Graphene microtubings: Controlled fabrication and site-specific functionalization

Manipulating graphene through engineering for macroscopic assemblies of practical importance is a big challenge. We develop a dually geometric confinement approach for the scalable preparation of meter-long graphene microtubings (μGTs) with a tunable diameter. They have strength comparable to graphene fiber and can be shaped to hierarchical multichannel μGT systems in a straightforward way. Of particular importance, μGTs can be selectively functionalized in a site-specific outer-wall, inner-wall, outer/inner-wall, and within-wall fashion, which endows the μGTs with unique properties for desirable applications. Apart from the magnetically and photoelectronically responsive μGTs developed here, a self-powered micromotor made of Pt inner-wall modified μGT showing agile motion in aqueous medium has been also achieved. Beyond the applications demonstrated in this study, the well-defined μGT systems can also play essential role in other important fields such as fluidics, catalysis, purification, separation, and sensing.