Electrohydrodynamic Printing of Functional Inks for Flexible Electronics: Mechanisms, Materials, and Applications

ABSTRACT Electrohydrodynamic (EHD) jet printing has emerged as a powerful additive micro/nanofabrication technique for next‐generation flexible electronics, offering exceptional resolution, compatibility with diverse inks, and patterning capabilities on unconventional substrates. This review presents a comprehensive overview of the fundamental principles, printable material systems, including conductive, semiconductive, insulating, and biofunctional inks—and recent innovations in process control tailored for flexible substrates. Critical challenges such as jet instability, poor adhesion on insulating surfaces, and multi‐material integration are addressed through advanced strategies such as pulse‐modulated electric fields, plasma‐induced virtual electrodes, coaxial sheath flow confinement, and ring‐electrode field shaping. Furthermore, we summarize recent advances in the scalable fabrication of flexible devices such as organic field‐effect transistors (OFETs), bioelectronic sensors, and stretchable circuits, highlighting how EHD printing uniquely enables high‐resolution patterning, structural anisotropy, and multi‐scale integration. Finally, we discuss the roadmap and technological bottlenecks for translating EHD printing from laboratory demonstrations to real‐world applications in wearable systems, soft robotics, and biointerfaces.