Damage sensing ability of polymer nanocomposites filled with long, shortened and damaged carbon nanotubes

Carbon nanotubes (CNTs) were aggressively tip-ultrasonicated to produce shortened and damaged carbon nanotubes. High-resolution scanning electron microscopic analysis was performed to measure the dimensions of CNTs. Thermo-gravimetric analysis (TGA) was used to evaluate the damage in the sonicated CNTs. Shortened CNTs, in their pristine form (undamaged), were used for comparison with damaged CNTs. Nanocomposite bars, containing CNTs, were indented using Vickers hardness testing machine to produce sub-surface damage. Change in electrical conductivities were analysed after indentation to understand structural damage in nanocomposites having different types (i.e. damaged, shortened and pristine) of CNTs. Nanocomposites having longer and undamaged CNTs possess higher damage sensing ability as compared to nanocomposites having shortened and damaged CNTs.