Current synthetic elastomers suffer from the well‐known trade‐off between toughness and stiffness. By a combination of multiscale experiments and atomistic simulations, a transparent unfilled elastomer with simultaneously enhanced toughness and stiffness is demonstrated. The designed elastomer comprises homogeneous networks with ultrastrong, reversible, and sacrificial octuple hydrogen bonding (HB), which evenly distribute the stress to each polymer chain during loading, thus enhancing stretchability and delaying fracture. Strong HBs and corresponding nanodomains enhance the stiffness by restricting the network mobility, and at the same time improve the toughness by dissipating energy during the transformation between different configurations. In addition, the stiffness mismatch between the hard HB domain and the soft poly(dimethylsiloxane)‐rich phase promotes crack deflection and branching, which can further dissipate energy and alleviate local stress. These cooperative mechanisms endow the elastomer with both high fracture toughness (17016 J m⁻²) and high Young's modulus (14.7 MPa), circumventing the trade‐off between toughness and stiffness. This work is expected to impact many fields of engineering requiring elastomers with unprecedented mechanical performance.

Four different models (corresponding to different loading conditions) of first principles tensile tests are employed to determine cohesion and strength of several interfaces, namely coherent interfaces of two fcc metals (Ni/Ag and Ni/Cu) and symmetrical tilted Σ5(210) grain boundary in fcc nickel (clean as well as sulfur-decorated). The purpose of this study is to compare the selected models of tensile tests and to critically discuss their advantages and limitations. Particular attention is paid to differences in their predictions, their ability to identify the weakest link in the studied system and the supercell-size convergence of the computed data. Selection of an appropriate model can be the crucial point in a computer assisted design of advanced materials with interfaces such as multilayered systems.

The extraordinary deformation and loading capacity of nine different [∞]carbohelicene springs under uniaxial tension up to their fracture were computed using the density functional theory.

We present an ab initio and atomistic study of the stress-strain response and elastic stability of the ordered Fe ${}_3$ Al compound with the D0 ${}_3$ structure and a disordered Fe-Al solid solution with 18.75 at.% Al as well as of a nanocomposite consisting of an equal molar amount of both phases under uniaxial loading along the [001] direction. The tensile tests were performed under complex conditions including the effect of the lateral stress on the tensile strength and temperature effect. By comparing the behavior of individual phases with that of the nanocomposite we find that the disordered Fe-Al phase represents the weakest point of the studied nanocomposite in terms of tensile loading. The cleavage plane of the whole nanocomposite is identical to that identified when loading is applied solely to the disordered Fe-Al phase. It also turns out that the mechanical stability is strongly affected by softening of elastic constants $C^{\prime }$ and/or $C_{66}$ and by corresponding elastic instabilities. Interestingly, we found that uniaxial straining of the ordered Fe ${}_3$ Al with the D0 ${}_3$ structure leads almost to hydrostatic loading. Furthermore, increasing lateral stress linearly increases the tensile strength. This was also confirmed by molecular dynamics simulations employing Embedded Atom Method (EAM) potential. The molecular dynamics simulations also revealed that the thermal vibrations significantly decrease the tensile strength.