these materials, however, have not been fully explored and successfully implemented at device level primarily because manufacturing and material process of this new class of materials still rely on conventional fabrication methods. This study presents development and application of a novel three-dimensional digital microfabrication technology, projection micro-stereolithography (P??SL), to engineer soft functional materials into reconfigurable active micro devices. Generation of complex motion is demonstrated by appropriate design of embedded microvascular network for direct solvent delivery in the polymeric device. Bio-inspired design principles of harnessing mechanical instability have been applied to improve actuation speed of soft devices and to create spontaneous structural pattern transformation. Fundamental mechanics on solvent diffusion kinetics and associated mechanical behavior of polymer is also investigated