Superhydrophobic, Elastic, and Conducting Polyurethane-Carbon Nanotube–Silane–Aerogel Composite Microfiber

Abstract

Flexible fibers composed of a conductive material mixed with a polymer matrix are useful in wearable electronic devices. However, the presence of the conductive material often reduces the flexibility of the fiber, while the conductivity may be affected by environmental factors such as water and moisture. To address these issues, we developed a new conductive fiber by mixing carbon nanotubes (CNT) with a polyurethane (PU) matrix. A silane ((heptadecafluoro–1,1,2,2–tetra–hydrodecyl)trichlorosilane) was added to improve the strain value of the fiber from 155% to 228%. Moreover, silica aerogel particles were embedded on the fiber surface to increase the water contact angle (WCA) and minimize the effect of water on the conductivity of the fiber. As a result, the fabricated PU-CNT-silane-aerogel composite microfiber maintained a WCA of ~140° even after heating at 250 °C for 30 min. We expect this method of incorporating silane and aerogel to help the development of conductive fibers with high flexibility that are capable of stable operation in wet or humid environments.

Stretchable One-Dimensional Conductors for Wearable Applications

“…CNT yarns have been studied for potential applications in electrical wirings, sensors, actuators, and energy-storage devices. ,,− However, conventional CNT yarns are straight and lack the elasticity required for stretchable conductors. The resistance of the yarn can only be maintained within a strain level below 1%, which is then increased dramatically because of sliding between CNTs that is irreversible to cause fracture and rapid degradation of electrical conductivity under even small strains (<10%).…”

Woven Agarose–Cellulose Composite Aerogel Fibers with Outstanding Radial Elasticity for Personal Thermal Management

“…Hu et al combined controlled proton absorption gelation spinning with heat-induced cross-linking to prepare hierarchical Zylon aerogel fibers (HZAFs) with high breaking strength and flame retardancy . The second category uses a combination of two or more precursors to produce strong interactions, such as hydrogen bonds, synergy, and intermolecular entanglement, which improves the mechanical properties of the resulting fibers. − For example, Hong et al added silane to a polyurethane–carbon nanotube (PU-CNT) matrix to form a strong PU-CNT-silane aerogel network, thereby improving the mechanical properties of the aerogel fibers . The third category uses a core/shell structure with a high-strength polymer or cellulose as the shell or inner core to improve the mechanical properties of the aerogel fibers. − For example, Yang et al used cellulose acetate/poly(acrylic acid) (CA/PAA) hollow fibers to encapsulate fibrin solutions .…”

Polymer Adsorbents vs. Functionalized Oxides and Carbons: Particulate Morphology and Textural and SurfaceCharacteristics

“…Therefore, additional methods, such as small-angle X-ray or neutrons scattering (SAXS, SANS) [ 53 , 54 , 55 , 56 , 57 , 58 ], X-ray diffraction (XRD) [ 59 , 60 , 61 ], high-resolution transmission (HRTEM) and scanning (SEM) electron microscopies [ 59 , 62 ], nuclear magnetic resonance (NMR) spectroscopy with cryoporometry and relaxometry [ 15 , 63 , 64 , 65 ], differential scanning calorimetry (DSC) and thermoporometry [ 66 ], infrared spectroscopy (FTIR), thermogravimetry (TG) and thermoporometry, dielectric relaxation spectroscopy (DRS), thermally stimulated depolarization current (TSDC) and relaxometry, theoretical simulations, etc. [ 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 , 79 , 80 , 81 , 82 , 83 , 84 , 85 , 86 ] should be used. Besides the textural characteristics, the data of these methods allow one to obtain information on the materials’ behavior under different conditions, which could model real situations related to practical applications.…”