CAREER: Rational Design and Manufacturing of Nanostructured Surfaces and Interfaces in Lightweight Materials

该学院早期职业发展计划(Career)奖支持轻质结构材料(包括聚合物基复合材料和轻质镁合金)可扩展制造的基础研究。这笔赠款旨在开发新的表面修饰技术，依赖于原子层沉积(ALD)，这种技术可以沉积亚单层厚层，作为种子，随后在纳米级生长新结构-三维结构。这些设计的纳米结构非常多才多艺。它们可以提高聚合物复合材料的强度，允许轻质材料，并防止金属表面的腐蚀。例如，这解决了运输部门在保持安全的同时提高燃油效率和车辆性能的关键需求。除了对轻量化的直接影响外，产生的科学知识将为自下而上的纳米级设计和制造提供另一种设计范例。教育目标是提高公众对纳米材料对国内制造业未来的重要性的认识。该教育计划将设计和制造、纳米技术和表面科学的概念整合到多个层次，包括新的六年级材料课程，将材料教育整合到本科生团队指导中，并通过研究示范促进更多样化的STEM劳动力，以鼓励未被充分代表的学生申请研究生院并参与研究。目前用于控制块状结构材料表面和界面结构的制造工艺存在着对几何参数(如特征尺寸、形状、几何取向)控制不佳的问题，这在非平面表面上纳米材料的分级组装中尤其具有挑战性。缺乏对结构的确定性控制限制了我们从根本上了解纳米结构如何产生特定材料特性的能力，以及合理设计优化结构以实现特定应用特性的途径。该项目的努力通过定量确定在纳米尺度上实现界面几何形状和组成的确定性控制所需的过程-结构关系来解决这一限制。该方法使用空间ALD的概念，通过基于溶液的过程来生成亚单层种子区，用于纳米结构的生长。可以重复这一过程，在表面形成三维纳米结构，以精确调整轻质结构材料的界面几何形状、组成和微观结构，并量化对其机械性能和耐腐蚀性的影响。对这些过程-结构关系的更好理解将提供编码所需的基础知识。将纳米级构建块控制分层组装成表面体系结构的制造说明书。这一方法将被用来解决轻质结构材料方面的两个关键挑战：1)聚合物基复合材料中纳米结构中间相的合理设计，以调整其机械性能，以及2)提高镁合金的耐腐蚀性。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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 Program (CAREER) award supports fundamental research on scalable manufacturing of lightweight structural materials including polymer-matrix composites and lightweight magnesium alloys. The grant looks to develop new surface modification techniques, relying on atomic layer deposition (ALD) which can deposit sub-monolayer thick layers which serve as seeds to subsequently grow new structures three-dimensional structures at the nanoscale. These designed nanostructures are remarkably versatile. They can serve to improve the strength of polymer composites allowing for light-weight materials as well as impede corrosion on metal surfaces. This addresses critical needs, for example, in the transportation sector to improve fuel efficiency and vehicle performance, while maintaining safety. Beyond the direct impact on lightweighting, the scientific knowledge generated will provide an alternative design paradigm to the bottom-up design and manufacturing at the nanoscale. The educational goal is to promote public awareness of the importance of nanomaterials for the future of domestic manufacturing. The educational plan integrates concepts of design and manufacturing, nanotechnology, and surface science across multiple levels, including a new 6th grade materials curriculum, integrating materials education into undergraduate student team mentorship, and promoting a more diverse STEM workforce through research demonstrations to encourage underrepresented students to apply to graduate school and participate in research.Current manufacturing processes for controlling surface and interfacial structure in bulk structural materials suffer from poor control of geometric parameters such as feature size, shape, geometric orientation, which is particularly challenging within hierarchical assemblies of nanomaterials on non-planar surfaces. This lack of deterministic control of structure limits our ability to fundamentally understand how the nanostructuring produces specific material properties and a route to rationally design optimized structures to achieve application-specific properties. This project's effort addresses this limitation by quantitatively identifying the process-structure relationships needed to achieve deterministic control of interfacial geometry and composition at the nanoscale. The approach uses the concept of spatial ALD to generate sub-monolayer seeding areas for the growth of nanostructures through solution-based processes. The process can be repeated to develop three dimensional nanostructures on surfaces to precisely tune the interfacial geometry, composition, and microstructure of lightweight structural materials, and quantify the impact on their mechanical properties and corrosion resistance. An improved understanding of these process-structure relationships will provide the fundamental knowledge needed to ?encode? the manufacturing instructions for the controlled hierarchical assembly of nanoscale building blocks into surface architectures. This approach will be used to address two critical challenges in lightweight structural materials: 1) rational design of nanostructured interphases in polymer matrix composites to tune their mechanical properties, and 2) improving corrosion-resistance of magnesium alloys.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.