EAGER: The Verge of Percolation in Nanoparticle Networks

这项早期概念探索性研究资助（EAGER）为评估生产具有可控线性纳米填料浓度分布的分级纳米复合材料的可行性提供了资金。实验研究的重点是一种定制加工技术，该技术使用双斜流量泵、静态混合器和快速固化来制造具有恒定梯度增强的纳米填充聚合物复合材料。浓度分布将通过固化前从复合前驱体中提取的样品的光吸收来测量。固化后，电导率曲线将使用四点探针逐点测试。理想的纳米填料是原始的石墨烯，这种纳米材料因其出色的输运特性组合而备受赞誉。要探索的聚合物基质包括聚二甲基硅氧烷和环氧树脂。由于石墨烯片具有导电性，因此假设轴向电导率曲线模拟了渗透结垢规律，因此梯度复合材料可以用于研究渗透阈值和临界结垢指数如何受到不同分散质量、纳米填料几何形状和纳米填料尺寸作为超声函数的影响。如果成功，该项目将提供纳米级的洞察力（渗透网络架构），并有助于先进的材料功能（在航空航天和能源工业的传感应用中）。通过这种技术生产的复合材料将允许高精度、高重复性的纳米填料在聚合物基质中的渗透比较研究。这种复合材料可以立即应用于一系列工程需求，特别是在下一代压阻智能材料中。受这项探索性工作影响的广泛科学界包括那些对纳米材料剥离和分散、复合材料制造、渗透理论和纳米材料电接触和网络感兴趣的科学界。

This EArly-concept Grant for Exploratory Research (EAGER) award provides funding to evaluate the feasibility of producing graded nanocomposites with controlled linear nanofiller concentration profiles. Experimental research aims focus on a custom processing technique where dual ramped-flowrate pumps, a static mixer, and rapid curing are used to create nanofiller-loaded polymer composites with a constant gradient in reinforcement. The concentration profile will be measured by light absorbance in samples taken from the composite precursor prior to curing. The conductivity profile will be tested pointwise using a four-point probe after curing. The desired nanofiller is pristine graphene, a nanomaterial prized for its outstanding combination of transport properties. Polymer matrices to be explored include Polydimethylsiloxane and epoxy. Because the graphene sheets are conductive, it is hypothesized that the axial conductivity profile mimics percolation scaling laws such that gradient composites may be used to investigate how percolation threshold and critical scaling exponent are affected by varying dispersion quality, nanofiller geometry, and nanofiller size as a function of sonication. If successful, this project will provide nanoscale insight (into percolating network architecture) and contribute to advanced material functionality (in sensing applications in the aerospace and energy industry). The composites produced by this technique will allow for high-accuracy, high-repeatability comparative studies of nanofiller percolation within polymer matrices. Such composites have immediate application to a range of engineering needs, particularly in next-generation piezoresistive smart materials. Broad scientific communities affected by this exploratory work include those interested in nanomaterial exfoliation and dispersion, composite manufacture, percolation theory, and nanomaterial electrical contacts and networks.