Unraveling Polymer-Water Interaction: Ab Initio Insights into Neutral Polymer Hydration

The prevention of ice formation and accumulation on solid surfaces presents a significant challenge across various engineering and technological domains. Recent advancements in aqueous self-lubricating coatings have garnered considerable attention due to their promising anti-icing performance. These coatings effectively reduce ice formation, offering potential solutions for various applications. Our study focuses on the hydration of neutral polymers, providing significant insights into water-polymer interactions at the molecular level. We employ density functional theory (DFT) to investigate the hydration behavior of four representative neutral polymers: poly(ethylene glycol) (PEG), linear polyglycerol (linPG), polyvinylpyrrolidone (PVP), and polyethylene (PE), each selected for their distinct properties and hydrophilicity/hydrophobicity. A comprehensive bond analysis using crystal orbital hamilton populations (COHP) reveals strong hydrogen bonding between the water molecules and the oxygen atoms of the hydroxyl group in hydrophilic polymers. Polymers with diverse functional groups exhibit pronounced interactions with water molecules, particularly hydrophilic moieties, which show strong affinity toward water molecules. In contrast, polymers lacking hydrophilic functionalities exhibit significantly reduced interactions with water molecules. This bonding characterization is further supported by electron partial density of states (PDOS), Bader charge analysis, and energy calculations, which collectively elucidate the physicochemical nature of the water-polymer interactions. A detailed understanding of molecular-level interactions opens new avenues for tailoring polymer design and hydration behaviors to achieve enhanced anti-icing performance.