Collaborative Research: Multilayer Co-extrusion Processing of Thermally Conductive Polymer Nanocomposites

聚合物复合材料是具有两种或更多种组分的材料系统，其中所产生的性能可以通过在加工过程中选择和放置单个材料来定制。 聚合物通常是不良的热导体，但当与导热纳米填料组合时，可产生具有用于例如微电子封装、LED照明用基板和太阳能电池板密封件的应用的所需传导性的聚合物复合材料。多层共挤出是一种新型的制备技术，为制备具有理想结构和性能的聚合物复合材料提供了一条很有前途的途径。通过合理的材料设计，先进的制造和结构性能测量，该奖项确定了影响聚合物复合材料热传导的关键因素，并建立了一种聚合物加工方法，以制造具有重大社会经济影响的导热纳米复合材料。这种高度跨学科的研究为从高中到研究生水平的不同背景的学生提供了丰富的教育和培训机会。多层共挤出加工，当与前体材料的适当设计相结合时，可以产生具有所需微观结构的纳米复合材料-形成纳米填料渗透网络，以实现有效的热传导。然而，一些科学问题仍然有待回答，如最佳的纳米填料特性，最有效的方式来形成渗滤网络在低填料加载，以及所需的热接触形态。该项目旨在通过系统的研究填补知识空白，涵盖基于对多尺度热传输机制的基本理解设计材料的整个研究循环，调整制造工艺以实现所需的微观结构，并表征所得复合材料的热导率以获得新的设计见解。该合作研究测试了中心假设，即良好控制的多层共挤出加工可以生产具有由各向异性纳米填料之间的直接接触形成的真正渗滤网络的导热聚合物复合材料，以及具有低接触热阻的最佳网络形态。该研究项目是一个团队，探索多层纳米复合材料的共挤出，以产生所需的微观结构的团队和一个团队，表征热传输性能，提供深入了解材料的设计和性能的合作。该奖项反映了NSF的法定使命，并已被认为是值得通过评估使用基金会的智力价值和更广泛的影响审查标准的支持。

Polymer composites are materials systems with two or more components where the resulting properties can be tailored by the choice and placement of the individual materials during processing. Polymers are normally poor thermal conductors, but when combined with thermally conductive nanofillers, can result in a polymer composite with desirable conductivity for applications such as microelectronic packaging, substrates for LED-lighting, and solar panel seals. Multilayer co-extrusion, a novel manufacturing technology, provides a promising route to fabricate polymer composites of desirable architecture and properties. Through rational materials design, advanced manufacturing, and structure-property measurements, this award identifies key factors that affect heat conduction in polymer composites and establishes a polymer processing approach to manufacture thermally conductive nanocomposites for applications with significant socio-economic impact. This highly interdisciplinary research provides rich education and training opportunities for students of diverse backgrounds from high-school to graduate level. Multilayer co-extrusion processing, when combined with proper design of the precursor materials, could produce nanocomposites with desired microstructure - forming a nanofiller percolation network to enable efficient heat conduction. However, several scientific questions remain to be answered, such as optimal nanofiller characteristics, the most effective way to form percolation networks at a low filler loading, and the desired thermal contact morphology. This project aims to fill the knowledge gap through systematic studies covering the entire research loop of designing materials based on fundamental understanding of multiscale thermal transport mechanisms, tuning the manufacturing processes to achieve desired microstructures, and characterizing the thermal conductivity of the resulting composites to obtain new design insights. The collaborative study tests the central hypothesis that well-controlled multilayer co-extrusion processing can produce thermally conductive polymer composites with true percolation networks formed by direct contacts between anisotropic nanofillers and an optimal network morphology with low contact thermal resistance. This research project is a collaboration between a team that explores co-extrusion of multilayer nanocomposites to generate the desired microstructures and a team that characterizes thermal transport properties to provide insights into materials design and performance.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.