Microscopic understanding of the supramolecular interaction in enhanced oil recovery

Abstract

The researchers found that supramolecular polymers have great application potential in improving oil recovery in medium and high permeability reservoirs, especially supramolecular polymers based on host–guest interaction. This study employed quantum chemical calculations and molecular dynamics simulations to investigate the interaction between adamantane and cyclodextrin molecular monomers, as well as the self-assembly mechanism of their modified carboxymethylcellulose in an aqueous solution. The study found that the interaction between adamantane and cyclodextrin molecular monomers is obvious, and the interaction is mainly van der Waals interaction rather than electrostatic interaction. The simulation results for molecular dynamics indicate that modified carboxymethylcellulose polymers follow an assembly mechanism summarized as “node-reinforcement-cement”. In this mechanism, modified molecules interact closely with each other, forming a “node”. The supramolecular polymer then unfolds around the node, creating a “reinforcement bar”. Finally, the addition of water molecules acts as “cement” to form a supramolecular hydrogel. Our research reveals the mechanism of supramolecular self-assembly at the molecular level, which provides a theoretical basis for the next step in the design of new supramolecular polymers.