Assessing the Quality of Solvents and Dispersants for Low-Dimensional Materials Using the Corresponding Distances Method

Design Rules for Graphene and Carbon Nanotube Solvents and Dispersants

The constantly widening industrial applications of carbon-based nanomaterials puts into sharp perspective the lack of true solvents in which the materials spontaneously exfoliate to individual molecules. This work shows that the different geometry of graphene compared to that of carbon nanotubes can change the potency of a molecule to act as a solvent or dispersant. Through analysis of the structure/function relationships, we derive a number of design rules that will aid the identification of the best solvent or dispersant candidates.

Toward High-Throughput Computational Screening of Carbon Nanotube Solvents

We use the corresponding distances method (CDM) to computationally assess the quality of 10 experimentally tested carbon nanotube (CNT) solvents. The CDM produces accurate and high-resolution potential of mean force curves from a single simulation per solvent. The method's very high efficiency allows us to investigate an unprecedented number of solvents in one study. The simulation results indicate that none of the tested molecules are solvents in the thermodynamic sense; instead, they are dispersants preventing reaggregation of already dispersed CNTs. We find that the dispersion free energy barrier correlates very well with the experimentally measured performance of the dispersants; i.e., the simulations place the solvents in the correct performance order. Our analysis of the structure-function relationship rationalizes this order.