Molecular Dynamics Study of the Dispersion Stability and Fluidity of Porous Liquids with Different Canopy Structures

Abstract

Porous liquids (PLs) as a new class of materials have broad application prospects in many areas such as gas separation and storage, air separation, and homogeneous catalysis. Here, molecular dynamics simulations were used to advance the understanding of PLs with different canopy structures. PLs composed of hollow SiO2 molecules, which were functionalized with polymer chains containing coronas and canopies to make them liquid at accessible temperatures, were quite different from pure SiO2 nanoparticles. It was found that linear and long canopy structures were better for dispersion of PLs, which was mainly due to the steric hindrance effect instead of electrostatic (charge) repulsion. In addition, simulation results demonstrated that PLs with long and linear polymer chains tended to have smaller relative entanglement depth, which means lower viscosity and better fluidity. Moreover, to keep intrinsic pores empty, PLs should possess long and linear canopies.