Crumpled Graphene Resists Aggregation

Graphene flakes can be crumpled into balls that resist compression and aggregation, according to work published in ACS Nano by a Northwestern University-led research team (DOI: 10.1021/nn203115u). In principle, graphene and other sheetlike materials are endowed with high surface area, making them attractive for energy storage and other applications. In practice, however, the thin films tend to aggregate in solution and restack in the solid state, greatly reducing the surface area of graphene and making it difficult to process. Jiayan Luo, Hee Dong Jang, Jiaxing Huang, and coworkers found that as aerosol droplets of a graphene suspension evaporate rapidly in a furnace, compressive capillary forces wad the flakes into microscopic balls. Similar to crumpled sheets of paper, the harder the graphene balls are compressed, the stiffer they become. The team also found that the graphene balls remain largely intact and can be redispersed in solution even after subjecting the tiny structures to chemical and heat treatments and pelletizing at high pressure.