Understanding the role of host-guest interactions in enhancing oil recovery through β‑cyclodextrin and adamantane modified copolymer

Abstract

Adamantane (ADA) and β-Cyclodextrin (β-CD) modified hydrolyzed polyacrylamide (MHPAM) polymers have been confirmed to have excellent performance in enhanced oil recovery (EOR). However, the molecular mechanism of the formation of three-dimensional polymer network structure has been not yet fully understood. In this work, the cross-linked mode of MHPAM polymers and their interaction information was investigated by molecular dynamics (MD) simulations and quantum chemical (QC) calculations. Results suggest that the ADA and β-CD molecules play a pivotal molecular recognition and binding role (like hormones and receptors, antigens and antibodies) in the process of host-guest interaction. The proposed mechanism of MHPAM cross-linking in the experiments was supplemented by our MD simulations. In addition, the strong electrostatic and van der Walls (vdW) component can be explained by the overlap of positive and negative ESP/vdW side. The viscosity of hydrolyzed polyacrylamide (HPAM) was increased via the modification of ADA and β-CD, which can be attributed to the hydrophobic associations of MHPAM. Based on our results, it will allow a more informed selection of these as polymers for use in enhanced oil recovery, enabling the properties of these polymers to be tailored to a particular application.