Aggregation Kinetics and Stability Mechanisms of Pristine and Oxidized Nanocarbons in Polar Solvents

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• 作者：Nima Sefidmooye Azar ; Mahdi Pourfath
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：August 4, 2016
• 年：2016
• 卷：120
• 期：30
• 页码：16804-16814
• 全文大小：933K
• 年卷期：0
• ISSN：1932-7455

文摘

Owing to their high propensity for bundling and aggregation, effective and stable dispersion of nanocarbons in polar solvents is of key significance in the preparation of carbon nanotube (CNT) and graphene nanosheet (GNS)-based devices and nanocomposites. Previous studies have shown that oxidation of CNT side walls and GNS surfaces ameliorates their stability in polar solvents. In this study, large-scale all-atom molecular dynamics simulations were employed to shed light on the stability mechanisms of nanocarbons in polar solvents and explicate the role of surface modification in their dispersibility enhancement. The concepts of potential of mean force (PMF) and translational kinetic energy (TKE) were utilized for this purpose. Our studies disclosed the physical facts lying behind the remarkably higher stability of modified nanocarbons in polar solvents compared to the pristine ones. First, the oxidized nanocarbons are intrinsically much less motivated to form aggregates, and second, the solvent-induced repulsion is much stronger in the case of oxidized nanocarbons. It was also revealed that among the various solvents considered here, N-methyl-2-pyrrolidone (NMP) provides the most stable solutions for the both pristine and oxidized nanocarbons, followed by dimethyl sulfoxide (DMSO), dimethylformamide (DMF), 1,2-dichlorobenzene (ODCB), and tetrahydrofuran (THF). This work provides a comprehensive understanding of the nanocarbons stability that will facilitate the handling of their aggregation issue.