Single‐Fiber Design for Higher Performance Artificial Muscles

ABSTRACT Artificial muscles are essential components in the advancement of next‐generation soft robotics, biomedical devices, and adaptive wearables. While conventional fiber‐based actuators often rely on multi‐material assemblies and complex interfacial engineering, their performance is limited by structural heterogeneity and low‐efficient energy coupling. This review highlights the emerging paradigm of single‐fiber or in‐fiber artificial muscle design, where actuation functionality is intrinsically encoded within the molecular architecture of individual fibers. We comprehensively examine state‐of‐the‐art material systems such as phase‐transition materials, block copolymer self‐assemblies, mechanically interlocked polymers, covalent supramolecular hybrids, and woven polymer networks. Particular emphasis is placed on the structure–property–function relationships that govern the actuation strain, stress output, response speed, and long‐term durability. We also propose a unified framework for evaluating single fiber actuator performance based on key metrics and critically discuss manufacturing challenges, scalability, and integration with smart sensing system. This review provides a roadmap for molecular design of the high‐performance artificial muscle, offering new strategies for intelligent actuation and soft material systems in real‐world applications.