Smart core-sheath fibers for advanced textiles: Material integration, manufacturing strategies, and applications

Smart textiles have transformed from passive fabrics into intelligent, multifunctional systems that can sense, respond to, and adapt to environmental stimuli. Among the various strategies to achieve such functionality, core-sheath fibers have emerged as versatile and structurally efficient approaches. This design enables the spatial separation and synergistic integration of distinct materials within a single fiber, allowing for the simultaneous optimization of the mechanical, electrical, thermal, and biological properties, thereby surpassing the performance of conventional blended, coated, or composite fibers. This review critically examines recent advances in smart core-sheath fibers, focusing on material integration strategies, interfacial compatibility, and structure-property relationships that determine functional performance. Various fabrication approaches, including coaxial electrospinning, wet spinning, melt spinning, microfluidic spinning, and thermal drawing, have been systematically evaluated for scalability, structural precision, and suitability for core-sheath fiber manufacturing. Furthermore, the review explores applications in wearable electronics, biomedical systems, energy harvesting, protective clothing, and environmental monitoring, where core-sheath structures enhance durability, adaptability, and resilience under mechanical and environmental stresses. Drawing on recent advances in materials science, fiber engineering, and smart textile technology, it provides a unified and holistic framework that connects material design, fabrication processes, and end-use functionality. Persistent challenges, such as interfacial stability, washability, and sustainability, are discussed, along with strategic perspectives and future research directions toward scalable, eco-friendly, and high-performance smart textile systems. • Provides a comprehensive review of smart core-sheath fibers for multifunctional textiles. • Discusses material integration and interfacial design for enhanced fiber performance. • Critically comparing fabrication techniques with focus on scalability and precision. • Highlights diverse applications in wearables, biomedical, energy, and protective textiles. • Identifies key challenges in durability, washability, and sustainability with future outlook.