Ying Wang

Conventional carbon fiber (CF) yarn current collectors suffer from severe localized Joule heating and scarce active sites, limiting the high-rate performance and safety of fiber-shaped supercapacitors. Herein, we construct 3D branched burr-structured CF yarns (CFY2, CFY3, and CFY4) via a scalable twist-fracture wrapping strategy. By tuning the twisting intensity, the burr density is systematically regulated from 29.33% to 62.02%. This multipath conduction skeleton promotes macroscopic current sharing, redistributes localized Joule heating, and enhances lateral heat spreading, as evidenced by a significant drop in saturation temperature from 70.1 to 50.2 °C and a broadening of the radial thermal profile full width at half maximum from 43 to 96 pixels. This electrothermal advantage persists after polyaniline (PANI) deposition. The abundant protruding burrs provide an enlarged exposed interface that favors more continuous PANI deposition. Benefiting from the enlarged electrochemically accessible interface, enhanced local ion accessibility to PANI redox sites, and favorable charge-transfer characteristics, the optimized PANI@CFY4 electrode delivers a specific capacitance of 410.0 F g–1 at 0.5 A g–1 with 96.4% retention at 5 A g–1, a charge-transfer resistance of 0.33 Ω·cm2. The assembled symmetric fiber supercapacitor achieves a 1 V voltage window, 26.8 Wh kg–1 at 236.9 W kg–1, and 70.4% capacitance retention after 10,000 cycles under an electrolyte-maintained protocol, while stably powering wearable electronics.

Carbon fiber's (CF) inherent chemical inertness limits its use in wearable energy textiles. This study introduces an innovative helical strain engineering strategy to activate CF's latent electrochemical activity by controllably generating cross‐sectional defects. This low‐energy, scalable mechanical process induces programmable microfracture, creating high‐performance, burr‐enriched CF yarns (CFYs) for stretchable supercapacitors. Controlled twisting coupled with pre‐stretched polyurethane and polyester fibers formed native microdefects with exposed active edge sites and an interconnected 3D conductive network. The optimized CFY4 substrate exhibited ultra‐low resistivity (0.22 Ω·cm), 40% reversible stretchability, and a burr density of 6.51%. Additionally, in situ polymerization of polypyrrole (PPy) on CFY4 produced a pseudocapacitive electrode (CFY4@PPy) with a mass‐specific capacitance of 141.41 F g ⁻¹ at 0.3 A g ⁻¹ , which was 2.5 times higher compared to pristine CF@PPy. The assembled symmetric yarn‐based supercapacitor achieved a wide voltage window of 2.5 V, high energy density of 53.94 Wh kg ⁻¹ at 500 W kg ⁻¹ , cyclic voltammetry curve stability under 30% tensile conditions. Successful demonstrations powering LEDs, sensors, and wearables confirm practical viability. This work provides a new paradigm in carbon material engineering while demonstrating how controlled mechanical deformation can unlock the hidden electrochemical potential of CF for next‐generation wearable energy textiles.

Bio-based polyamide 56 (PA56) is a new sustainable material in the polyamide family. In this study, dyes suitable for PA56 fibers were experimentally screened from natural plants rich in pigments. The results showed that the preferred natural dyes for PA56 fabric are turmeric for a yellow hue, madder for a red hue, catechu for a brown hue, and indigo for a blue hue. A green hue was achieved by the two-bath dyeing method using indigo and turmeric, respectively. For a dyability comparison with conventional PA6 and PA66, PA56, PA6, and PA66 fabrics were woven under identical conditions and dyed with turmeric, madder, catechu, and commercial indigo extracts. PA56 fabric exhibited the best dye uptake and the fastest dyeing rate (PA56 > PA6 > PA66). The reason for the excellent dyeability of PA56 fibers was analyzed in terms of differential scanning calorimetry measurement and molecular dynamics simulations. The results showed that the lowest crystallinity was exhibited by PA56 (PA56 < PA6 < PA66); in addition, PA56 displayed the largest fractional free volume (PA56 > PA6 > PA66). These structural characteristics contribute to the excellent dyeability of PA56 fibers. Therefore, PA56 fibers are promising materials, as they are derived from a sustainable source and have superior dyeing properties compared to PA6 and PA66 fibers.

A new kind of bio-based polyamide 5,6 (PA56) fiber has been synthesized from adipic acid and 1,5-pentanediamine. In this report, the characterization, antistatic treatment, mechanical properties, moisture absorption, mass-specific electrical resistance, and static electricity of the PA56 staple fibers were investigated. The spinnability of the PA56 yarns was studied. The results showed that the breaking strength of the PA56 fibers was 3.55 cN·dtex⁻¹, the breaking elongation was 61.60% and the initial modulus was 49.32 cN·dtex⁻¹. The PA56 staple fibers had an excellent moisture absorption of 4.68% and the easy release of water from the fibers. The release of water absorbed on the staple fibers made the carding processing of the PA56 fibers difficult due to electrostatic aggregation. Thus, an antistatic treatment of the PA56 staple fibers was carried out. Compared with the untreated fibers, the treated fibers exhibited a spectacular improvement in conductivity which led to their high efficiency of carding and good spinnability. The potential of the PA56 staple fibers carding web decreased from +21.2 to +0.04 kv when treated. The mass-specific electrical resistance of the treated PA56 staple fibers decreased from more than 10⁴ MΩ·g·cm⁻² to 290 MΩ·g·cm⁻² both at a relative humidity (RH) of 35%, and from 1500 to 9.5 MΩ·g·cm⁻² both at a 65% RH. The Ring yarn and Siro-spun yarn were successful produced by their spinning systems. The measurement results of the yarns demonstrated that the Siro-spun yarn had better properties than the Ring yarn, such as tensile strength, unevenness (CV%), hairiness index (H) and abrasion resistance.

