Polymeric Multilayer Films for Stabilization of Copper Nanostructures in Non-Enzymatic Glucose Sensing

Copper (Cu)-based electrodes have attracted significant attention for non-enzymatic glucose sensing owing to their high electrocatalytic activity and low cost. However, their practical application is often limited by surface degradation and signal instability during repeated electrochemical measurements. In this study, polymeric multilayer films were employed as an interfacial engineering platform to improve the stability and sensing performance of Cu-based electrodes. Polyelectrolyte multilayers containing carboxylic functional groups provided a tunable interfacial environment that facilitated the immobilization of Cu ions and the formation of stable Cu nanostructures. The resulting polymer-mediated architecture effectively maintained the electrochemically active surface while suppressing structural degradation during repeated electrochemical operation. As a result, the modified electrodes exhibited enhanced signal stability, reproducibility, and long-term durability compared with unmodified Cu electrodes. Electrochemical characterization confirmed that the polymer-modified electrodes maintained stable responses during repeated measurements and long-term storage tests. Furthermore, the multilayer films facilitated the formation of uniformly distributed Cu nanostructures, which contributed to improved sensing performance and operational stability. In addition, the modified electrodes demonstrated glucose sensing capability under artificial sweat conditions, suggesting their applicability to non-invasive glucose monitoring systems. These findings demonstrate that polymer-based interfacial engineering offers an effective strategy for stabilizing Cu nanostructures and developing reliable non-enzymatic glucose sensors for wearable and point-of-care diagnostic applications.