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针对聚合物纳米复合材料次表面结构高分辨无损检测的需求,应用开尔文探针力显微镜(KPFM)对聚合物中导电填充物进行次表面纳米成像.首先,建立探针-纳米颗粒-基质体系的静电相互作用理论模型,分析聚合物中金属颗粒检测的成像机理;其次,通过有限元软件模拟并结合理论模型,系统研究针尖与样品间距、针尖半径等因素的影响;最后,制作聚合物和碳纳米管复合材料样品并进行基于KPFM的内部碳纳米管成像实验验证.结果表明:当针尖半径大约为1.5倍颗粒直径、间距较小时,成像效果较好;相较而言,探针锥角对成像结果影响不显著;KPFM对相对介电常数在3~10之间、颗粒直径越大、掩埋深度越小的内部纳米颗粒成像效果越好.
In order to meet the need of high-resolution non-destructive testing of subsurface structures of polymer nanocomposites, KELFM was used to image sub-surface nanostructures of conductive fillers in polymers.First, we established a probe-nanoparticle-matrix system Electrostatic interaction theory model to analyze the imaging mechanism of metal particles detection in polymer; secondly, through the simulation of finite element software combined with theoretical model, the influence of the distance between tip and sample, the radius of needle tip and so on; finally, the polymer and carbon The nanotube composite samples were verified by KPFM-based internal carbon nanotube imaging. The results show that the imaging effect is better when the tip radius is about 1.5 times the particle diameter and the spacing is small. In contrast, The effect of KPFM on the relative permittivity was between 3 and 10, the larger the particle diameter and the smaller the buried depth, the better the imaging effect was.