Design of Tough Resilient Gels Using Adhesive Rigid-Rod Polymers

摘要：该项目将确定强弹性聚合物材料的最佳设计参数，以提高其在广泛应用中的应用，包括作为可在失效后愈合的智能结构材料，作为受损关节的组织替代品，以及作为大规模制造干细胞培养物的支架。我们的研究利用了蛋白质基聚合物的独特特性来制造具有增强韧性和弹性的材料。我们的研究结果不仅将提供优化标准，而且将建立分子结构与体积、宏观材料响应之间的关系。在长度尺度之间建立这样的联系是非常重要的，并且将使其他学术和工业工程师能够利用我们的工作来解决材料科学中的许多问题。这项研究将吸引研究生、本科生和社区学院的学生参与材料研究，同时提供最先进的实验和计算方法的实践训练。学生和PI将参加社区外展活动，并访问当地小学，以促进公众对前沿材料科学的理解。技术摘要：本项目将通过建立粘接刚性棒聚合物网络中结构和力学之间的关系，改进强弹性聚合物材料的设计。我们使用的模型系统是由一种叫做微管的丝状细胞蛋白质组成的，它的化学和机械特性我们可以严格控制。实验上，我们利用聚焦电磁场对这种网络施加局部力来操纵微尺度粒子，并将粒子位移与凝胶的局部力学特性联系起来。与大多数合成系统不同，基于蛋白质的网络非常刚性，允许它们保留其初始，卸载状态的内在记忆。此外，基于蛋白质的交联剂是不稳定的：它们的键在外力作用下断裂，但在外力移除时又能重新形成。这些独特的特性增加了生物材料的韧性和弹性，并允许这些材料“愈合”，即使它们局部加载失败。通过实验和模拟，我们的工作将建立材料反应的微观起源，并将指导耐用，适应性和自我修复的仿生材料的开发。这种材料可以用作人工组织或智能结构材料，在负载下需要减震。这项工作将吸引研究生、本科生和社区学院的学生参与材料研究。学生们和PI将参加当地小学的社区外展活动，以促进公众对前沿材料科学的理解，并将通过出版物、会议和亲自访问当地学校来广泛分享我们的成果。

Non-technical Abstract:This project will determine the optimal design parameters for strong, resilient polymeric materials to improve their use in a wide range of applications including as smart structural materials that can heal after failure, as tissue replacements for damaged joints, and as scaffolds for the large-scale manufacture of stem cell cultures. Our study takes advantage of the unique features of protein-based polymers to create materials with enhanced toughness and resiliency. Our results will provide not only optimization criteria, but will establish the relationships between molecular structure and bulk, macroscopic material response. Building such connections between length scales is very important, and will enable other academic and industrial engineers to leverage our work to solve numerous problems in materials science. This study will engage graduate, undergraduate and community college students in materials research, while providing hands on training in state-of-the-art experimental and computational methods. The students and the PI will participate in community outreach events and visits to local elementary schools to advance a public understanding of cutting edge materials science.Technical Abstract:This project will enable the improved design of strong, resilient polymeric materials by establishing the relationships between structure and mechanics in adhesive rigid rod polymer networks. We use a model system made of filamentous cellular proteins called microtubules with chemical and mechanical properties we can tightly control. Experimentally, we apply local forces to such networks using focused electromagnetic fields to manipulate microscale particles and we relate particle displacement to understand the local mechanical properties of the gels. Unlike most synthetic systems, protein-based networks are very rigid allowing them to retain an intrinsic memory of their initial, unloaded state. Moreover, protein-based crosslinkers are labile: their bonds break under force but can reform when the force is removed. These unique features increase biomaterial toughness and resiliency, and allow such materials to 'heal', even when they are locally loaded to failure. Through experimentation and simulation, our work will establish the microscopic origins of material response, and will guide the development of bio-inspired materials that are durable, adaptive, and self-healing. Such materials could be used as artificial tissues or as smart structural materials where shock absorption under loading is required. This work will engage graduate, undergraduate and community college students in materials research. The students and the PI will participate in community outreach events at local elementary schools to advance a public understanding of cutting edge materials science and will share our results broadly through publications, conferences, and in-person visits to local schools.