New Method ultralight Ag nanowires for preparing a controlled density and pore structure of the airgel

In recent years, advances in technology, metal nanowires, scientists have developed a new method for the preparation of a lightweight metal foam under mild conditions, while the density can be customized, also choose a metallic material. In aqueous suspension Cu nanowires, for example, may be prepared lightweight airgel porous Cu or critical point dried by freeze drying. Recently, the California 劳伦兹利弗 Livermore National Laboratory researchers published a study, introduced a new method for preparing a controlled density and pore structure of ultra-light airgel Ag nanowires, the use of this preparation methods for the first time a low density of 4.8mg / cm3 Ag foam performance. Related research published online last week in the journal Nano Letter. ( \”Ultralight Conductive Silver Nanowire Aerogels\”). Previously, 劳伦兹利弗 Livermore National Laboratory in the field of ultra-lightweight materials many achievements. The researchers synthesized by a modified polyol prepared silver nanowire prototype, then purified by selective precipitation. As follows: Configuration of about 100ml containing 0.05mM NaCl, 0.189M PVP, about 0.0014mM AgNO3 and ethylene glycol solution of 0.017mM CuCl2 was added to a round bottom flask was preheated to 185 deg.] C, oil bath for one hour; then, with vigorous 30mL dropwise with stirring a freshly prepared solution of ethylene glycol added AgNO3 (0.12 M); after completion of the reaction, the flask was removed from the oil bath and cooled to room temperature, to obtain a silver nanowire and a small amount of silver nanoparticles. Since the silver nanoparticles have a negative effect on the metal aerogels, researchers selective precipitation of silver nanowires purification. The specific method is washed with a solution of silver nanowires, acetone was added in the washing liquid, due to the different silver nanowire density and silver nanoparticles, silver nanoparticles are suspended in a liquid mainly silver nanowires that are precipitated, the supernatant was discarded solution, the precipitate was re-dispersed in water purification and enrichment nanowires can be realized. The resulting assembly prepared silver nanowires can be used as the conductive silver airgel. Researchers known concentrations of silver nanowire suspension is formed by vortexing in glass vials and then immediately placed in a pre-cooled with liquid nitrogen through the metal blockOn; the presence of a vertical temperature gradient, and gradually grow ice nucleation from the bottom, with the increase of the ice crystals, the silver nanowires are aligned ice redistribution; Frozen silver nanowire suspension freeze-dried, and removing heat PVP, silver nanowires get highly porous airgel. Because of this unique method of preparation, the silver aerogels unique layered porous structure, researchers can be controlled by adjusting the density of the airgel concentration of the silver nanowire suspension lowest to 4.8mg / cm3. Further, by a specially designed mold, also can be prepared aerogels other shapes, such as discs, spheres, hemispheres, and the like. Researchers such silver nanowires aerogels performance test, the conductivity was found to reach 51000s / m. Its mechanical properties test results show that the silver nanowires airgel showed a \”resilient reinforcing\” behavior, the Young\’s modulus of up to 16800Pa. \”Interestingly, the results show that Ag nanowire deformation mechanisms that we prepared with conventional metal foam airgel prepared by different, which is due to bending deformation, which means it has over other foam or airgel higher structural strength, which is another hidden advantage of it, \”the researchers said:\” for such a good performance reasons, it remains to be further modeling to reveal. \”