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

EARLY概念探索性研究补助金（EAGER）提供资金，用于研究合成金属纳米线网络并将其嵌入相变材料的制造工艺的可行性，以提高相变储能系统的热性能。通常，相变材料的低导热率仍然是需要解决的关键限制因素，以实现大规模和稳健的能量存储系统，从而最大化可再生能源的效率。假设金属纳米线网络将促进热流的通过并产生相变材料的热导率的显著增强。处理步骤将包括在外加磁场下操纵磁性纳米线，然后进行热焊接工艺。首先，使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。第二，磁性纳米线将在静磁场下组装，以在所施加的场的方向上形成纳米线柱。最后，整个相变材料将被加热到高于焊料熔点的温度，以将纳米线永久地结合成网络。纳米线网络的结构形态将通过扫描电子显微镜表征。结合的网络将经受熔融/固化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。通过实验和分析相结合的方法，将研究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。如果成功，目前的研究将使一种新的相变材料，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。这项研究的结果将有助于在纳米结构复合材料的相变和热传输过程的基本理解。此外，对纳米线的相互作用和在磁场下形成结构网络的理解将有助于复合材料的纳米制造，这些复合材料可能用于医疗、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.