Fabrication and Mechanical Behavior of Hierarchical Architected Metamaterials

该基金通过研究分层结构超材料的多光子光刻技术来支持先进制造业，为科学和技术进步提供了一条途径，为国家繁荣做出贡献。多光子光刻是一种增材制造技术，可以打印具有纳米级特征和分辨率的三维复杂结构。虽然光聚合过程中激光与材料相互作用的原理已经被很好地理解，但它们对打印材料机械性能的影响还没有被深入研究。这给这种结构的建模及其在功能材料系统中的应用带来了障碍。该奖项支持基础研究，以揭示多光子光刻对生物支架等3D结构的机械行为和有效设计的影响。该项目使这些结构的机械响应与加工参数的关系的准确建模。此外，它为多光子光刻的可扩展性及其在各种领域的应用铺平了道路，包括医疗保健，生物工程和航空航天。这项研究的结果构成了美国经济和社会的重要资产。这项研究涉及多个学科，包括制造、材料科学、力学和生物化学。这种多学科的方法对女性和少数族裔学生的工程教育产生了积极的影响。在纳米和微尺度上，多光子光刻（MPL）可以超越与制造极其复杂、机械坚固的三维（3D）结构有关的几个障碍。然而，阻碍该技术的可扩展性和广泛适用性的一个主要障碍是对制造材料的本构力学行为作为加工参数的函数的有限理解。本研究旨在了解MPL制造参数对分层结构超材料力学行为的影响。通过对缺陷形成的非原位TEM分析和原位SEM力学测试实验，对这些材料的力学性能进行了评估，包括延展性、强度、临界断裂韧性等性能，从而实现了这些材料的准确本构建模。这些模型包括有限元分析（FEA）和分子动力学（MD）模拟，以预测复杂3D结构的力学性能，并通过设计和制造具有多功能行为的生物支架来验证。表征实验的结果揭示了结构材料设计的增强力学性能和可扩展性，从而阐明了MPL的全部潜力。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 grant supports advanced manufacturing through a study of multiphoton lithography of hierarchical architected metamaterials, providing an avenue for both scientific and technological progress which contributes to national prosperity. Multiphoton lithography is an additive manufacturing technique that enables the printing of complex structures in three dimensions with nanoscale features and resolution. While the principles of laser-material interactions for photopolymerization are well understood, their effects on the mechanical properties of the printed material have not been studied thoroughly. This poses obstacles in the modeling of such structures and their utility in functional material systems. This award supports the fundamental research required to unravel the effects of multiphoton lithography on the mechanical behavior and efficient design of 3D structures such as bioscaffolds. This project enables accurate modeling of the mechanical response of these structures in relation to the processing parameters. Furthermore, it paves the way for the scalability of multiphoton lithography and its use in diverse fields, including healthcare, bioengineering, and aerospace. The results from this research constitute a critical asset in the U.S. economy and society. The research involves several disciplines, including manufacturing, materials science, mechanics, and biochemistry. This multi-disciplinary approach serves as a catalyst for positive impact in engineering education for women and underrepresented minority students.Multiphoton lithography (MPL) can surpass several barriers related to the fabrication of extremely complex, mechanically robust three-dimensional (3D) structures in nano- and microscale. However, a major obstacle hindering advance of the scalability and wide applicability of this technique is the limited understanding on the constitutive mechanical behavior of the fabricated materials as a function of the processing parameters. This research is designed to comprehend the effect of MPL fabrication parameters on the mechanical behavior of hierarchical architected metamaterials. Through ex situ TEM analysis of defect formation and in situ SEM mechanical testing experiments, the mechanical performance of these materials is evaluated with respect to properties such as ductility, strength, critical fracture toughness and therefore enable accurate constitutive modeling of these materials. These models involve finite element analysis (FEA) and molecular dynamics (MD) simulations towards predicting the mechanical performance of complex 3D structures, validated through the design and manufacture of bioscaffolds that can possess multifunctional behavior. The results of the characterization experiments are used to reveal the enhanced mechanical performance and scalability of the architected material designs, thereby elucidating the full potential of MPL.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.