High-performance nanocomposite blocks are expected to be industrialized

University of Science and Technology of China Yushu Hong research team used a novel biosynthesis for the first time to prepare a series of macro-scale functional nanocomposites, the innovations recently published online in the "National Science Review." The method can be flexibly combined with the current bacterial cellulose production process in the food industry, and is expected to realize the industrial production of high-performance nano composite material blocks, and has broad application prospects.

The biosynthetic method developed by the research team is a solid substrate-aerosol biosynthesis method. The method stabilizes the interface of microbial synthesis of nanocellulose by replacing the traditional liquid fermentation substrate of Acetobacter xylinum with a solid state, and deposits different nano-cells on the nanocellulose growth interface through program control to realize nanocellulose and nanocells. For the first time, a series of macroscopic large-scale bacterial cellulose nanocomposites with controllable and regular shape of nanostructured units were successfully prepared. Compared with the traditional slurry method, the biosynthesis process completely retains the three-dimensional nano-network structure of the bacterial cellulose, and the prepared composite material has better mechanical strength while retaining the nano-scale nano-scale excellent performance.

Studies have shown that this synthesis is a versatile method for preparing a series of macroscopic composite blocks composed of different nanomaterials and bacterial cellulose, including zero-dimensional nano-units (silica nanospheres, ferroferric oxide microspheres). , carbon black particles, etc.), one-dimensional nano-units (carbon nanotubes, calcium silicate nanowires, silicon carbide wires, etc.), two-dimensional nano-units (boron nitride nanosheets, graphene oxide, nano-clay tablets, etc.). In the prepared bulk material, the nano material content weight ratio is adjustable from 0 to 85%, and the micro nano material can be uniformly distributed in the macroscopic three-dimensional nano cellulose block network.

According to reports, the block prepared by this method can well retain the excellent properties of its nano-scale nano-scale. Among them, the prepared carbon nanotube/bacterial cellulose composite film has better comprehensive performance of electrical conductivity and mechanical strength than all similar materials reported in the past. While maintaining high strength, the electromagnetic shielding performance of this composite film is also superior to the similar materials reported. In addition, the microbial fermentation process under normal temperature and pressure does not use any organic solvent, does not produce and emit any harmful substances, and has the advantages of environmental friendliness and low cost.

Nanomaterials have many excellent properties. The assembly of nanomaterials into macroscopic scale materials can achieve microscopic "integration" of microscopic properties, and have properties not possessed by individual nanoparticles, such as optical, magnetic, electrical and ion conductivity properties. . However, how to assemble nanomaterials into macro-scale materials and maintain their unique properties at the nanometer scale is the key to the practical application of nanomaterials and one of the important challenges.