Fiber materials are highly desirable for wearable electronics that are expected to be flexible and stretchable. Compared with rigid and planar electronic devices, fiber-based wearable electronics provide significant advantages in terms of flexibility, stretchability and breathability, and they are considered as the pioneers in the new generation of soft wearables. The convergence of textile science, electronic engineering and nanotechnology has made it feasible to build electronic functions on fibers and maintain them during wear. Over the last few years, fiber-shaped wearable electronics with desired designability and integration features have been intensively explored and developed. As an indispensable part and cornerstone of flexible wearable devices, fibers are of great significance. Herein, the research progress of advanced fiber materials is reviewed, which mainly includes various material preparations, fabrication technologies and representative studies on different wearable applications. Finally, key challenges and future directions of fiber materials and wearable electronics are examined along with an analysis of possible solutions. Graphical abstract

Highlights The 3D honeycomb-like fabric decorated with MXene is woven as solar evaporator. The honeycomb structure enables light-trapping and recycling of convective and radiative heat. The 3D honeycomb-fabric evaporator possesses high solar efficiency up to 93.5% under 1 sun irradiation and excellent salt harvesting ability. AbstractSection Abstract Solar steam generation technology has emerged as a promising approach for seawater desalination, wastewater purification, etc. However, simultaneously achieving superior light absorption, thermal management, and salt harvesting in an evaporator remains challenging. Here, inspired by nature, a 3D honeycomb-like fabric decorated with hydrophilic Ti₃C₂T_x (MXene) is innovatively designed and successfully woven as solar evaporator. The honeycomb structure with periodically concave arrays creates the maximum level of light-trapping by multiple scattering and omnidirectional light absorption, synergistically cooperating with light absorbance of MXene. The minimum thermal loss is available by constructing the localized photothermal generation, contributed by a thermal-insulating barrier connected with 1D water path, and the concave structure of efficiently recycling convective and radiative heat loss. The evaporator demonstrates high solar efficiency of up to 93.5% and evaporation rate of 1.62 kg m⁻² h⁻¹ under one sun irradiation. Moreover, assisted by a 1D water path in the center, the salt solution transporting in the evaporator generates a radial concentration gradient from the center to the edge so that the salt is crystallized at the edge even in 21% brine, enabling the complete separation of water/solute and efficient salt harvesting. This research provides a large-scale manufacturing route of high-performance solar steam generator.

Commercial wearable piezoelectric sensors possess excellent anti-interference stability due to their electronic packaging. However, this packaging renders them barely breathable and compromises human comfort. To address this issue, we develop a PVDF piezoelectric nanoyarns with an ultrahigh strength of 313.3 MPa, weaving them with different yarns to form three-dimensional piezoelectric fabric (3DPF) sensor using the advanced 3D textile technology. The tensile strength (46.0 MPa) of 3DPF exhibits the highest among the reported flexible piezoelectric sensors. The 3DPF features anti-gravity unidirectional liquid transport that allows sweat to move from the inner layer near to the skin to the outer layer in 4 s, resulting in a comfortable and dry environment for the user. It should be noted that sweating does not weaken the piezoelectric properties of 3DPF, but rather enhances. Additionally, the durability and comfortability of 3DPF are similar to those of the commercial cotton T-shirts. This work provides a strategy for developing comfortable flexible wearable electronic devices.

A series of new polyethylene glycol functionalized dicationic ionic liquids with alkyl or polyfluoroalkyl substitutents (9–17 and 19–24) has been prepared. Important physical properties of these liquids, including glass transition (T_g) and decomposition temperatures (T_d), solubility in common solvents, density (d) and viscosity (η), were measured. These ionic liquids show high thermal stability and good lubricity. In general, imidazolium based dicationic liquids have higher T_d (>415 °C) than their triazolium analogues. The introduction of polyfluoroalkyl groups boosts antiwear properties but also leads to a decrease in T_d. These ionic liquids also exhibit excellent tribological characteristics even at 300 °C, which suggests use as high temperature lubricants.