Reinforcing Multi-Wall Carbon Nanotubes by Electron Beam Irradiation

To prepare the samples for Transmission Electron Microscopy (TEM) imaging and Atomic Force Microscopy (AFM) measurements, as-grown carbon nanotubes were dispersed in isopropanol and sonicated using HD2200 homogenizer with a power of 20W for 5 minutes. To characterize the nanotubes by HRTEM, a droplet of the suspension was put on a Cu TEM grid with a lacey C film. Alternatively, we deposited a droplet of the suspension by dielectrophoresis on a Si3N4 membrane with pre-drilled 200 nm to 1 μm wide holes, prepared using photoand electron beamlithography processes. The substrate being compatible for both TEM and AFM, the measurements of the bending modulus have been performed on the same CNTs at each irradiation stage.