EAGER: Magnetically Assembling and Soldering of Nanoscale Metal Network into Phase Change Material

这项探索性研究（EAGER）的早期概念拨款为研究一种制造工艺的可行性提供了资金，该工艺将金属纳米线网络合成并嵌入相变材料中，以提高相变储能系统的热性能。总的来说，相变材料的低导热系数仍然是一个关键的限制因素，需要解决，以实现大规模和强大的储能系统，以最大限度地提高可再生能源的效率。假设金属纳米线网络将促进热流的传递，并显著提高相变材料的导热性。加工步骤将包括在外加磁场下操纵磁性纳米线，然后是热焊接过程。首先，采用基于模板的电沉积方法制造具有磁芯（镍或钴）和两个焊接头的多段磁性纳米线。其次，将磁性纳米线在静磁场下组装，沿外加磁场方向形成纳米线柱。最后，整个相变材料将被加热到高于焊料熔点的温度，以永久地将纳米线连接成一个网络。纳米线网络的结构形态将通过扫描电子显微镜进行表征。结合网络将经受熔化/凝固循环，以确定纳米结构的稳定性和机械完整性。纳米线网络的热传输能力将通过电导测量来评估。网络结构与工艺参数之间的关系，如磁场强度，纳米线负载，加热和焊接温度，以及材料的热物理性能将通过实验和分析相结合的方法进行研究。如果成功，目前的研究将使一种新的相变材料成为可能，这将影响可再生能源存储行业和许多不同的应用，如紧凑型热交换器、电子冷却和用于热保护的智能纺织品。本研究的结果将有助于对纳米结构复合材料的相变和热输运过程的基本理解。此外，了解纳米线的相互作用和磁场下结构网络的形成将有助于复合材料的纳米制造，这些材料可能用于医疗、汽车、食品加工和半导体包装等行业。

This EArly-concept Grant for Exploratory Research (EAGER) grant provides funding to study the feasibility of a manufacturing process to synthesize and embed a metallic nanowire network into phase change materials to enhance thermal performance of phase-change energy storage systems. In general, the low thermal conductivity of phase change materials is still a critical limiting factor that needs to be addressed to achieve large scale and robust energy storage systems to maximize the efficiency of renewable energy sources. The hypothesis is that the metal nanowire network will facilitate the pass for heat flow and yield significant enhancement in thermal conductivity of phase change material. The processing steps will consist of manipulating magnetic nanowires under an applied magnetic field followed by a thermal soldering process. First, multi-segmented magnetic nanowires with a magnetic core (Nickel or Cobalt) and two soldering heads will be fabricated using a template based electrodeposition method. Second, the magnetic nanowires will be assembled under a static magnetic field to form nanowire columns in the direction of the applied field. Finally, the entire phase change material will be heated to a temperature above the melting point of the solders to permanently bond nanowires into a network. The structural morphology of the nanowire network will be characterized by scanning electron microscopy. The bonded network will be subjected to melting/solidification cycles to determine the stability and mechanical integrity of the nanostructure. The heat transport capability of the nanowire network will be evaluated through electric conductance measurements. The relationships between network structure and processing parameters such as magnetic field strength, nanowire loading, heating and soldering temperatures, and material thermophysical properties will be investigated through a combined experimental and analytical approach.If successful, the present research will enable a new kind of phase change material, which will impact the renewable energy storage industry and a number of diverse applications such as compact heat exchangers, electronic cooling, and smart textiles for thermal protection. The outcome of this research will contribute to a fundamental understanding of phase change and thermal transport processes in nanostructured composite materials. In addition, the understanding of the interactions of nanowires and formation of structural networks under a magnetic field will contribute to the nanomanufacturing of composite materials that could potentially be used in industries such as medical, automobile, food processing and semiconductor packaging.