Liquid metals (LMs) characterized with high conductivity and inherent deformability are potential materials for stretchable electronics and circuits. However, technological challenges associated with facile and efficient patterning of LMs currently impede their widespread implementation. Here, we present an environmentally friendly approach for the facile fabrication of stretchable conductors and circuits through the self-assembly of aqueous LM inks. This process leverages the anisotropic surface characteristics that drive the movement of the ink from hydrophobic to hydrophilic regions. Simultaneously, the ink with a stabilizer mitigated the premature deposition of LM particles. This culminated in the precise deposition of LM particles in accordance with the desired patterns on the substrate. The resulting LM patterns exhibit high resolution (<100 μm line width), high conductivity (2.0 × 10⁵ S m−1), and excellent electromechanical durability. Further demonstrated applications including stretchable displays, three-dimensional touch sensors and soft actuators showcase the versatility of this fabrication for stretchable electronics.
Ni–Mn–Ga polycrystalline alloy fibers with diameters of 33 μm are reported to exhibit significantly improved ductility and huge superelastic and shape memory strains in comparison to conventional brittle bulk polycrystalline alloys. Particularly, the recoverable strain of the Ni54.9–Mn23.5–Ga21.6 fiber can be as high as 10% at 40 °C. Such optimized behavior has been achieved by a suitable fabrication process via a glass-coating melt spinning method. The superelastic properties at different temperatures and the shape memory effect of Ni54.9–Mn23.5–Ga21.6 fibers were investigated.
Cu–Sn shape-memory microw ires were fabricated by a glass-coated melt spinning method. Effects of Sn content on the microstructure and mechanical properties of microwires were investigated. The phase transforms from martensite to austenite with an increase in Sn from 14.0 atomic percent (at.%) to 16.5 at.%. When the Sn content exceeds 16.5 at.%, a highly ordered intermetallic phase, δ, formed. The fracture stress (σf) and the critical stress for martensitic transformation (σMs) increases with an increase in Sn content. The mechanical properties as well as the superelasticity were greatly improved by a high cooling rate in the glass-coated melt spinning method. A bamboo-grained structure was formed in the Cu–Sn microwire with a Sn content of 16 at.% by annealing at 750 °C for 5 h before quenching in water. The results indicate that two opposite strategies of refining the grain size to the micrometer level, or increasing the grain size to a one dimensional size of specimen, e.g., the diameter of the wire, are both effective in improving the superelasticity of the Cu–Sn alloy.
Glass-coated Fe76.5−xCu1NbxSi13.5B9 (x = 0, 1, 2, 3, 3.5) fibers were successfully fabricated by a modified Taylor method. The fibers showed circular morphology and smooth surface with different diameters. The mechanical properties of the fibers were evaluated and the Weibull statistical analysis has been introduced to characterize the strength reliability of the fibers, with the modulus m of the amorphous fibers reaching above 20. The magnetic properties were also studied. Lower coercivity was found for the fibers with amorphous, nanocrystalline, and microcrystalline structures rather than that for the coarse crystalline ones. The glass-coated FeCuNbSiB amorphous fibers have excellent comprehensive performance compared with the other kind of fibers.
Cu-Sn shape-memory microwires were fabricated by a glass-coated melt spinning method. Effects of Sn content on the microstructure and mechanical property of microwires were investigated. The phase transforms from martensite to austenite with Sn content increasing from 14.0 atomic percent (at.%) to 16.5 at.%, and highly ordered intermetallic phase, δ, formed with higher Sn content. The fracture stress, σf, and the critical stress for martensitic transformation, σMs, increases with Sn content increasing. The mechanical property as well as superelasticity were improved greatly by high cooling rate of the glass-coated melt spinning method.