Suspended, straightened carbon nanotube arrays by gel chapping

We report large-scale self-assembly of suspended, straightened, single-walled carbon nanotubes (SWNTs) across regular TiO₂ gel islands. By coating a SWNT network on top of a pool of the TiO₂ colloid and inducing a rapid drying and chapping process, initially curled, random SWNTs can be straightened into aligned arrays and suspended across the island gaps. The suspended SWNT arrays were grafted by semiconducting or metallic nanoparticles, resulting in hybrid structures with tailored and neat morphology, and enhanced photoresponse. We further demonstrate these suspended SWNTs can sustain high speed gas blowing (up to 20 m per second) reversibly for hundreds of cycles, and detect gas velocity by the resistance change.