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The rapid development of wearable electronics has placed higher demands on the design strategies of triboelectric materials. Aerogels have the potential to become advanced triboelectric materials, however, traditional design strategies often require complex processes and additional chemical cross‐linking agents to improve the stability of the gel structure, which limits its practical application. In this work, a scalable and sustainable self‐assembly drive strategy is proposed for the design of bio‐based triboelectric aerogels with multi‐scale winding structures. Interestingly, the autoacceleration effect, which is regarded as “unfavorable” during the autocatalytic polymerization of supramolecules, is rationally exploited to provide the supramolecules within the matrix with an abundance of multiple hydrogen bonds at the same time as their rapid gelation occurs. Thanks to this, the aerogel film exhibits ultra‐high tensile strength (104 MPa) and remains undeformed after resisting an impact of 8000 times its own weight. Highly robust triboelectric aerogel films are used to build wearable self‐powered sensors with ultra‐fast response in complex environments (48 ms), while enabling real‐time interaction between the wearer and the information network. The design idea of “ turning a detriment into an asset ” in this work provides a new idea for the material construction of highly robust wearable sensors. [ABSTRACT FROM AUTHOR]

Gas‐sensitive materials are capable of dynamic identification and content monitoring of specific gases in the environment, and their applications in the field of gas sensing are promising. However, weak adsorption properties are the main challenge limiting the application of gas‐sensitive materials. A highly adsorbent gas‐sensitive cellulose nanofibril (CNF)‐based triboelectric material with a layered structure is prepared here and it is applied to self‐powered gas sensing. The layered structure of the triethoxy‐1H,1H,2H,2H‐tridecafluoro‐n‐octylsilane cellulose nanofiber (PFOTES‐CNF)‐based gas‐sensitive material further enhances the adsorption of the material due to electrostatic adsorption in the electrostatic field induced by triboelectricity. It is found that the ammonia‐sensitive material obtained by loading Ti3C2Tx in PFOTES‐CNF has a fast response/recovery (12/14 s), high sensitivity response (Vair/Vgas = 2.1), high selectivity response (37.6%), and low detection limit (10 ppm) for 100 ppm of ammonia gas. In addition, the ammonia‐sensitive CNF‐based triboelectric material can accurately identify NH3 concentration changes in the range of 10–120 ppm and transmit the signal wirelessly to the user interface, facilitating real‐time online monitoring of NH3 in the environment. A novel strategy is provided here for designing and preparing high‐performance gas‐sensitive composites and the analysis of self‐powered gas sensing is guided. [ABSTRACT FROM AUTHOR]

Synthetic polymer materials such as paraformaldehyde and polyamides are widely used in the field of energy engineering. However, they pose a challenge to environmental sustainability because they are derived from petrochemicals that are non‐renewable and difficult to degrade in the natural environment. The development of high‐performance natural alternatives is clearly emerging as a promising mitigation option. Inspired by natural bamboo, this research reports a "three‐step" strategy for the large‐scale production of triboelectric materials with special nanostructures from natural bamboo. Benefiting from the special hierarchical porous structure of the material, Bamboo/polyaniline triboelectric materials can reach short‐circuit current of 2.9 µA and output power of 1.1 W m–2 at a working area of only 1 cm2, which exceeds most wood fiber‐based triboelectric materials. More importantly, it maintains 85% energy harvesting after an extreme environment of high temperature (200 °C), low temperature (−196 °C), combustion environment, and multiple thermal shocks (ΔT = 396 °C). This is unmatched by current synthetic polymer materials. This work provides new research ideas for the construction and application of biomass structural materials under extreme environmental conditions. [ABSTRACT FROM AUTHOR]

Existing models of wellbore stability idealize the borehole wall as either a perfectly permeable or an entirely impermeable surface. The widespread observation that a shale borehole allows solvent molecules to pass through but impedes solutes suggests that the borehole wall should be regarded as a non‐ideal semi‐permeable medium. To address the magnitude and rate of fluid penetration into the formation when a semi‐permeable wellbore is exposed to a non‐isothermal drilling fluid quantitatively, this work develops analytical solutions for a semi‐permeable borehole undergoing convective cooling and far‐field non‐hydrostatic in situ stresses in the framework of fully coupled thermoporoelasticity. Integral transform and load decomposition techniques are employed to facilitate the derivation of analytical solutions. The results show that, in contrast to the permeable or impermeable borehole models, the semi‐permeable model predicts significantly different stress and pore pressure fields. The transient evolution of temperature, pore pressure, and stresses is predominantly governed by two non‐dimensional numbers: the Biot number Bi and a newly identified number πf that characterizes the capability of shale to transport fluid across the solid‐fluid interface. [ABSTRACT FROM AUTHOR]

This study introduces a simple analytical model for fracture toughness to bridge the length scales from grain size to bulk thickness by assembling a virtual crack path from the angles recorded on an unfractured microstructure, which is a great challenge in fracture mechanics due to the high geometrical complexity. Good agreement is found between a crack deflection angle distribution measured from 5764 crack segments and the prediction by the model and the possible influence of residual stress is quasi quantitatively discussed. A total of 7.4% of the crack segments observed acted as crack bridges, while 7.3% was predicted by the model. A quantification of how high an angle needs to be to turn crack deflection into crack bridging is given. The ratio of fracture toughness from grain boundary to grain, G1c(gb)/G1c(g), was measured indirectly from all samples to be between 0.3 and 0.35. [ABSTRACT FROM AUTHOR]