Comparative study of ionic liquid and polymerized ionic liquid interfaces: from localized interactions to cooperative binding in gallic acid sensing

IL-to-PIL transformation enabled distinct interfacial reconstruction in HsGY/MWCNTs composites. • Polymerization reorganizes PIL interfaces into cooperative multivalent ionic networks. • The PIL5@HsGY/MWCNTs sensor achieved sensitive and stable GA detection. To investigate the distinct interfacial roles of ionic liquids (ILs) and polymerized ionic liquids (PILs), IL- and PIL-functionalized hydrogen-substituted graphyne/multi-walled carbon nanotube (HsGY/MWCNTs) composite electrodes were constructed, with gallic acid (GA) employed as a model analyte and density functional theory (DFT) calculations used to elucidate interfacial interaction mechanisms. After IL functionalization and in situ polymerization, distinct surface morphologies and electrochemical characteristics were observed for the resulting composite electrodes, while different electrochemical responses toward GA were obtained for the IL- and PIL-based composites, highlighting the influence of the modified sensing layers on electrode performance. Under optimized conditions (pH 3.0 and 150 s accumulation), the PIL5@HsGY/MWCNTs/GCE exhibited a linear range of 0.3–10 μM and a detection limit of 0.077 μM. Acceptable repeatability, reproducibility, and stability were achieved by the sensor, and its anti-interference performance was preliminarily evaluated through interference tests. Satisfactory recoveries of 97.68–103.33% were obtained in strawberry and green tea beverage samples. Overall, the distinct interfacial mechanisms of IL and PIL functionalization were elucidated, providing valuable insights for the rational design of high-performance electrochemical sensor interfaces. Download: Download high-res image (145KB) Download: Download full-size image