Rolling and unrolling of graphene sheets via in situ generation of superparamagnetic iron oxide nanoparticles

This manuscript reports a novel method for the automatic rolling and unrolling of reduced graphene oxide sheets using in situ generated superparamagnetic iron oxide nanoparticles. The graphene oxide synthesized through a low temperature modified hydrothermal method is subjected to hydrothermal reduction to obtain reduced graphene oxide (rGO). The as-prepared rGO was subjected to a second level of hydrothermal reduction in the presence of in situ generated superparamagnetic iron oxide nanoparticles, which led to the formation of graphene nanoscrolls decorated with superparamagnetic iron oxide nanoparticles. The nanoscrolls are unrolled to produce rGO sheets when the iron oxide nanoparticles are washed with hydrochloric acid. The repeatability of nanoscroll formation was examined by repeating the hydrothermal reaction for the in situ generation of superparamagnetic iron oxide nanoparticles in the presence of opened up rGO sheets. This reaction again made the rGO sheets scrolled. A blank reaction was also carried out without iron oxide particles to confirm the necessity of Fe3O4 in nanoscroll formation.