No abstract

No abstract

No abstract

Free-standing nanoporous nickel (np-Ni) ribbons were directly synthesized by dealloying Mg90-xNixY10 metallic glass ribbons in citric acid aqueous solutions under free conditions. Due to the amorphous nature of the Mg90-xNixY10 precursors, the as-dealloyed samples exhibit a uniform nanoporous structure with the ligament size of ∼7 nm. Effects of alloy composition, leaching time, and acid concentration on the resulting nanoporous microstructure were discussed. The lower limit of Ni content in Mg90-xNixY10 precursors was identified to be 20%, below which the nanoporous Ni could not be formed. Besides, a linear relationship was established between the ligament size and the leaching time on a logarithmic scale. The ultrafine structure of the obtained np-Ni was associated with the stabilizing effect of citric acid. The as-dealloyed samples with the naturally formed oxide surface of NiO were directly examined as binder-free electrodes for high-performance supercapacitors.

The production of natural materials is achieved through a bottom‐up approach, in which materials spontaneously grow and adapt to the external environment. Synthetic materials are specifically designed and fabricated as engineered materials; however, they are far away from these natural self‐growing attributes. Thus, design and fabrication of synthetic material systems to replicate the self‐growing characteristics of those natural prototypes (i.e., hairs and nails) remains challenging. Inspired by the self‐growing behaviors of keratin proteins, here the fabrication of synthetic hydrogels (i.e., polyacrylamide (PAAm)) from the free radical polymerization at the interface between AAm precursor solution and liquid metals (i.e., eutectic gallium–indium (EGaIn)) is reported. The newly formed hydrogel materials at the EGaIn/AAm precursor interface gradually push the whole hydrogel upward, enabling the self‐growing of these synthetic hydrogel materials. This work not only endows the fabrication of synthetic materials with unprecedented self‐growing characters, but also broadens the potential applications of self‐growing materials in actuation and soft robotics.