(204f) Crumpled Graphene Nanosheets and Their Assembly into Crosslinked Networks

In this work, aqueous dispersions of pristine graphene nanosheets were prepared using pyrene derivatives as dispersants. Controllable crumpling of these nanosheets was achieved by rapid evaporation of the dispersions in an industrially scalable spray dryer. Morphological transition of 2D nanosheets to 3D crumpled particles was directly observed by sample collection within the spray dryer. The crumpling mechanism depends on parameters such as nanosheet elasticity and surface chemistry. The particle size and morphology of the products can be tuned by altering the spray drying parameters such as temperature and pressure. Also, the unfolding of the crumpled particles upon rewetting depends on the nanosheet type and the solvent choice. Furthermore, 3D networks of highly crumpled graphene oxide were prepared using a low-temperature sol-gel technique. These networks display a remarkable homogenous porous structure with both chemical and physical crosslinks. The electrical conductivity of these samples is comparable to conductivity values reported for the networks prepared from 2D graphene nanosheets.