Graphene oxide auto-cross-links

Sheets of graphene oxide can undergo spontaneous cross-linking reactions, which essentially glue the sheets together, as a result of common drying procedures. The finding broadens scientists’ understanding of basic graphene chemistry and sounds a cautionary note about processing this 2D form of carbon, which is a common starting material for graphene-based products ( Chem 2022, DOI: 10.1016/j.chempr.2022.05.016 ). Graphene oxide (GO) is an inexpensive material easily prepared by oxidizing and exfoliating graphite. The ultrathin sheets are easily dispersed and processed in water and are readily reduced to graphene chemically or via other methods, making GO a convenient reagent from which to make fibers and films for applications in energy storage, electronics, and other areas. The oxidation reaction used for preparing GO leaves the sheets covered with hydroxyl and carboxyl species. Researchers have functionalized those groups, attaching various types of molecules via esterification reactions. “It’s somewhat surprising that no one seems