Photoisomerizable molecule-grafted nanofluidic channels: strategies, mechanisms and applications

Abstract

The pursuit of artificial systems that emulate the precision and adaptability of biological nanochannels has culminated in the development of photoresponsive ionic nanofluidics. Incorporating photoisomerizable molecular switches (e.g., azobenzene, spiropyran, diarylethene) enables precise molecular-level control, enabling multi-dimensional regulation of pore size, surface charge, and wettability, offering unique advantages for smart ion-transport regulation. Despite substantial progress, the field still lacks a systematic framework connecting molecular modification strategies, transport regulatory mechanisms, and applications, which restricts the rational design of high-performance nanofluidic systems. This review addresses this critical gap by establishing a comprehensive, hierarchical molecule-strategy-mechanism-application framework based on recent developments. We systematically categorize and critically analyze three core modification approaches (i.e., direct grafting, mediator-assisted tethering, and host-guest embedding), elucidate hierarchical regulatory mechanism from single-property modulation to multi-dimensional synergistic control, and map these fundamental principles to advanced applications in energy conversion, ionic gating, and biomimetic devices. By integrating these principles and outlining a forward-looking research roadmap, this review provides a foundational blueprint for the rational design of next-generation, high-performance photonic nanofluidic channel devices with great potential across energy, environmental, and biomedical sectors.