Stretchable and Highly Sensitive Braided Composite Yarn@Polydopamine@Polypyrrole for Wearable Applications

Abstract

Flexible wearable devices for various applications have attracted research attention in recent years. To date, it is still a big challenge to fabricate strain sensors with a large workable strain range while maintaining their high sensitivity. Herein, we report the fabrication of highly sensitive wearable strain sensors from braided composite yarns (BYs) by in situ polymerization of polypyrrole (PPy) on the surface of yarns after polydopamine templating (BYs–PDA). The electromechanical performance and strain sensing properties of the fabricated braided composite yarn@polydopamine@polypyrrole (BYs–PDA–PPy) were investigated. Because of the unique braided structure of BYs, the BYs–PDA–PPy strain sensors exhibit fascinating performance, including a large workable strain range (up to 105% strain), high sensitivity (gauge factor of 51.2 in strain of 0%–40% and of 27.6 in strain of 40%–105%), long-term stability and great electrical heating performance. Furthermore, the BYs–PDA–PPy sensors can be used in real-time monitoring subtle and large human motions. The BYs–PDA-PPy strain sensors can also be woven into fabrics for large area electric heating. These results demonstrate the potential of BYs–PDA–PPy in wearable electronics.

Tillandsia‐Inspired Hygroscopic Photothermal Organogels for Efficient Atmospheric Water Harvesting

“…Owing to introduction of P‐Py‐DA in the synthesis of polymer network, new peaks at 996 cm −1 and 1617 cm −1 appear in the spectra of P‐Py‐Da/P(SMa‐co‐AAm), attributing to the C−H and C=C out‐of‐plane deformation vibration, respectively . In addition, abundant hydroxyl groups (at 3423 cm −1 ) enable the polymeric skeleton of the POG a high affinity to water molecules, which is conducive to its moisture sorption . In the XPS characterization of polymeric network in the POG, the amino‐like (‐NH 2 ) and amine‐like (‐NH‐) structures are located at the binding energy of 399.2 eV and 399.7 eV, respectively, while the peaks at 400.4 eV and 401.41 eV can be attributed to charged nitrogen species (‐NH + ‐) (Figure i) .…”

Flexible Polydopamine Bioelectronics

“…[157] However, the intrinsic conductive fibers are encountered with problems of dispersion of conductive fibers, and the commercial fibers involve coating adhesion and interfacial strength issues. Therefore, PDA has been used to overcome Strain sensor DTPAM a) GF ≈ 0.1(100%), GF ≈ 0.7 (1000%), ULOD b) > 1000% Subtle c) and large d) [149] Fe/PDA@ENR GF = 16.2 (10%), GF = 37.7 (self-healed), LLOD e) = 0.05% Subtle and large [127] BYs-PDA-PPy g) GF = 51.2 (0-40%), GF = 27.6 (40-105%), sensing range >105% Subtle and large [57] Pressure sensor PC-CNF-GG-glycerol h) Limit of detection = 200 mg, response time = 33 ms Pressure detection [168] PDA-BT the intrinsic drawback of graphene fibers induced by the folding and wrinkling of graphene layers during the spinning process (Figure 12a). [158] Besides promoting the fabrication of graphene, the PDA could be further converted to N-doped graphitic layer upon mild thermal treatment to obtain mechanically strong fibers without sacrificing electrical conductivity, and the prepared graphene fibers simultaneously presented high mechanical (tensile strength 650 MPa) and electrical properties (1.32 × 10 5 S m −1 ).…”

A Route Toward Smart System Integration: From Fiber Design to Device Construction

“…The as‐fabricated PET‐PDA‐PPy braid showed high gauge factors of 51.2 and 27.6 in strain ranges of 0–40% and 40–105%, respectively. The sensing performance located in the high level among fiber‐shaped and fabric‐shaped strain sensors …”