DMREF: Dynamic Control of 3-D Printed Hierarchical Soft Materials via Computation-Guided Molecular Design

3D 打印能够快速创建日常使用的精确形状的物品，从可定制的工程物品（例如车辆零件和制造原型）到患者特定的医疗设备（例如支架和假肢）。通过使用计算机编程指令，该技术目前能够制造具有微米精度的均匀物品。 3D打印已经是一项革命性的技术，但仍然无法创造出生命系统中真正先进的材料，这些材料可以通过改变长度尺度的结构来适应和改变刺激。例如，变色龙通过在纳米长度尺度上调整皮肤结构来改变颜色。这项研究旨在通过引入将材料结构调整至纳米尺度的新动态动态功能，显着推进 3D 打印的前沿发展。这种能力将通过设计自组装材料来实现，其中可以通过精确调整打印过程中的应力来控制自组装。这种方法将使变色龙皮肤状的材料能够快速适应颜色。这个跨学科团队汇集了材料制造、材料流动测试以及材料打印方面的专业知识。然后与先进的分子模拟相结合，设计和评估能够满足纳米级结构受控动态打印标准的可能材料。这些新材料将通过适应性印刷新产品，在迷彩、抗反射涂层、超材料和显示器方面具有潜在应用，从而造福社会和美国。该研究还将通过学生指导和对 STEM 领域代表性不足的学生的教育宣传，培训具有化学、工程和物理等广泛专业知识的学生。这项研究将利用非平衡 3D 打印过程中的应力来“拨入”打印结构中的分层结构特征。一类被称为“瓶刷嵌段共聚物”的候选材料可以形成在施加的应力下容易变形的纳米结构。洗瓶刷嵌段共聚物是一种有前途的材料平台，因为它们具有较大的分子设计空间。 PI 将开发并实施一种筛选方法来探索这一设计空间并确定分层可印刷材料的最佳洗瓶刷嵌段共聚物。计算机驱动设计的整体方法将结合可扩展合成、大规模模拟和流变表征，系统地设计聚合物分子，以产生所需的流动诱导纳米结构。该设计程序将用于“即时”优化 3D 打印纳米结构材料，最终对具有异质光子（即颜色）特性的 3D 打印材料进行概念验证。除了这一广泛目标之外，这项研究还将解决开发新的、可扩展的聚合物化学、驱动自组装和洗瓶刷嵌段共聚物流变学方面的基本问题。

3-D printing enables the rapid creation of precisely shaped items for everyday use, from customizable, engineered items such as vehicle parts and manufacturing prototypes, to patient-specific medical devices like stents and prostheses. Through use of computer programmed instructions, this technology is currently capable of making uniform items with micrometer precision. 3-D printing is already a revolutionary technology, but still cannot create the truly advanced materials found in living systems that adapt and transform upon stimulation by altering structures across length scales. For example, chameleons change their color by adjusting their skin structure at nanometer length scales. This research seeks to significantly advance the frontier of 3-D printing by introducing the new on-the-fly dynamic capability of tuning material structures down to the nanoscale. This capability will be achieved by designing self-assembling materials, where the self-assembly can be controlled by precisely adjusting the stresses in the printing process. This approach will enable chameleon-skin-like materials capable of rapid color adaptation to be made. This interdisciplinary team brings together expertise on making materials, testing how these materials flow, and printing these materials. This is then combined with advanced molecular simulation to design and evaluate possible materials capable of meeting the criteria for controlled on-the-fly printing of nano-scale structures. These new materials will benefit society and the U.S. by adaptably printing new items with potential applications in camouflage, antireflection coatings, metamaterials, 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 underrepresented in STEM fields.This research will use the stresses in out-of-equilibrium 3-D printing processes to 'dial-in' hierarchical structural features in printed structures. A class of candidate materials known as bottlebrush block copolymers can form nanometer structures that readily deform under an applied stress. Bottlebrush block copolymers are a promising materials platform because they possess a large molecular design space. The PIs will develop and implement a screening methodology to explore this design space and determine optimal bottlebrush block copolymers for hierarchical printable materials. A holistic approach to computer-driven design will combine scalable synthesis, large-scale simulation, and rheological characterization to systematically design polymer molecules to yield desired, flow-induced nano-structures. This design procedure will be implemented to optimize 3-D printed nanostructured materials 'on-the-fly', culminating in a proof-of-concept of 3-D printed materials with heterogeneous photonic (i.e. color) properties. Along with this broad goal, this research will address fundamental questions in developing new, scalable polymer chemistry, driven self-assembly, and the rheology of bottlebrush block copolymers.