Superhydrophobic stretchable conductive composite textile with weft-knitted structure for excellent electromagnetic interference shielding and Joule heating performance

Conductive composite textiles (CCTs) as multifunctional integrated platform provide an effective path for developing flexible electromagnetic interference (EMI) shielding composites. However, conventional CCTs suffer from EMI shielding performance failure or the loss of textile's intrinsic properties under large tensile strain. Hence, in this work, a stretchable EMI shielding CCT that retains the inherent attributes of textile is proposed via weft-knitting and in-situ chemical Ag deposition. The complete and continuous silver nanoparticles (AgNPs) conductive networks bring excellent conductivity (38560 S/m) and ultrahigh EMI shielding performance (80.1 dB) in unstretched state. When tensile strain is applied, the fibers are gradually straightened from flexural state within 40 % strain, and then begin to be stretched at bigger strains, which benefits from the weft-knitting structure. Therefore, the conductive networks on the fiber surfaces are well protected from damage in the initial 40 % strain range, resulting in a stable EMI shielding performance (51.7 dB) even after 1000 cycles of 100 % tensile strain. Crucially, the CCT preserves good air permeability, softness and lightness even though a series of modifications and tensile strains are applied. Other than the EMI shielding perforamnce, the excellent superhydrophobicity (the contact angle of 158°) imparts the textile with the capability to tackle complex environments easily. Moreover, the textile can readily be heated to 73.4 °C at a low voltage of 0.5 V, showing outstanding Joule heating performance. Even after a long period of heating (3600 s), the textile maintains superior thermal stability, indicating potential applications in wearable heaters. In brief, this multifunctional CCT has excellent comprehensive properties and is expected to further expand the applications of EMI shielding textiles.