Mechanisms of Single-Walled Carbon Nanotube Network Formation and Its Configuration in Polymer-Based Nanocomposites
Mechanisms of Single-Walled Carbon Nanotube Network Formation and Its Configuration in Polymer-Based Nanocomposites
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DOI：
10.1021/acs.macromol.0c02763
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发表时间：
2021-03-19
期刊：
影响因子：
5.5
通讯作者：
Perse, Lidija Slemenik
中科院分区：
文献类型：
--
作者：
Oseli, Alen;Vesel, Alenka;Perse, Lidija Slemenik
碳纳米管聚合物基纳米复合材料的增强和导电性能取决于所建立的网络及其构型。在这项研究中，我们利用单壁碳纳米管（SWCNTs）在低密度和高密度聚乙烯矩阵的这种网络形成的基本机制报告。通过Doi-Edwards理论对机理进行了理论评估，并通过等离子体蚀刻结合电子显微镜以及流变流动测试进行了实验证实。结果表明，所建立的网络由SWCNT束构成，其在临界体积分数Phi（v，crit）下几何缠结（棒的数量：β近似于30）。在Phi（v，crit）以下，束表现为单独的单元，并且可以在流动方向上对齐。在Phi（v，crit）以上，束的旋转受到相邻单元的约束，导致随机网络配置。此外，该理论成功地解释了作为布朗实体的单壁碳纳米管束行为，并预测通过减少热和流体动力学驱动的扩散形成网络，这可以在生产过程中进行操纵，以增强这种材料的增强/导电功能。
The reinforcing and conductive performance of carbon nanotube polymer-based nanocomposites depends on the established network and its configuration. Within this study, we report on the underlying mechanisms of such network formation utilizing single-walled carbon nanotubes (SWCNTs) in low- and high-density polyethylene matrices. Mechanisms were theoretically evaluated through Doi-Edwards theory and experimentally confirmed through plasma etching coupled with electron microscopy as well as rheological flow tests. Results showed that the established network is constructed from SWCNT bundles, which geometrically entangle at a critical volume fraction Phi(v, crit) (number of rods: beta approximate to 30). Below Phi(v,crit), the bundles behave as individual units and may align in the flow direction. Above Phi(v,crit), the rotation of bundles is constrained by neighboring units, leading to a random network configuration. Moreover, the theory successfully explains SWCNT bundle behavior as a Brownian entity and predicts network formation through diminishing thermo- and hydro-dynamically driven diffusion, which can be manipulated during the production to enhance reinforcing/conductive functionality of such materials.