Alignment dependent mechanical responses of carbon nanotubes to light

The authors report the orientation dependent elastic responses of carbon nanotubes to infrared photons. Unaligned and partially aligned samples of single wall carbon nanotubes (SWCNTs) and multiwall carbon nanotubes (MWCNTs) were studied for orientation dependent mechanical responses. While partial alignment in MWCNT ensembles changed the mechanical response to photons from expansion to contraction, the speeds of photomechanical responses were increased at least an order of magnitude by nanotube partial alignment in both SWCNT and MCWNT samples. The unique alignment dependent reversible photomechanical responses of carbon nanotubes are critical for actuator applications.