Consecutive mechanical loading cycles cause irreversible fatigue damage and residual strain in gels, affecting their service life and application scope. Hysteresis-free hydrogels within a limited deformation range have been created by various strategies. However, large deformation and high elasticity are inherently contradictory attributes. Here we present a nanoconfined polymerization strategy for producing tough and near-zero-hysteresis gels under a large range of deformations. Gels are prepared through in situ polymerization within nanochannels of covalent organic frameworks or molecular sieves. The nanochannel confinement and strong hydrogen bonding interactions with polymer segments are crucial for achieving rapid self-reinforcement. The rigid nanostructures relieve the stress concentration at the crack tips and prevent crack propagation, enhancing the ultimate fracture strain (17,580 ± 308%), toughness (87.7 ± 2.3 MJ m) and crack propagation strain (5,800%) of the gels. This approach provides a general strategy for synthesizing gels that overcome the traditional trade-offs of large deformation and high elasticity.
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http://dx.doi.org/10.1038/s41563-023-01697-9 | DOI Listing |
Nat Commun
January 2025
Department of Earth Sciences, University College London, London, UK.
Earthquakes are produced by the propagation of rapid slip along tectonic faults. The propagation dynamics is governed by a balance between elastic stored energy in the surrounding rock, and dissipated energy at the propagating tip of the slipping patch. Energy dissipation is dictated by the mechanical behaviour of the fault, which is itself the result of feedbacks between thermo-hydro-mechanical processes acting at the mm to sub-mm scale.
View Article and Find Full Text PDFSci Rep
January 2025
School of Resources and Civil Engineering, Northeastern University, Shenyang, 110819, China.
Based on the symmetric initiation mechanism of double-wing cracks in coal rock mass induced by high-pressure electro-recoil water pressure, fracturing experiments have been performed on coal rock mass under different water pressures and discharge conditions using high-voltage electric pulse hydraulic fracturing devices. Combined with CT scans, the crack spatial distribution inside the post-break coal rock mass was analyzed and found that the edge of the water injection hole is prone to produce double-wing cracks along the drilling hole diameter. ABAQUS is used to verify the physical test and extend the test conditions, the geometric parameter change, morphological expansion rule and crack initiation mechanism of double-wing crack in coal rock mass under different discharge conditions and ground stress conditions are studied.
View Article and Find Full Text PDFAdv Sci (Weinh)
January 2025
Shaanxi Key Laboratory of Fiber Reinforced Light-Weight Composites, State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an, 710072, China.
Multicomponent Ti-containing ultra-high temperature ceramics (UHTCs) have emerged as more promising ablation-resistant materials than typical UHTCs for applications above 2000 °C. However, the underlying mechanism of Ti improving the ablation performance is still obscure. Here, (Hf,Zr,Ti)B coatings are fabricated by supersonic atmospheric plasma spraying, and the effects of Ti content on the ablation performance under an oxyacetylene flame are investigated.
View Article and Find Full Text PDFiScience
January 2025
School of Civil Engineering and Architecture, Zhejiang University of Science & Technology, Hangzhou, P.R. China.
A possibility of unprecedented architecture may be opened up by combining both vertical and in-plane heterostructures. It is fascinating to discover that the interlayer stress transfer, interlayer binding energy, and interlayer shear stress of bi-layer Gr/hBN with CNTs heterostructures greatly increase (more than 2 times) with increase the numbers of CNTs and both saturate at the numbers of CNTs = 3, but it causes only 10.92% decrease in failure strain.
View Article and Find Full Text PDFMicrosc Microanal
January 2025
Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin 14195, Germany.
In catalysis research, the amount of microscopy data acquired when imaging dynamic processes is often too much for nonautomated quantitative analysis. Developing machine learned segmentation models is challenged by the requirement of high-quality annotated training data. We thus substitute expert-annotated data with a physics-based sequential synthetic data model.
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