Superhydrophobic Plant Leaves with Micro-line Structures： An Optimal Biomimetic Objective in Bionic Engineering

It has been well demonstrated that there are two kinds of surface morphologies, including binary structures （namely micro-and nanostructures） and less common unitary structures （such as micro-line structures）, which play crucial roles in endowing the plant leaves with superhydrophobic properties. In this work, five superhydrophobic plant leaves in nature are introduced, by means of the combination of surface morphology and wettability with the aid of Scanning Electron Microscopy （SEM） and contact angle measurement. The results indicate that either the binary structures or the unitary structures enable the construction of a superhydrophobic surface, and the latter shows likely better mechanics compared with the former according to the corresponding theory. This research aims at introducing two different types of corresponding morphologies of superhydrophobic plant leaves.

Research progress on the development mechanism and exploratory protection of the scaling off on earthen sites in NW China

The scaling off is among the most pervasive and severe deterioration types.The scaling off developed on earthen sites in Northwest China has a special and complex binary structure composed of crusted and loose layers.Under the synergistic functions of external environmental elements such as rainfall,temperature,and wind,and rammed earth properties,this deterioration has gradually created the crust on the site’s surface,and has then evolved into exfoliation and finally fallen off,leading to the reciprocating progressive destruction of earthen sites.Therefore,determining the development mechanism of scaling off and implementing targeted protection measures for the scientific conservation of earthen sites has become essential.In this review study,the properties of the building material causing the binary structure and the coupling effects of water,temperature,salt,and wind on the development of scaling off were determined,and the quantitative evaluation system for this deterioration development was elaborated.After interpreting the reasons for the development of the scaling off,protective measures including chemical grouting,electro-osmosis grouting,and overlay applications were stated.This study also pointed out the research hotspots and shortage in the study process on the scaling off.The hotspots generally focused on the development mechanism of binary structure,quantitative assessment of the degree of development,and related scientific consolidation measures.The shortcomings around the above directions include less attention to the development characteristics and mechanism of scaling off on earthen sites under special environment types,optimization and applicability of quantitative evaluation models,and the development and feasibility of reinforcement slurries and methods.This study can be beneficial in providing theoretical support for the scientific conservation and engineering practice of the scaling off on the earthen sites.

Dip-coating processed sponge-based electrodes for stretchable Zn-MnO2 batteries

Stretchable electronics are in high demand for next-generation wearable devices, but their fabrication is still challenging. Stretchable conductors, flexible pressure sensors, and foldable light-emitting diodes （LEDs） have been reported; however, the fabrication of stable stretchable batteries, as power suppliers for wearable devices, is significantly behind the development of other stretchable electronics. Several stretchable lithium-ion batteries and primary batteries have been fabricated, but their low capacities and complicated manufacturing processes are obstacles for practical applications. Herein, we report a stretchable zinc/manganese-oxide （Zn-MnO2） full battery based on a silver-nanowire- coated sponge prepared via a facile dip-coating process. The spongy electrode, with a three-dimensional （3D） binary network structure, provided not only high conductivity and stretchability, but also enabled a high mass loading of electrochemically active materials （Zn and MnO2 particles）. The fabricated Zn-MnO2 battery exhibited an areal capacity as high as 3.6 mAh·cm^-2 and could accommodate tensile strains of up to 100% while retaining 89% of its original capacity. The facile solution-based strategy of dip-coating active materials onto a cheap sponge-based stretchable current collector opens up a new avenue for fabricating stretchable batteries.