Abstract The reinforcement of composites by carbon-nanotubes (CNTs) is typically limited by agglomeration and non-uniform dispersion. Thus, achieving a nanocomposite with high density of reinforcement material is a tough challenge. In this work, rather than mixing CNTs in a matrix, we first construct a dense CNT-network scaffold, and then impregnate it by the matrix to obtain a composite. To that end, we explore an evaporation-driven self-assembly approach to form 3D CNT scaffolds on quartz fibers, which combines high CNT density and nanoscale pore size with a straightforward, efficient process. The scaffold is thicker than the fiber by more than an order of magnitude, with a typical pore size of 70nm and porosity of 60%. The strength of a scaffold-reinforced composite is evaluated by a fragmentation test. μCT 3D-reconstruction of the fragmented scaffold reveals that the matrix-impregnated scaffold creates a multiscale structure that under load behaves much like a fibrous composite. The fragmentation results are analyzed by a mechanical model, demonstrating a scaffold-composite strength of ∼200MPa. The improved strength and relatively high CNT volume fraction (∼20%), along with the capability of tuning the scaffold thickness and density, make the proposed structure a promising prospect for composite reinforcement, as well as for diverse nanoscale applications.

中文翻译：

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用于复合增强材料的蒸发驱动 3D CNT 脚手架

摘要 碳纳米管 (CNT) 对复合材料的增强通常受到团聚和非均匀分散的限制。因此，获得具有高密度增强材料的纳米复合材料是一项艰巨的挑战。在这项工作中，我们不是在基质中混合碳纳米管，而是首先构建一个致密的碳纳米管网络支架，然后将其浸入基质中以获得复合材料。为此，我们探索了一种蒸发驱动的自组装方法，以在石英纤维上形成 3D CNT 支架，该方法将高 CNT 密度和纳米级孔径与简单、高效的过程相结合。支架比纤维厚一个数量级以上，典型孔径为 70nm，孔隙率为 60%。脚手架增强复合材料的强度通过破碎试验进行评估。碎片支架的 μCT 3D 重建显示，基质浸渍的支架创建了多尺度结构，在负载下表现得非常像纤维复合材料。破碎结果通过力学模型进行分析，表明支架复合材料强度约为 200 MPa。提高的强度和相对较高的 CNT 体积分数（~20%），以及调节支架厚度和密度的能力，使所提出的结构成为复合增强材料以及各种纳米级应用的广阔前景。