Strain sensing ability of GNP reinforced cementitious composites: The role of exfoliation and interlayer spacing
Strain sensing ability of GNP reinforced cementitious composites: The role of exfoliation and interlayer spacing
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DOI：
10.1016/j.conbuildmat.2023.131593
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发表时间：
2023-08
影响因子：
7.4
通讯作者：
Panagiotis A. Danoglidis;M. Konsta-Gdoutos
中科院分区：
文献类型：
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作者：
Panagiotis A. Danoglidis;M. Konsta-Gdoutos
在本研究中，研究了GNPs的剥离状态对GNP增强胶凝复合材料在弹性和后弹性变形阶段应变感知能力的影响。在渗透阈值以下，多层GNPs的有效剥落产生三层纳米材料。对于渗透以上的GNP体积分数，剥离的石墨烯层数与胶凝纳米复合材料的介电常数值之间存在直接相关性。电化学阻抗谱（EIS）测量表明，纳米复合材料的储能能力取决于石墨烯纳米片之间的层间距。压阻实验表明，压阻信号与后弹性阶段的应变水平无关。压介电常数结果表明，在弹性和后弹性阶段的加载-卸载循环中，介电常数的分数变化与应力和应变值之间存在良好的关系。压电常数与三层和多层GNPs的体积分数之间存在直接关系，这表明渗透阈值处的GNP含量对于最大化纳米复合材料的应变传感能力是最佳的。
In this study, the effect of the exfoliation state of GNPs on the strain sensing capacity of GNP reinforced cementitious composites at the elastic and post-elastic stages of deformation is demonstrated. Below percolation threshold, effective exfoliation of multi-layer GNPs results in tri-layer nanomaterials. For GNP volume fractions above percolation a direct correlation between the number of exfoliated graphene layers and permittivity values of the cementitious nanocomposites exists. Electrochemical Impedance Spectroscopy (EIS) measurements demonstrated that the nanocomposite’s electrical energy storage capacity depends on the interlayer spacing between graphene nanosheets. Piezoresistivity experiments showed that the piezoresistive signal is independent on the strain levels at the post-elastic stage. Piezopermittivity results revealed an excellent relationship between the fractional change in permittivity and stress and strain values during the loading–unloading cycles at both the elastic and post-elastic stages. A direct relationship between piezopermittivity and volume fraction of tri-layer and multi-layer GNPs is also observed suggesting that the GNP content at the percolation threshold is optimum for maximizing the strain sensing capacity of the nanocomposite.