CAREER: Mechanics of Damage-Tolerant Electro-Mechano-Chemically

这项教师早期职业发展（Career）资助将支持基础研究，以了解受头足类启发的耐损伤机电化学反应弹性体的颜色变化，自我修复和电变形的耦合。头足类动物的皮肤，同时具有变色的主动伪装，伤口和损伤的自我修复，以及神经元驱动的肌肉驱动，最近激发了各种工程应用的新型合成材料，从伪装皮肤，软机器人，柔性电子，热调节器到生物医学设备。尽管潜力巨大，但具有耦合特性的类头足类动物皮肤合成材料的设计仍处于没有理论指导的试错阶段。该项目将通过整合理论和实验来填补知识空白，为一种具有力诱导变色、自修复和机电驱动特性的新型合成弹性体的多物理场耦合提供机制和定量理解。从这个项目中获得的知识可能会促进未来水下机器人和飞行器伪装皮肤的创新。这项研究的见解也可能有助于设计价格合理的拟人化假肢和人工器官，以改善数百万残疾人的生活质量。此外，该项目还包括一个综合教育计划，通过多种途径培养不同群体的下一代工程师，包括工程课程开发，通过暑期研究项目让代表性不足的本科生和高中生参与，向骨科医院医学磁铁高中的K-12学生和教师推广，以及向洛杉矶博览中心的公众推广。合成弹性体由柔性聚合物网络组成，由自由基形成的机械载体二芳基二苯并呋喃酮交联，有望同时实现力诱导的颜色变化、自修复和机电驱动。该项目的中心假设是，聚合物网络连接的机械载体可以进行可逆的化学反应，以触发解离诱导的颜色变化和重新关联诱导的自我修复。在这一假设的驱动下，材料制造、多轴力学测试、机电驱动、机械致色测量以及相应的分析建模将集成在一起，揭示聚合物网络力学、断裂结合化学反应和机电相互作用的深刻多物理场耦合。具体任务包括：(1)了解合成弹性体的本构行为；(2)阐明弹性体在机械载荷作用下的变色与自愈耦合；(3)解码弹性体在机电载荷作用下变色、自愈与电变形的耦合。这项研究工作将为在可拉伸软材料的背景下，从机械和定量的角度理解多个物理场（力学、化学反应和电场）的反馈回路耦合开辟有希望的途径。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

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.