Reversible fusion and fission of graphene oxide-based fibers.

Stimuli-responsive fusion and fission are widely observed in both bio-organizations and artificial molecular assemblies. However, the design of a system with structure and property persistence during repeated fusion and fission remains challenging. We show reversible fusion and fission of wet-spun graphene oxide (GO) fibers, in which a number of macroscopic fibers can fuse into a thicker one and can also separate into original individual fibers under stimulation of solvents. The dynamic geometrical deformation of GO fiber shells, caused by solvent evaporation and infiltration, is the key to the reversible fusion-fission cycles. This principle is extended to implement flexible transitions between complex fiber assemblies and the inclusion or expulsion of guest compounds.