Semi‐Interpenetrated Poly( N,N ‐Diethylacrylamide)/Poly(Methyl Vinyl Ether)/Graphene‐Oxide Composite Hydrogel: Synthesis, Characterization, and Swelling Behavior

ABSTRACT The study introduces a novel class of thermo‐responsive semi‐interpenetrated hydrogel networks based on poly ( N,N ‐diethylacrylamide) (PDEA) and poly (methyl vinyl ether) (PMVE), along with their graphene oxide (GO)‐based composites. Poly ( N,N ‐diethylacrylamide) was synthesized via free‐radical polymerization using varying crosslinker concentrations. The swelling behavior of the hydrogels and composites was systematically investigated as a function of temperature and pH. Both pure and GO‐incorporated hydrogels exhibited lower critical solution temperature (LCST)‐type thermal responsiveness, with transition temperatures in the range of 40°C–45°C. Incorporation of GO enhanced swelling capacity, thermal stability, and responsiveness due to additional hydrophilic sites and physical crosslinking effects. Swelling studies under acidic (pH 2), neutral (pH 7), and mildly alkaline (pH 10) conditions demonstrated that GO‐based composites consistently outperformed pure hydrogels, reaching maximum swelling at alkaline pH due to deprotonation‐induced electrostatic repulsion. The point of zero charge (pHpzc) for both systems was determined to be approximately 7.9, indicating predominantly basic surface characteristics. Structural analyses using FTIR confirmed successful polymerization and GO incorporation, while SEM imaging revealed uniform, crosslinked morphologies. The results highlight that GO incorporation significantly improves hydrogel performance, making these composites promising candidates for smart adsorption, controlled release, and efficient treatment of dye‐contaminated wastewater.