Qingtao Wang

Facile Spray-Coating Process for the Fabrication of Tunable Adhesive Superhydrophobic Surfaces with Heterogeneous Chemical Compositions Used for Selective Transportation of Microdroplets with Different Volumes

In this paper, tunable adhesive superhydrophobic ZnO surfaces have been fabricated successfully by spraying ZnO nanoparticle (NP) suspensions onto desired substrates. We regulate the spray-coating process by changing the mass percentage of hydrophobic ZnO NPs (which were achieved by modifying hydrophilic ZnO NPs with stearic acid) in the hydrophobic/hydrophilic ZnO NP mixtures to control heterogeneous chemical composition of the ZnO surfaces. Thus, the water adhesion on the same superhydrophobic ZnO surface could be effectively tuned by controlling the surface chemical composition without altering the surface morphology. Compared with the conventional tunable adhesive superhydrophobic surfaces, on which there were only three different water sliding angle values: lower than 10°, 90° (the water droplet is firmly pinned on the surface at any tilted angles), and the value between the two ones, the water adhesion on the superhydrophobic ZnO surfaces has been tuned effectively, on which the sliding angle is controlled from 2 ± 1° to 9 ± 1°, 21 ± 2°, 39 ± 3°, and 90°. Accordingly, the adhesive force can be adjusted from extremely low (∼2.5 μN) to very high (∼111.6 μN). On the basis of the different adhesive forces of the tunable adhesive superhydrophobic surfaces, the selective transportation of microdroplets with different volumes was achieved, which has never been reported before. In addition, we demonstrated a proof of selective transportation of microdroplets with different volumes for application in the droplet-based microreactors via our tunable adhesive superhydrophobic surfaces for the quantitative detection of AgNO3 and NaOH. The results reported herein realize the selective transportation of microdroplets with different volumes and we believe that this method would potentially be used in many important applications, such as selective water droplet transportation, biomolecular quantitative detection and droplet-based biodetection.

Enhanced cycling stability of silicon anode by in situ polymerization of poly(aniline-co-pyrrole)

The application of a silicon-based Li-ion battery anode is limited by the poor cycling stability associated with its large volume changes during the charging and discharging processes. Herein, we report a facile solution process to fabricate silicon composite anodes by encapsulating Si nanoparticles with in situ polymerized aniline and pyrrole copolymers. The copolymer matrix can accommodate the considerable volume changes of Si during the cycling process. Therefore, the as-prepared Si/poly(aniline-co-pyrrole) composite electrodes successfully achieve higher capacity and better cycling performance than the bare nano-Si anode. The specific capacity of the composite electrode retains 637 mA h g−1 after 50 cycles.

Sb2O3 nanoparticles anchored on graphene sheets via alcohol dissolution-reprecipitation method for excellent lithium storage properties

Sb2O3 nanoparticles are uniformly anchored on reduced graphene oxide (rGO) sheets via a facile and ecofriendly route based on the alcohol dissolution-reprecipitation method. Such obtained Sb2O3/rGO composite demonstrates a highly reversible specific capacity (1355 mA h g-1 at 100 mA g-1), good rate capability, and superior life cycle (525 mA h g-1 after 700 cycles at 600 mA g-1) when used an anode electrode for lithium-ion batteries (LIBs). The outstanding electrochemical properties of Sb2O3/rGO composite could be attributed to its unique structure in which the strong electronic coupling effect between Sb2O3 and rGO leads to an enhanced electronic conductivity, structure stability, and electrochemical activity during reversible conversion-alloying reactions. Also, these findings are helpful in both developing novel high-performance electrodes for LIBs and synthesizing functional materials in an ecofriendly and economical way.