Effects of compressive strains on electrical conductivities of a macroscale carbon nanotube block

A macroscopic block (∼9mm3) of aligned carbon nanotubes (CNTs) was grown by chemical vapor deposition and its simultaneous electrical conductivity and compressive strain responses were measured parallel and perpendicular to the CNT alignment. The block exhibits elastic moduli of 0.9 and 1.6MPa for compressive strain of <20% in parallel and perpendicular configurations, respectively. The electrical conductivity increases with increasing compressive strain in both configurations. The reversible electrical conductivity and compressive strain responses of block is attributed to elastic bending of CNTs. These excellent properties of CNT block can be used in compressive strain sensing applications.