Leaflet-heterostructures by MWCNT self-assembly following electrospinning.

Electrospinning of nanocarbons such as graphene and carbon nanotubes typically produces mats composed of one-dimensional fibers where the carrier polymer encapsulates the nanocarbons. Recently it was found that decreasing the amount of carrier polymer in approaching the electrospinning-electrospray boundary for graphene suspensions resulted in retention of the graphene two-dimensional anisotropy with one-dimensional carrier polymer fibers connecting flakes. We explored a similar decrease in carrier polymer in MWCNT suspensions to investigate the network topology that might ensue. Unexpectedly, two-dimensional leaflet meso-networks were obtained wherein the leaflets comprise laterally aligned MWCNTs one to several nanotubes thick. A mechanism based on capillary force-driven MWCNT self-assembly activated by menisci formed during drying of electrospun fibers is presented. Such materials offer new approaches to producing high surface-area coatings for catalytic and energy applications and suggest ways of formulating two-dimensional MWCNT assemblies in metal foams and other open-cell porous materials.