Molecular-level studying on the dispersion mechanism of surfactants in coal-water slurry by molecular dynamics...

This study elucidates the microscopic dispersion mechanism of surfactants in coal-water slurry through molecular dynamics (MD) simulations. The research systematically investigates the adsorption behavior and regulatory roles of nonionic, cationic, amphoteric, and anionic surfactants at the coal-water interface. Specifically, nonionic surfactants reduce interfacial tension via hydrogen bonding and hydrophobic interactions; cationic surfactants enhance dispersion through charge neutralization; while polycarboxylic anionic surfactants improve the rheological properties of the slurry by means of electrostatic repulsion and steric hindrance. By integrating the Materials Studio platform, this study systematically analyzed key simulation methodologies, including force field selection, adsorption energy calculation, and adsorption configuration determination. The underlying microscopic mechanisms were further validated through experimental techniques such as atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). The research critically examined the current limitations of molecular dynamics simulations, such as model simplification and high computational costs, and highlighted the promising applications of machine learning in areas including force field optimization, conformational sampling, and performance prediction. Furthermore, a strategic approach was proposed that combines multi-scale simulation methods (e.g., dissipative particle dynamics, DPD) with high-precision force fields to improve both simulation efficiency and predictive accuracy. This study not only elucidates the molecular-level mechanisms by which surfactants regulate the dispersion and stability of coal-water slurry, but also establishes a robust theoretical foundation and technical framework for the rational design and practical application of high-performance, eco-friendly coal-water slurry dispersants.