Fabrication Routes for Ionic Conducting Fiber Strain Sensors

Ionic conducting fiber strain sensors (ICFSs) are emerging as key components for wearable electronics, intelligent textiles, and soft robotics. By relying on ion transport instead of electron flow, ionic conducting materials are highly stretchable, mechanically compliant, and soft tissue compatible. Realizing these conductors in a fiber geometry ensures compatibility with established textile infrastructure, enabling seamless garment‐integrated sensing with straightforward scalability. Yet, despite rapid advances in materials and device concepts, the commercial viability of ICFSs is constrained by fiber fabrication routes. This review provides a fabrication‐centric analysis of ICFS technologies, systematically classifying reported devices into mold‐based, noncontinuously spun, and continuously spun fibers. For each category, the processing strategy and materials design are correlated with key performance metrics, including ionic conductivity, stretchability, gauge factor, durability, and environmental stability. Emphasis is placed on processing–property trade‐offs and on how parameters, such as spinning method, material structure, and cure chemistry, govern sensing performance and scalability. Finally, we highlight recent innovations that offer promising routes to reconcile high performance with continuous manufacturing. Based on these advances, we outline design guidelines to accelerate the transition of ICFSs from laboratory prototypes to scalable, textile‐integrated ionotronic technologies.