CAREER: Engineering Designer Composite Materials -- Magnetically Controlling Filler Alignment of Oblate Spheroids in Novel Thermoset Metamaterials

CBET-1652958PI：Walker，Travis W。这个职业奖项的目标是发展一个教育和研究的综合计划，专注于创造新型超材料，这是一种先进的复合材料，表现出自然材料中通常没有的特性。超材料通常是通过将填充颗粒添加到基材中而产生的，例如聚合物材料。如果填料颗粒的大小、形状和取向可以精确控制，那么材料的宏观特性，如其强度或硬度，就可以以新的方式进行定制。该项目将使用磁场来控制填充颗粒，例如已经在初步实验中使用的磁性微盘。该项目将开发理论模型，以帮助确定工程复合材料的新策略。实验和理论将验证这样的假设，即通过控制亚微米填料颗粒的取向时间和复合材料的凝固过程，可以在亚微米尺度上设计超材料。该项目的结果可以通过寻找通过复合材料在空间上改变性能的方法来帮助推进添加剂制造。该项目将包括为K-12和大学参与者开发新的模块和实践活动，并在名为“通过实践服务学习探索物理的魔力”的新课程中进行。此外，研究小组将利用他们实验室中的3D打印能力，为高中学生和教师开发3D建模和打印工作坊。复合超材料将通过在牛顿流体中排列二维磁性粒子(即磁盘)，同时控制粒子的质量分布来制造。颗粒的大小、形状、取向、浮力、磁化率和浓度预计都会影响排列动力学和破坏的形成，例如颗粒链，这可能会导致材料中不希望看到的不均匀。这些实验将包括使用一种新型的磁镊子装置，利用旋转磁场来研究排列。我们将研究不同磁场条件下的两粒子相互作用。然后，测量胶体悬浮液的流变性，以确定颗粒形状和取向的影响。将确定在防止链形成的同时使填充物颗粒磁性对准的策略。然后，将开发一套系统地分析块体各向异性复合材料取向和聚合过程中的控制参数的装置。基于连续介质的颗粒在体力作用下在粘性流体中运动的理论描述将有助于解释实验数据，为填料颗粒的设计提供洞察，并指导先进复合材料的精密工程。具有精确排列填充物的纳米复合材料将在创造先进的生物材料、光学、电磁和薄膜技术方面提供新的创新机会。

CBET - 1652958PI: Walker, Travis W.The goal of this CAREER award is to develop an integrated program of education and research focused on the creation of novel metamaterials, which are advanced composite materials that exhibit properties not usually found in naturally occurring materials. Metamaterials are often created by adding filler particles to a substrate, such as a polymeric material. If the size, shape, and orientation of the filler particles can be precisely controlled, then macroscopic properties of the material such as its strength or stiffness, can be tailored in novel ways. This project will use magnetic fields to control filler particles, such as magnetic microdisks that have been used in preliminary experiments. The project will develop theoretical models to help identify novel strategies for engineering composite materials. The experiments and theory will test the hypothesis that metamaterials can be designed on the sub-micron length scale by controlling the alignment time of submicron filler particles and the solidification of the composite. Results from the project could help advance additive manufacturing by finding ways to vary properties spatially through a composite material. The project will include development of new modules and hands-on activities for K-12 and college participants in a new course titled, "Exploring the Magic of Physics via Hands-on Service Learning." Furthermore, the research team will leverage the use of 3D printing capabilities in their laboratory to develop workshops on 3D modeling and printing for high-school students and teachers.Composite metamaterials will be fabricated by aligning two-dimensional magnetic particles, i.e., disks, in Newtonian fluids while controlling the center of mass distribution of the particles. The size, shape, orientation, buoyancy, susceptibility, and concentration of the particles are each expected to influence alignment dynamics and the formation of disruptions, such as the particle chaining, which could lead to unwanted heterogeneity in the material. The experiments will involve the use of new kind of magnetic tweezer apparatus for investigating alignment using a rotating magnetic field. Two-particle interactions under various magnetic field conditions will be examined. Then, the rheological properties of colloidal suspensions will be measured to determine influences of particle shape and orientation. Strategies will be identified for magnetically aligning filler particles while preventing chain formation. Then, an apparatus will be developed to systematically analyze control parameters during alignment and polymerization of bulk anisotropic composites. Continuum-based theoretical descriptions for particle motions in viscous fluids in the presence of body forces will help interpret experimental data, provide insight into the design of filler particles, and guide precision engineering of advanced composites. Nanocomposites with precisely aligned fillers will offer new opportunities for innovation in creating advanced biomaterial, optical, electromagnetic, and membrane technologies.