Tuning the Surface: Screen-Printed Flexible Porous Nanocomposite Electrodes with Programmable Electrochemical Performances for Wearable Platforms

Flexible electrodes fabricated through cost-effective thick-film strategies are important for developing electrochemical devices, such as sensors. Properly engineered nanocomposite electrodes can enhance the electrochemically active surface area, facilitate mass and charge transport, and allow for tailored surface chemistry and structure. Although great efforts have been devoted to developing porous nanocomposite electrodes, a facile method to achieve screen-printed porous nanocomposite electrodes in the form of flexible electrodes with tunable electrochemical performance has been overlooked. This article introduces a strategy for fabricating flexible porous electrodes using screen printing and electrochemical surface treatments, resulting in enhanced surface chemistry and electrochemical properties. By applying selective etching and anodization, the electrode's surface area increases by 214% compared to a nontreated electrode, enabling programmable sensitivity to specific molecules. The engineered electrode improves the hydroquinone-to-salicylic acid detection ratio from less than 1 to over 10, allowing selective detection of neutral and positively charged molecules while rendering the electrode inactive for negatively charged species. This flexible sensor can be integrated into a wearable glove for rapid analysis and has also been successfully implemented in a second-generation glucose biosensor. This approach holds significant potential for advancing surface electrochemistry, offering new possibilities for tailoring electrode surfaces for diverse analytical applications.