Advances in multimodal electrohydrodynamic printing for high-resolution sensor fabrication: mechanisms, materials, and applications.

With the rapid development of micro-electromechanical systems (MEMS) and the manufacturing industry, the trends toward sensor intelligence, miniaturization, and flexibility have attracted significant attention while posing higher demands for high-resolution patterning and large-scale production. However, traditional manufacturing technologies exhibit significant limitations in achieving high resolution and multifunctional integration. Electrohydrodynamic (EHD) printing technology, which harnesses the synergistic effects of electric fields and fluid dynamics, enables precise control over the formation and deposition of micro-nanometer jets. It offers ultra-high resolution, broad material compatibility, and controllable three-dimensional structural formation, providing innovative solutions for the intelligent, miniature, and flexible integration of sensors. This paper systematically reviews the mechanisms and applications of three EHD printing modes-EHD jet printing, electrospray and electrospinning. It further describes the progress in the printing of materials suitable for EHD printing, including metal nanoparticles, conductive polymers, carbon-based materials, and piezoelectric ceramics. Additionally, the application progress of gas, temperature, humidity, piezoelectric and strain sensors based on the three EHD printing modes is summarized, highlighting their advantages in sensitivity, response speed, and environmental adaptability. The paper also explores the challenges of low efficiency and future development directions, such as multi-nozzle coordination, nozzle structure optimization, roll-to-roll integration manufacturing, and intelligent process control. Finally, a brief summary and the outlook for future research effort are presented.