Nano Lett: ultra light silver nanowire aerogel on the flower buds

Foam metal represents a new type of material with unique properties It has a series of advantages such as small density, large surface area, high conductivity, low thermal conductivity, sound insulation and electromagnetic wave absorption However, the conventional methods for preparing these foam metals require harsh preparation conditions, including high temperature, high pressure and strict anaerobic conditions In some cases, they cannot be mass produced The use of nanowires as basic components to prepare Ag aerogels has no such limitations Scientists such as Fang Qian of Lawrence Livermore National Laboratory (LLNL) have developed a new ultra light silver nanowire aerogel It is very light in weight and can even stand on fragile rose buds This new silver aerogel has many advantages such as adjustable density, controlled pore structure, good electrical conductivity and good mechanical properties, making it more attractive in practical applications The researchers used a silver nanowire assembly made from LLNL with a density as low as 4.8 mg / cm 3 and a controllable shape The prototypes of silver nanowires were prepared by polyol synthesis and then purified by selective precipitation Silver aerogels were prepared by freezing casting nanoscale water suspensions, and then sintering the nanowire junctions through hot sintering The scanning electron microscopy of the new ultra light silver nanowire aerogels (source: Nano Letters) is as follows: the configuration contains about 0.05mM NaCl, 0.189M polyvinylpyrrolidone (PVP), 0.0014mM AgNO 3 and 0.017mM CuCl 2 After the reaction, take out the flask and cool it to room temperature to obtain silver nanowires and a small amount of silver nanoparticles In order to reduce the adverse effects of a small amount of silver nanoparticles on the metal aerogels, the experimental researchers were purified by selective precipitation After washing with acetone aqueous solution, silver nanoparticles will be suspended in the washing solution, while silver nanowires will precipitate A brief introduction to the synthesis and purification process of silver nanowires (source: Nano Letters), YongHan, an important researcher of the study, said: "we can manufacture these ultra lightweight silver aerogels because our silver nanowires are of very high quality, and our laboratory's customized raw material synthesis capability enables us to create strict specifications for various applications." The silver nanowires obtained from the experiments can be used as components for preparing conductive silver aerogels In a glass bottle, a certain concentration of silver nanowire suspension is formed into a vortex, and then placed on a cooled metal block The silver nanowire suspension is frozen and dried, and then heat treated to remove PVP A highly porous silver nanowire aerogel is prepared The preparation process of silver nanowire aerogels (source: NanoLetters), through the performance test of silver nanowire aerogels, found that the conductivity of the nanowire aeromel is as high as 51000s/m The mechanical properties test results show that the young modulus of the new silver nanowire aerogel is as high as 16800Pa, indicating that the elastic modulus of the material is relatively small, the rigidity is large, and the deformation is not easy to deform "The unbelievable thing is that the deformation of the new silver nanowire aerogel is bending deformation, which indicates that the aerogel structure has higher strength, which is the one and only advantage," the researchers said In addition, the high porosity, excellent mechanical and electrical properties of Ag nanowire aerogels can improve the device performance and open up new possibilities for fuel cells, catalysis, energy storage, medical devices and sensors Paper link: http://pubs.acs.org/doi/10.1021/acs.nanolet.7b02790