Micro- and nanostructured liquid–solid interfaces: recent developments and applications

Abstract Micro and nanostructured liquid–solid (LS) interfaces have emerged as a crucial platform for advancing self-powered sensing and energy harvesting technologies, particularly in liquid–solid triboelectric nanogenerators (LS-TENGs). Compared with conventional solid–solid systems, LS interfaces offer reduced mechanical wear, improved durability, and unique interfacial charge dynamics. This review provides a comprehensive overview of recent progress in understanding LS interfacial charge-generation mechanisms and in engineering micro and nanostructured surfaces to enhance triboelectric performance. The transition from classical electric double layer (EDL) theory to Wang’s hybrid EDL model is discussed to clarify the dominant role of direct electron transfer during liquid–solid contact electrification. The effects of nonpolar oils, superlubric liquid layers, and asymmetric electrolytes on interfacial charge regulation are systematically summarized. Furthermore, recent advances in microstructured LS interfaces-including bioinspired surfaces, tip-array architectures, photoresponsive microstructures, and wettability-engineered designs are reviewed in terms of their influence on contact dynamics and charge stability. At the nanoscale, electrospun nanofibers, nanoparticle-decorated polymers, nanowires, metallic nanotube arrays, and laser-induced graphene are highlighted as effective strategies to amplify surface area, local electric fields, and multifunctionality. Finally, emerging applications in energy harvesting, chemical, and biological sensing are discussed. This review elucidates structure-interface-function relationships at LS interfaces and provides design guidelines for next-generation self-powered sensing and energy-harvesting platforms.