Multiwalled carbon nanotubes as hard templates to yield advanced geopolymer-based self-assembled nanostructured ceramics
Multiwalled carbon nanotubes as hard templates to yield advanced geopolymer-based self-assembled nanostructured ceramics
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DOI：
10.1016/j.mechrescom.2023.104216
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发表时间：
2023-12
影响因子：
2.4
通讯作者：
Yunzhi Xu;Haklae Lee;N. Buettner;A. Akono
中科院分区：
文献类型：
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作者：
Yunzhi Xu;Haklae Lee;N. Buettner;A. Akono
面对气候变化和极端天气，需要新型多功能建筑材料来促进弹性基础设施。纳米结构材料，如用碳基纳米材料增强的地聚合物，是实现这一目标的一种有希望的方法。近年来，一些研究研究了纳米材料对地聚合物复合材料抗压强度和断裂韧性等物理性能的影响。然而，对纳米材料对纳米尺度和微米尺度结构的影响的基本理解至今仍是难以捉摸的。我们的研究目标是了解多壁碳纳米管（MWCNT）如何帮助定制地聚合物的微观结构，从而产生结构多样的多功能纳米复合材料。我们合成了用50纳米厚的多壁碳纳米管增强的地聚合物纳米复合材料，其质量分数在0.1 wt%， 0.2 wt%和0.5 wt%之间。我们的主要发现是MWCNTs作为硬模板，通过自组装促进地聚合物的形成。地聚合物纳米颗粒沿着MWCNTs的壁生长。观察到晶粒尺寸的细化：增加0.5 wt%的MWCNTs含量可使晶粒尺寸减小54%。同样，傅里叶变换红外光谱结果和统计反褶积分析表明，增加MWCNTs的质量分数会导致地聚合物基体致密化。汞侵入孔隙度测定显示了纳米尺度的孔径分布：当MWCNTs的比例增加到0.5 wt%时，孔隙度降低了26%。由于这些纳米级的结构变化，mwcnts增强的地聚合物对长期变形的抵抗力更强，因为局部和宏观上的蠕变模量都增加了。在宏观水平上，当MWCNTs的含量增加到0.5 wt%时，观察到宏观对数蠕变模量增加42%。这些发现和支持的方法对于理解如何处理100 nm以下的物质是重要的。该研究还为设计具有定制微观结构和机械性能的弹性基础设施材料铺平了道路。
Novel multifunctional construction materials are needed to promote resilient infrastructure in the face of climate change and extreme weather. Nanostructured materials such as geopolymer reinforced with carbon-based nanomaterials are a promising way to reach that goal. In recent years, several studies have investigated the influence of nanomaterials on the physical properties of geopolymer composites such as compressive strength and fracture toughness. Yet, a fundamental understanding of the influence of nanomaterials on the nanoscale and micron-scale structure has been elusive so far. Our research objective is to understand how multiwalled carbon nanotubes (MWCNT) can help tailor the microstructure of geopolymers to yield architected multifunctional nanocomposites. We synthesized geopolymer nanocomposites reinforced with 50-nm thick multiwalled carbon nanotubes with mass fractions in the range of 0.1 wt%, 0.2 wt%, and 0.5 wt%. Our major finding is that MWCNTs act as hard templates that promote geopolymer formation via self-assembly. Geopolymer nanoparticle growth is observed along the walls of MWCNTs. A refinement in grain size is observed: increasing the fraction of MWCNTs by 0.5 wt% leads to a reduction in grain size by 54%. Similarly, increasing the mass fraction of MWCNTs leads to a densification of the geopolymer matrix as demonstrated by the Fourier transform infrared spectroscopy results and the statistical deconvolution analysis. Mercury intrusion porosimetry shows a nanoscale tailoring of the pore size distribution: a 26% decrease in porosity is observed as the fraction of MWCNTs is increased to 0.5 wt%. As a result of these nanoscale structural changes, a greater resistance to long-term deformation is observed for MWCNT-reinforced geopolymers, as the creep modulus increases both locally and macroscopically. At the macroscopic level, a 42% increase in the macroscopic logarithmic creep modulus is observed as the fraction of MWCNTs is increased to 0.5 wt%. These findings and the supporting methodology are important to understand how to manipulate matter below 100 nm. This research also paves the way for the design of resilient infrastructure materials with tailored microstructure and mechanical properties.