Development of High-Performance Self-Healing Pluggers for Harsh Environments: Molecular Dynamics Simulation and Material Design

To address the challenges of insufficient compatibility between crosslinking agents and main agents, as well as the shear failure of polymer gels under extreme conditions such as high-temperature (130°C) and high-salinity (20×104 mg·L-1), molecular dynamics simulations were employed to study the crosslinking effects of three agents ethyleneimine (EI), phenolic formaldehyde resin (PF), and N,N'-methylenebisacrylamide (MBA) on Acrylamide (AM) monomer and 2-acrylamido-2-methylpropane sulfonic acid (AMPS) copolymer systems. The stability of these systems under high temperature and salt conditions was also examined. By quantitatively evaluating electrostatic energy, van der Waals force energy, total potential energy, and total kinetic energy in each cross-linked network, it was found that PF-crosslinked gels exhibit superior stability. These gels demonstrated not only excellent thermal stability and salt resistance, but also remarkable resilience against adverse external conditions. To further enhance the material's potential, a dynamic crosslinking network based on carboxymethyl cellulose (CMC) and magnetic iron oxide (Fe3O4) nanoparticles was introduced. This was combined with a polymer formed by PF crosslinking PAA@PF, leading to the creation of a double-network gel system that significantly improved the self-healing capability. The results indicate that the developed composite plugging agent not only rapidly restores its physical and chemical properties after damage but also maintains high mechanical strength and toughness. This research provides new insights for developing a next-generation high-performance self-healing plugging agent and offers significant implications for expanding the applications of self-healing materials.