Development Of Super Elastic And Fatigue Resistant Carbon Nanofiber Aerogels

The reporter learned from University of Science & Technology China that the research team of academician Yu Shuhong and Professor Liang Haiwei combined the project with thermal chemical control to transform the structural biomaterial into graphite carbon nanofiber aerogel, which perfectly inherited the macroscopic and microscopic structure of bacterial cellulose, with remarkable thermal mechanical properties and large-scale synthesis. Relevant results were recently published in advanced materials.

　　 Lightweight compressible materials with super elasticity and fatigue resistance are ideal materials for aerospace, mechanical buffering, energy damping and soft robots. Many low density polymer foams are highly compressible, and are prone to fatigue when used repeatedly, and superelastic degradation occurs near the glass transition and melting temperatures of polymers.

Although carbon nanotubes and graphene possess inherent superelasticity and thermal mechanical stability, the complex equipment and preparation process involved can only make millimeter scale materials. On the other hand, the complex hierarchies of biomaterials evolved from hundreds of millions of years in nature have attracted much attention due to their excellent mechanical properties. However, because they are pure organic or organic / inorganic composite structures, they are usually suitable for working in very narrow temperature ranges. Therefore, the transformation of these non thermally stable structural biomaterials into thermal stable graphite materials with inherent hierarchical structure is expected to create thermodynamically stable materials.

The team developed a chemical control method for the pyrolysis of bacterial cellulose using inorganic salts, and achieved a large-scale carbonization process. The carbon nanofiber aerogels successfully inherited the macroscopic and microscopic structure of bacterial cellulose, showing obvious superelasticity and fatigue resistance in a wide temperature range. Because carbon nanofiber aerogels have excellent thermal stability mechanical properties and can achieve macro fabrication, they will have important application prospects in many fields, especially for mechanical buffering, pressure sensing, energy damping and aerospace solar cells under extreme conditions.