Monomer composition and HPMC-modified hydrogel electrolytes for electrochemical machining

Conductive hydrogels can serve as electrolytes in electrochemical machining (ECM), enabling localized material removal by confining electrochemical reactions. In this study, acrylic acid (AA) and 2-hydroxyethyl acrylate (HEA) were used to synthesize hydrogels with different monomer ratios, and their effects on ionic conductivity and ECM performance were investigated. Molecular dynamics simulations were performed to reveal the influence of anionic groups in AA on ionic transport. Hydroxypropyl methylcellulose (HPMC) was further introduced to optimize electrolyte performance. The results show that increasing HEA content enhances ionic conductivity and machining performance, whereas anionic groups in AA hinder ionic transport. Appropriate HPMC addition further improves electrolyte properties, leading to higher machining current and better surface quality. These findings clarify the roles of monomer composition and HPMC modification in hydrogel electrolytes, provide insight into ion transport mechanisms, and offer a practical strategy for designing high-performance hydrogel electrolytes for ECM.