Droplet splitting is a fascinating interfacial phenomenon, which shows great potential in applications such as fluid dispending and liquid spraying. Splitting behaviors of droplet impact on structured superhydrophobic surfaces are highly transient and complex, but the underlying mechanism is far from clear. Here, we report the splitting dynamics on ridged superhydrophobic surfaces through experimental and theoretical investigations. As the Weber number increases, three splitting modes appear in sequence: non-splitting, departure splitting, and contact splitting. Based on the movement of the liquid film behavior on the ridge along the axial direction, the splitting time consists of durations of three stages: axial spreading, axial retraction, and oscillation retraction, and it decreases with the increasing Weber number. A theoretical model is further established to predict the splitting time, where the law of the axial spreading and retraction is revealed. Splitting dynamics can be regulated by the geometric shape of the ridge. Droplet splitting is inhibited on the rectangular ridge, while the splitting time and contact time are effectively reduced on the semi-cylindrical and triangular ridges. This work is expected to provide fundamental support for diverse applications related to droplet splitting and offer guidance for the design of superhydrophobic surfaces.
A composite gel electrolytes containing poly(1-butyl-3-vinylimidazolium bis(trifluoromethanesulfonyl)imide), 1-propyl-3-methylimidazolium iodide and graphene oxide are prepared for dye-sensitized solar cells, without any volatile organic solvent.
Rolling and annealing are common composite processes of Copper/Aluminum composites (Cu/Al), but the formation of intermetallic compounds (IMCs) at Cu/Al interfaces and their relationship with processing conditions still lack a nanoscale understanding. Here, we use molecular dynamics (MD) method to simulate the formation of IMCs at Cu/Al interface under different rolling and annealing process parameters with their formation mechanisms quantitatively analyzed. XRD, RDF and potential energy analysis show that rolling promotes the formation of interfacial IMCs, because copper and aluminum atoms tend to diffuse into each other at the interface and combine to form IMCs during rolling. The effects of different size ratios of copper to aluminum and annealing on IMCs are also evaluated. By studying the equivalent phonon thermal conductivity of the interfacial layer and shear strength, it is shown that IMCs enhances interfacial phonon heat transfer, but reduce the interfacial shear strength due to their brittle and hard properties. In addition, the rolling and annealing processes are able to change the dislocation density, thereby affecting the phonon scattering and shear strength of Cu/Al. These results are expected to guide improved directions for the process optimization of high-performance Cu/Al.
Pyrolyzing Fe- and N-contained precursor together or separately with graphene results in codoped graphene dominated by bonded or separated Fe and N configuration, respectively. While the FeN bonded case greatly enhances activity toward oxygen reduction, the separated one does not. This rationally designed Fe and N codoped 3D graphene exhibits superior electrocatalytic activity than the state-of-the-art Pt/C catalyst. As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re-organized for online delivery, but are not copy-edited or typeset. Technical support issues arising from supporting information (other than missing files) should be addressed to the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.
Ultrafine Pt nanoparticles supported on a robust 3D N-doped porous graphene (PtNP/R-3DNG) composite are fabricated. The composite exhibits a considerable enhancement of activity and stability toward the methanol electrooxidation reaction. The robust 3D porous structure and abundant nitrogen atoms are believed to be responsible for the enhanced performance.
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