Observation of carbon nanotube filament bridging induced by gas discharge breakdown between electrodes

Abstract

We have recently found that discharge breakdown between a pair of electrodes, one of which is covered by carbon nanotubes (CNTs), results in the formation of CNT filaments, comprising many short bundles of CNTs and bridging the two electrodes. We have also found that this is triggered by the spark discharge of the ambient gas and is significantly affected by the morphology of the initial CNT film. This phenomenon may provide a suitable method for spinning CNTs, particularly for short CNTs (lengths <100 µm). Here, we examined the formation of CNT filaments in detail to understand the formation mechanism. The voltage required for the filament formation was markedly lowered by reducing the interelectrode distance. A temporal observation showed that the formation is completed within 500 ms from the start of discharge. The filaments after being formed could be elongated by increasing the interelectrode distance. This is favorable for the spinning of CNTs.