Liquid metal micrometer fibers with chain-bead structure for precision sewing in smart textiles applications

Stretchable conductive fibers are essential for lightweight conductors with exceptional electrical conductivity and stability. Gallium-based liquid metal has gained significant attention in this field due to its high electrical conductivity, intrinsic deformability and biocompatibility. In this work, we introduce a novel approach to fabricate liquid metal micrometer fibers with chain-bead structure (LMFCB) by high-pressure jetting. These fibers feature extremely thin line widths (≈22 μm) and a distinctive chain-bead structure, allowing for adjustable fiber resistances to change with the density of chain-bead. The chain and bead in this structure is evenly spaced, enabling fine-tuning of resistance by adjusting the distance between the beads. For instance, adjusting the jetting pressure from 0.4 to 1.0 MPa increases the distance between the beads, resulting in a resistance change of the LMFCB from 9.25 to 28.77 Ω. Moreover, this unique configuration significantly enhances the dynamic stability of the resistance of fibers. Over a 40 % stretching range, the fibers with chain-bead structure exhibits a resistance change of 44.54 %, significantly lower than the 96 % resistance change observed without chain-bead structure. Additionally, the cryogenic freezing process dramatically enhances the mechanical strength of the fibers through a liquid–solid phase transition, allowing them to be seamlessly integrated into elastic fabrics using simple sewing methods. These fibers not only exhibit excellent conductivity and stability but also conformability, indicating promising applications in smart textiles and wearable devices.