DMREF: Engineering the On-The-Fly Control of 3-D Printed Block Bottlebrush Assemblies via Dynamic Bonds and Materials Processing

生物学能够创造出具有真正复杂性质的材料;例如，变色龙可以通过影响纳米结构的方式拉伸皮肤来改变颜色，肌肉蛋白质可以可控地断裂和改革，以充当耗散能量的“减震器”。这些生物材料有一个共同的基本原理，即分子相互作用已经进化到精确控制纳米级结构和控制功能的动力学。然而，由于同时控制分子排列和运动的挑战，合成软材料很少达到这种复杂程度。这个设计材料来革命和工程我们的未来（DMREF）项目旨在通过使用处理来对分子相互作用进行空间和时间控制，从而通过动态“拨入”材料特性来弥合这一差距。这将通过使用3-D打印中的处理流程来控制分子组装，沿着化学键的断裂/重整以松弛或阻止材料结构来实现。自动打印和表征将通过机器学习协议促进材料发现，并将告知分子设计原则。这项跨学科的努力将汇集来自空军研究实验室（AFRL）的学术研究人员和科学家，他们结合了材料制造和表征，自动化合成和加工以及使用分子模拟和机器学习的专业知识。这项工作将利用纳米结构和动力学来创造模拟生物学中复杂功能的材料。这些新材料和加工能力将使社会和美国受益，因为它们可以在伪装、超材料、辐射冷却、能量转换和存储设备以及显示器等领域进行实时打印。该研究还将涉及培养学生的广泛专业知识，涵盖化学，工程和物理，通过学生辅导和教育推广，以学生从群体的历史上代表性不足的STEM领域。该项目将结合联合收割机的压力，在不平衡的3D打印过程中，沿着动态（例如，可逆的或可重复的）键合化学和可调的分子结构，以建立自动化制造/材料发现协议。一类被称为瓶刷嵌段共聚物的支化大分子可以形成纳米级组装体，其可以在施加的应力下变形并且对分支长度和密度敏感。这些材料特别有用，因为它们可以用化学官能团修饰，这些官能团通过瓶刷间的相互作用影响性能。根据材料基因组计划（MGI），该项目将建立一种方法，在这个丰富的设计空间中发现材料，使用计算机驱动的设计和物理引导的机器学习作为自动合成，表征和加工设计的补充。我们的目标是使用结构色作为具有可调“即时”纳米级结构的印刷材料的代表，并结合动态键合以冻结或暂时调节这些光学特性，并最终将刺激物-该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的智力价值和更广泛的评估来支持。影响审查标准。

Biology is capable of creating materials with truly complex properties; for example, chameleons can change their color by stretching their skin in ways that affect nanoscale structure, and muscle proteins can controllably break and reform to act as ‘shock absorbers’ that dissipate energy. These biological materials share a foundational principle, which is that molecular interactions have evolved to precisely control both the nanoscale structure and dynamics that govern function. Synthetic soft materials, however, rarely reach this level of sophistication due to the challenge of controlling both molecular arrangement and motions simultaneously. This Designing Materials to Revolutionize and Engineer our Future (DMREF) project seeks to bridge this gap by ‘dialing-in’ material properties on-the-fly by using processing to exert spatial and temporal control over molecular interactions. This will be achieved by using processing flows in 3-D printing to control molecular assemblies, along with breaking/reforming of chemical bonds to relax or arrest the material structure. Automated printing and characterization will facilitate materials discovery through machine learning protocols and will inform molecular design principles. This interdisciplinary effort will bring together academic researchers and scientists from the Air Force Research Laboratory (AFRL) who have combined expertise regarding making and characterizing materials, automating synthesis and processing, and using molecular simulation and machine learning. The effort will harness nanoscale structure and dynamics to create materials that emulate the complicated functions seen in biology. These new materials and processing capabilities will benefit society and the U.S. by on-the-fly printing new items with potential applications in camouflage, metamaterials, radiative cooling, energy conversion and storage devices, and displays. The research will also involve the training of students with broad expertise spanning chemistry, engineering, and physics, via both student mentorship and educational outreach to students from groups historically underrepresented in STEM fields.This project will combine the stresses in out-of-equilibrium 3D printing processes, along with dynamic (e.g. reversible or triggerable) bond chemistries and tunable molecular architecture, to establish an automated manufacturing/materials discovery protocol. A class of branched macromolecules known as bottlebrush block copolymers can form nanoscale assemblies, which can be distorted under an applied stress and are sensitive to branch length and density. These materials are especially useful because they can be decorated with chemical functional groups that affect properties via inter-bottlebrush interactions. In line with the Materials Genome Initiative (MGI), the project will establish a methodology to discover materials in this rich design space, using computer-driven design and physically-guided machine learning as a complement to automated synthesis, characterization, and processing design. The goal will be to use structural color as a proxy for printed materials with tunable ‘on-the-fly’ nanoscale structure, with dynamic bonding incorporated to freeze-in or temporally modulate these optical properties, and ultimately to incorporate stimuli-responsive functionality into these 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.