The self-propelled motion of droplets driven by a surface wetting gradient leads to electricity generation without any external energy input.

Layered molybdenum disulfide (MoS₂) exhibits rich electronic and optical properties and possesses vastly differing characteristic dimensions. A multi-layer MoS₂ membrane represents the critical hierarchical structure which bridges the length-scale of monolayer and bulk material architectures. In this study, the in-plane mechanical properties of MoS₂ membranes were investigated by in situ SEM tensile testing. Under the uniaxial tensile loading, brittle fracture caused failure in a highly localized region of the MoS₂ membranes and their mechanical properties showed a thickness effect: the strengths of the relatively thicker MoS₂ membranes (thickness around hundreds of nanometers) distribute from ∼100 to ∼250 MPa, while the corresponding values of the MoS₂ nanosheets (thickness around tens of nanometers) increase significantly to more than 1 GPa. Upon molecular dynamics (MD) simulations on the fractures of MoS₂ with various thicknesses/layers, the thicker MoS₂ membranes show interplanar fracture, and the typical MoS₂ nanosheets demonstrate the transition from interplanar to intraplanar fractures, while monolayer and few-layer MoS₂ are dominated by intraplanar fracture. Our study provides some critical insights into the mechanical properties and fracture behavior of layered MoS₂ 2D materials, which could be of value for their flexible electronic, optoelectronic and nano-electro-mechanical system (NEMS) applications.

High ORR activity of low Pt ₃ loading model core–shell (monolayer Pd) catalyst.

Stacking faults, as defects of disordered crystallographic planes, are one of the most important slipping mechanisms in the commonly seen lattice, face-centered cubic (FCC). Such defects can initiate twinning which strengthens mechanical properties, e.g. twinning-induced plasticity (TWIP), of high entropy alloys (HEAs) at cryogenic temperatures. In this work, by using density functional theory (DFT), the twinning initiated from stacking faults is discussed with regard to two different solute elements, Al and Mo, in the FeNiCoCr HEAs. Our results show that adding aluminum (Al) has noticeable enhancement of twinnability while molybdenum (Mo) only induces more stacking faults in the FeNiCoCr-based HEAs.