Advances in Molecular Dynamics Simulations for Hydrogels and Nanocomposite-Reinforced Hydrogels: Multiscale Simulation Strategies and Future Directions.

Hydrogels and nanocomposite-enhanced hydrogels, owing to their high-water content, excellent biocompatibility, and mechanical flexibility, have demonstrated broad application prospects in tissue engineering, drug delivery, and flexible electronics. With the continuous advancement of computational power, molecular dynamics (MD) simulations have increasingly become an important tool for characterizing nanocomposite materials and hydrogel systems. This approach enables the capture of structural evolution at the atomic/molecular scale and provides mechanistic insights into deformation behaviors and interaction mechanisms under external stimuli such as mechanical force, temperature, and electric fields. This review is organized around the central framework of "structural construction-interfacial regulation-responsive behavior-dynamic evolution", and systematically summarizes the recent progress in the application of molecular dynamics and multiscale simulation methods to hydrogels and nanocomposite hydrogels. The systems discussed mainly include synthetic polymer-based hydrogels, natural polymer-based hydrogels, peptide/protein-based hydrogels, and nanocomposite hydrogels. Particular emphasis is placed on modeling strategies and force-field selection principles for describing atomic interactions in various nanocomposite hydrogel systems. In addition, the important applications of multiscale simulation strategies in elucidating the interfacial behavior of hydrogels and the mechanisms underlying their dynamic responses under nonequilibrium conditions are also discussed. Finally, future development trends are outlined, including multiscale coupled simulations, closed-loop correction between experiments and simulations, and data-driven modeling strategies for the precise design and performance prediction of complex hydrogel systems.