Department of Chemistry, Federal University of Paraná (UFPR), CP 19032, CEP 81531-980, Curitiba-PR, Brazil.
J Colloid Interface Sci. 2018 Nov 1;529:187-196. doi: 10.1016/j.jcis.2018.06.002. Epub 2018 Jun 4.
Dispersing carbon nanotubes is an easy and low-cost way to manipulate these solids and allows the preparation of more complex materials or devices, so it is fundamental for further uses that these dispersions have controlled properties and high colloidal stability. In this work we report the spontaneous electrical charge build-up in pristine multi-walled carbon nanotubes dispersed in common organic solvents such as chloroform and tetrahydrofuran and the achievement of dispersions stable for long periods without adding passivant agents or functional groups on nanotubes surface. Results from electrokinetics, homo- and heterocoagulation provided macroscopic evidences that carbon nanotubes acquire electric charges after dispersion in some organic liquids and we confirmed this process by measuring in situ Raman spectra of the nanotubes dispersions with higher surface electric potentials. We also show that the signal of electric potential of the dispersions can be predicted by the acid-base behaviour of the dispersing medium, corroborating previously reports for other dispersions of carbon nanomaterials.
分散碳纳米管是一种简单且低成本的操控这些固体的方法，并且允许制备更复杂的材料或器件，因此对于进一步的应用来说，这些分散体具有受控的性质和高胶体稳定性是至关重要的。在这项工作中，我们报告了在氯仿和四氢呋喃等常见有机溶剂中分散的原始多壁碳纳米管中自发的电荷积累，并且在不添加钝化剂或碳纳米管表面官能团的情况下，实现了长时间稳定的分散体。电泳、同-和异凝聚的结果提供了宏观证据，表明碳纳米管在一些有机溶剂中分散后会获得电荷，我们通过测量具有更高表面电势的碳纳米管分散体的原位拉曼光谱证实了这一过程。我们还表明，分散体的电势信号可以通过分散介质的酸碱行为来预测，这与以前关于其他碳纳米材料分散体的报告相符。
