Buckling of Aligned Carbon Nanotubes as Stretchable Conductors: A New Manufacturing Strategy
We systematically investigated the interesting electric response of the aligned CNT ribbons under mechanical strain. We found that CNTs slide on a PDMS substrate under tension, but buckle under compression (releasing). Such an irreversible mechanical deformation is responsible for the observed irreversibility in the electric resistance upon the first stretching/releasing. In addition, we found that the resistance of the buckled MWNTs remains constant under mechanical strain, which explains why the resistance of the CNT ribbon did not change for the second and subsequent stretching/releasing. The CNT ribbon based conductors exhibit superior stretchability (>100%), which may find broad applications in stretchable electronics, sensors, solar cells and touch screens, to name just a few.
Perhaps more significantly, the interface-mediated buckling approach reported here provides an alternative to the well-known prestrain-then-buckling approach for fabricating stretchable devices, especially out of aligned nanowires or nanotubes. When combined with tremendous recent progress in nanowire/nanotube alignment and contact printing, this new buckling approach could pave the way for large-scale manufacturing (e.g., roll-to-roll process) of nanowire/nanotube based stretchable electronics.