Solvent‐mediated self‐assembly and hydrogen bonding in neutral alginate: a molecular dynamics study

Hydrogen bonding plays a pivotal yet often overlooked role in shaping the structure and dynamics of alginate‐based materials. In this study, we use molecular dynamics (MD) simulations to investigate how hydration and solvent environment influence the organization of neutral alginate at the molecular and mesoscale levels. Starting from short isolated chains and progressing toward periodic and entangled systems, we systematically vary water content and examine structural responses using radial and minimal distance distribution functions, as well as geometric analysis based on Alpha Shapes. We find that hydration transforms the polymer matrix from compact, rigid bundles into layered and porous nanostructures, with water acting not merely as a plasticizer but as an active mediator of hydrogen bonding. Even small amounts of water accelerate supramolecular aggregation and promote internal flexibility. At higher hydration, polymer–polymer contacts become more diffuse yet remain structurally coherent. A comparison with ethanol reveals solvent‐specific effects on porosity and tortuosity, while the functional surface composition remains robust across all conditions, closely reflecting the molecular stoichiometry of the polymer. These results provide a detailed molecular‐level understanding of solvent‐mediated self‐assembly in alginate and offer general design principles for soft, bioinspired materials where hydrogen bonding is the key structural motif.