Molecular Insights into Cyclodextrin-Adamantane-Modified Copolymer Host-Guest Interactions.

Area of Science:

• Materials Science
• Chemical Engineering
• Petroleum Engineering

Background:

• Supramolecular polymer flooding shows promise for improving oil recovery in challenging low-permeability reservoirs.
• The molecular-level self-assembly mechanisms of these polymers are not fully understood, limiting optimization.
• Existing research methods have limitations in elucidating these complex assembly processes.

Purpose of the Study:

• To explore the formation mechanism of cyclodextrin and adamantane-modified supramolecular polymer hydrogels using molecular dynamics simulations.
• To elucidate the self-assembly mechanism of supramolecular polymers at the molecular level.
• To evaluate the effect of polymer concentration on the oil displacement index.

Main Methods:

• Molecular dynamics simulations were employed to investigate the self-assembly of supramolecular polymers.
• The study focused on cyclodextrin and adamantane-modified systems.
• The influence of varying polymer concentrations, including the critical association concentration (CAC), was analyzed.

Main Results:

• The self-assembly mechanism was characterized as a "node-rebar-cement" mode.
• Sodium ions (Na+) were found to form salt bridges, enhancing the formation of a compact 3D network structure.
• Increased polymer concentration, particularly above the CAC, significantly boosted association and promoted 3D network construction, leading to higher viscosity.

Conclusions:

• The study elucidates the molecular-scale assembly process and mechanism of supramolecular polymers.
• The findings provide a theoretical basis for designing and selecting functional units for supramolecular polymer assembly.
• This research offers insights into optimizing supramolecular polymer flooding for enhanced oil recovery in low-permeability reservoirs.