Soft materials, such as elastomers and gels, can be made active in that they can greatly change shape and volume in response to diverse stimuli. For example, a dielectric elastomer may strain more than 100% under an electric field. As another example, a gel may imbibe solvent molecules and swell thousand times its initial volume. These soft active materials (SAMs) are being developed in diverse technologies, including muscle-like actuators, drug delivery, and tissue engineering. This project will formulate field theories for SAMs subject to mechanical, electrical, and chemical loads. The theories will build on principles of nonlinear continuum mechanics, electrostatics, thermodynamics and kinetics. The project will link the field theories to experimental observations and to molecular models. One conspicuous hole in the courses of mechanics and materials is the lack of a substantive coverage of soft materials. The standard fare has not gone much beyond rubber elasticity. This hole may be filled through basic research in the context of emerging technologies. The PI has begun to incorporate recent advances in the mechanics of SAMs into a graduate course. The lecture notes have been placed online, and read by many people off the campus. In addition, SAMs are enabling many significant applications. Applications such as drug delivery and tissue engineering aim to address the long term societal needs for better health care. This project will help to bring the discipline of mechanics to participate in the creation of the technologies that will enhance the quality of our lives.
