Unidirectional Droplet Transport on the Biofabricated Butterfly Wing.

Water droplet unidirectional transport on the asymmetric superhydrophobic surface has attracted much interest in theory analysis and applications, such as self-cleaning, antifogging, anti-icing, heat transfer, and so on. Different from the symmetrical performance on the uniform topographies, the droplets acting on the asymmetric surface exhibit an anisotropic state and easily roll off the surface along the special direction. This phenomenon is indicated by natural butterfly wings. The flexible asymmetrically arranged microstep induces the droplet to release along the outside radial (RO) direction and to pin against the RO direction. Here, inspired by butterfly wings, a kind of surface for superhydrophobic and unidirectional droplet transport is achieved by integrating the methods of soft lithography and enhanced crystal growth. The water droplet shows the anisotropic state on the biofabricated surface, and it rolls off easily along the step direction. The droplet is unidirectionally driven off the surface by the asymmetric surface tension force generated by the microstep topography. This experiment is significant for designing self-cleaning surfaces.

Ca2+ Enhanced Nacre-Inspired Montmorillonite-Alginate Film with Superior Mechanical, Transparent, Fire Retardancy, and Shape Memory Properties.

Inspired by nacre, this is the first time that using the cross-linking of alginate with Ca ions to fabricate organic-inorganic nacre-inspired films we have successfully prepared a new class of Ca2+ ion enhanced montmorillonite (MMT)-alginate (ALG) composites, realizing an optimum combination of high strength (∼280 MPa) and high toughness (∼7.2 MJ m-3) compared with other MMT based artificial nacre. Furthermore, high temperature performance of the composites (with a maximum strength of ∼170 MPa at 100 °C) along with excellent transmittance, fire retardancy, and unique shape memory response to alcohols could greatly expand the application of the mutilfunctional composites, which are believed to show competitive advantages in transportion, construction, and insulations, protection of a flammable biological material, etc.

Nacre-inspired integrated strong and tough reduced graphene oxide-poly(acrylic acid) nanocomposites.

Inspired by the relationship between interface interactions and the high performance mechanical properties of nacre, a strong and tough nacre-inspired nanocomposite was demonstrated based on graphene oxide (GO) and polyacrylic acid (PAA) prepared via a vacuum-assisted filtration self-assembly process. The abundant hydrogen bonding between GO and PAA results in both high strength and toughness of the bioinspired nanocomposites, which are 2 and 3.3 times higher than that of pure reduced GO film, respectively. In addition, the effect of environmental relative humidity on the mechanical properties of bioinspired nanocomposites is also investigated, and is consistent with previous theoretical predictions. Moreover, this nacre-inspired nanocomposite also displays high electrical conductivity of 108.9 S cm(-1). These excellent physical properties allow this type of nacre-inspired nanocomposite to be used in many applications, such as flexible electrodes, aerospace applications, and artificial muscles etc. This nacre-inspired strategy also opens an avenue for constructing integrated high performance graphene-based nanocomposites in the near future.

Supramolecular fabrication of multilevel graphene-based gas sensors with high NO2 sensibility.

This study reports the supramolecular assembly of a silver nanoparticle-naphthalene-1-sulphonic acid-reduced graphene oxide composite (Ag-NA-rGO) and its utilization to fabricate a highly sensitive and selective gas sensor. The prepared supramolecular assembly acted not only as a non-covalent functionalization platform (π-π interaction) but was also an excellent scaffold to fabricate a highly sensitive and selective low concentration NO2 gas sensor. The prepared composites were characterized using several techniques, which revealed that the graphene sheets were dispersed as ultrathin monolayers with a uniform distribution of silver nanoparticles. The fabricated multilevel structure exhibited an excellent sensing performance, i.e. 2.8 times better, towards 10 ppm NO2 compared to the NA-rGO and rGO based sensors. Apart from its high sensitivity, superior reversibility and selectivity, the prepared supramolecular assembly exhibited an outstanding linear response over the large concentration range from 1 ppm to 10 ppm. The obtained results demonstrate that the prepared supramolecular assembly holds great potential in the fabrication of efficient and effective low-concentration NO2 gas sensors for practical applications.

Room temperature fabrication of porous ZnO photoelectrodes for flexible dye-sensitized solar cells.

We fabricated ZnO photoelectrodes at room temperature by doctor-blading ZnO gel; the adequate interparticle connection and the effective ammonia activation process improved the flexible DSC's efficiency to 3.8% (under 100 mW cm(-2)).