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

聚合物复合材料是具有两个或两个以上组分的材料体系，其中所产生的性能可以通过在加工过程中选择和放置单独的材料来定制。聚合物通常是较差的导热体，但当与导热纳米膜结合时，可产生具有理想导电性的聚合物复合材料，用于微电子封装、LED照明基板和太阳能电池板密封。多层共挤出是一种新型的制造技术，它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导热的关键因素，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应用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。多层共挤工艺与前驱体材料的适当设计相结合，可以生产出具有所需微观结构的纳米复合材料--形成纳米填料渗流网络，从而实现高效的热传导。然而，一些科学问题仍有待回答，如最佳的纳米填料特性，在低填充负荷下形成渗流网络的最有效方法，以及所需的热接触形态。该项目旨在通过覆盖整个材料研究循环的系统研究来填补知识空白，基于对多尺度热传输机制的基本了解来设计材料，调整制造工艺以实现所需的微观结构，并表征所产生的复合材料的导热系数以获得新的设计见解。这项合作研究验证了中心假设，即良好控制的多层共挤出工艺可以制备具有各向异性纳米薄膜之间直接接触形成的真正渗流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。该研究项目是一个探索多层纳米复合材料共挤出以生成所需微结构的团队与一个表征热传输特性以提供对材料设计和性能的见解的团队之间的合作。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。

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.