Molecular mechanisms of asphaltene dispersion by acrylamide-based polymers: A combined study of molecular dynamics simulations, geometric analysis, and density functional theory calculations

• Multiscale investigation of polyacrylamide-asphaltene interactions through integrated molecular dynamics and density functional theory calculations • Development of a novel geometric analysis method for quantitative assessment of asphaltene aggregation states • Identification of electrostatic interactions as the dominant mechanism in asphaltene dispersion • Demonstration of enhanced molecular reactivity through chlorine modification, evidenced by reduced HOMO-LUMO energy gaps (5.18 eV vs. 4.94 eV) • Significant improvement in asphaltene dispersion efficiency (94.49%) achieved through strategic chlorine functionalization of polyacrylamide derivatives Asphaltene deposition during petroleum production presents persistent flow assurance challenges, necessitating advanced chemical solutions. This study elucidates the molecular mechanisms underlying asphaltene dispersion using acrylamide-based polymers through an integrated computational approach. Molecular dynamics simulations, geometric analysis, and density functional theory calculations were employed to investigate polymer-asphaltene interactions at multiple scales. A novel centroid triangle analysis method was developed to quantify dispersion efficiency, revealing that polyacrylamide (PAM) and chlorinated polyacrylamide (PAM-Cl) enhance asphaltene dispersion by 67.14% and 94.49%, respectively, at 298 K. Electronic structure analysis demonstrates that chlorine modification in acrylamide derivatives significantly alters molecular charge distribution, enhancing electrostatic interactions while reducing van der Waals forces. Quantum chemical calculations confirm that chloroacrylamide exhibits superior molecular activity, evidenced by a reduced HOMO-LUMO gap (5.18 eV vs. 4.94 eV) and increased electronegativity (3.249 vs. 2.673) compared to unmodified acrylamide. The findings establish electrostatic interactions as the dominant mechanism in asphaltene dispersion, providing fundamental insights for rational design of next-generation asphaltene inhibitors. This work advances our understanding of structure-activity relationships in asphaltene control chemicals, offering practical solutions for mitigating deposition-related challenges in petroleum operations.