This Faculty Early Career Development (CAREER) grant will support fundamental research to understand the coupling of color-change, self-healing, and electro-deformation of a cephalopod-inspired damage-tolerant electro-mechano-chemically responsive elastomer. Cephalopod skins, simultaneously featuring color-change for active camouflage, self-healing of wounds and injuries, and neuron-driven muscle actuation, have recently inspired novel synthetic materials for diverse engineering applications, ranging from camouflage skins, soft robotics, flexible electronics, and thermal regulators, to biomedical devices. Despite the great potential, the design of cephalopod-skin-like synthetic materials with coupled properties remains at the trial-and-error stage without theoretical guidance. This project will fill the knowledge gap by integrating theories and experiments to provide a mechanistic and quantitative understanding of the multiphysics coupling of a new synthetic elastomer with properties of force-induced color-change, self-healing, and electro-mechanical actuation. The knowledge obtained from this project may facilitate innovations of future camouflage skins for underwater robotics and aerial vehicles. The insights from this research may also help the design of affordable anthropomorphic prostheses and artificial organs to improve the life quality of millions of disabled people. Besides, the project includes an integrated education plan to train diverse groups of next-generation engineers through a variety of avenues, including engineering curriculum development, involvement of underrepresented undergraduates and high school students via summer research programs, outreach to K-12 students and teachers at Orthopaedic Hospital Medical Magnet High School, and outreach to the general public at Los Angeles EXPO Center.
The synthetic elastomer consists of flexible polymer networks crosslinked by radical-forming mechanophores diarylbibenzofuranone, expecting to simultaneously enable force-induced color-change, self-healing, and electro-mechanical actuation. The central hypothesis of the project is that the polymer-network-linked mechanophores can undergo a reversible chemical reaction to trigger dissociation-induced color-change and re-associated-induced self-healing. Driven by the hypothesis, material fabrication, multiaxial mechanical testing, electromechanical actuation, mechanochromic measurement, and corresponding analytical modeling will be integrated to reveal the profound multiphysics coupling of polymer network mechanics, scission-binding chemical reactions, and electro-mechanical interactions. Specific tasks include: (1) to understand the constitutive behavior of the synthetic elastomer, (2) to elucidate the coupling of color-change and self-healing of the elastomer under mechanical loads, and (3) to decode the coupling of color-change, self-healing, and electro-deformation when the elastomer is under electro-mechanical loads. The research effort will open promising avenues for mechanistically and quantitatively understanding a feed-back-loop coupling of multiple physical fields (mechanics, chemical reaction, and electric field) within the context of stretchable soft materials.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
