CO₂ Viscosification by Functional Molecules from Mesoscale Simulations

Abstract

The viscosity increase of carbon dioxide by copolymers is predicted using dissipative particle dynamics simulations, as a function of polymer concentration. Three types of direct viscosifying polymers are simulated: a fluorinated acrylate polymerized with styrene and two nonfluorinated copolymers. The latter are the hydrocarbon-based poly(1-decene), which is branched, and the linear poly(vinyl ethyl ether). These polymers associate differently in CO2 because of their different molecular and chemical characteristics. The effect of different association mechanisms in increasing the viscosity of CO2 is investigated in detail. It is found that intermolecular interactions and branched structure contribute to CO2 thickening. In the fluorinated copolymer, intermolecular π-stacking interactions significantly affect CO2 viscosification. These are the first simulations of the viscosity of CO2 thickeners; our simulations agree with recent experimental data, providing insights into the thickening mechanisms at play of each molecule. This work sets the stage for the molecular engineering of new CO2 viscosifiers.