With more and more attention paid to the quality of life, noise pollution has been ranked the third in environmental pollution. In this study a symmetrical multi-layer sheet was designed for a sound absorbent material. Needleless electro-spinning nano-membranes of polyurethane (PU) were used as the surfaces of the sound absorbent multi-layer sheets. The effects of the PU concentration, solvent ratio, membrane thickness and solvent additives on the surface morphology of the nano-membranes and the sound absorption coefficient of the sound absorbent sheets were carefully investigated by scanning electron microscopy and sound absorption measurements. The results showed that the optimal spinning solution was 10 wt.% PU and the solvents ratio of N,N-dimethylformamide (DMF) and tetrahydrofuran (THF) at 1:1. Under this condition, the average sound absorption coefficient of the multi-layer sheets increased from 0.29 for the 0 mm nano-membranes to 0.57 for the 1.2 mm nano-membranes (spinning time 240 minutes). For the nano-membranes in the range of 0.2–1.2 mm, it was noted that the average sound absorption factor of the multi-layer sheets increased with the increasing of the nano-membranes’ thickness and the absorption frequency for which the highest sound absorption coefficient occurred moved to lower frequencies with the increasing of the membranes’ thickness. By adding sodium dodecyl sulfonate (0.5 wt.%) and sodium chloride (1.0 wt.%) into the optimal solution, a nano-membrane with a nano-cobweb structure of 100% coverage rate was formed. Under the spinning condition of 10 wt.% PU, 1.0 wt.% NaCl, 0.5 wt.% SDS, 1:1 DMF/THF and 240 minutes, a nano-cobweb multi-layer material with an average sound absorption factor of 0.63 was obtained. Although not a large increase from the sound absorption coefficient for the nano-membrane multi-layer sheet material of 0.57, the results showed that the multi-layer sheet with nano-cobweb layer had a great improvement of sound absorption in the range of 500–2000 Hz relative to the nano-membranes. Therefore, a good sound absorption sheet with multi-layer structures was obtained successfully.

In this paper, a green solvent for chitosan, plasma acid, was made and chitosan/plasma-acid solutions were prepared. An environmentally friendly chitosan/polyvinyl alcohol (PVA) nano-membrane was prepared via electrospinning due to the difficulty of electrospinning of pure chitosan/plasma-acid solutions. Two blending methods of chitosan with PVA were investigated. One way was to mix a chitosan/plasma-acid solution (1%) and a PVA/water solution (10%) with the volume ratios of 2:8, 3:7, 4:6, 5:5, 6:4, 7:3 and 8:2, respectively. The results showed that fibrous nano-membranes could start to be formed at a chitosan/PVA mixing ratio of 7:3 up to the ratio of 2:8 with increasing PVA. The average fiber diameters increased with increased adding of PVA, ranging from 74.7 nm for the 7:3 ratio to 280.7 nm for the 2:8 ratio. The other way to prepare the chitosan/PVA solutions was to put PVA and chitosan powders into the plasma acid together. Fibrous nano-membranes could also be formed at 6% PVA and 10% PVA solution, both with 1% chitosan compositions. The average diameters of the resulting nano-fibers were 144.67 nm and 300.7 nm, respectively. The Fourier transform infrared (FTIR) spectroscopy results showed that the chitosan was bonded to the PVA by hydrogen bonds in the nano-membranes (6% PVA, 1% chitosan). It is noted that both of the two blending methods permitted obtaining chitosan/PVA nano-membranes. As indicated, the PVA in the solution had a large effect on the diameters of the nano-fibers. The first method permitted obtaining nano-fibers with smaller diameter. The maximum concentration of chitosan in the solution was 0.7% (7:3 ratio). The second method was simpler and permitted increasing the chitosan concentration in the solution to 1% for both the 6% and 10% concentrations of PVA.

Finger mark identification, which is one of the biological recognition methods, has a history of more than 100 years. In this study, polyvinyl alcohol (PVA)/ninhydrin blend nanomembranes were prepared using needleless electrospinning and applied in latent finger mark detection. The morphology and structure of the PVA/ninhydrin nanomembranes were investigated using scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction. The results showed that the preferable composition for the best spinnability of the complex solution was 86.9 g/L PVA and 76.1 g/L ninhydrin, using water as solvent. The ninhydrin was uniformly dispersed in the PVA/ninhydrin nanomembranes in the amorphous regions. There was a small amount of hydrogen bonds between the PVA and ninhydrin. The addition of ninhydrin did not affect the crystal structure of PVA. When subjected to hot steam of a weak acidic water bath (pH = 6), the PVA/ninhydrin nanomembranes completely displayed the latent invisible finger marks left on glass or ceramic surfaces in purple within 3–5 min of the steam exposure, which were easily observed by the naked eyes. The purple finger marks on the nanomembranes were due to the reaction of ninhydrin with amino acids in sweat released from the fingers. Both chemical cross-linking and physical adhesion of the membrane to the surface occurred in the area of the finger mark regions. Physical adhesion also developed in the regions without finger marks. Therefore, finger marks identification using electrospun PVA/ninhydrin nanomembranes is simple, rapid, harmless, and sensitive, and does not need large instruments or any type of liquid chemical reagent.