As a type of thin film,two dimensional(2D) reticulate architectures built of freestanding single-walled carbon nanotube(SWCNT) bundles are suitable for scalable integration into devices and nanocomposites for many applications.The superior properties of these films,such as optical transparency,unique electrical properties and mechanical flexibility,result not only from the outstanding properties of individual SWCNTs but also from the collective behavior of the individual tubes,with additional properties arising from the tube-tube interactions.In this review,the synthesis,structure and fundamental properties,such as conductivity,transparency,optical nonlinearity and mechanical performance,of "freestanding SWCNT bundle network" thin films and nanocomposites,as well as their application as supercapacitors are highlighted.Some long-standing problems and topics warranting further investigation in the near future are addressed.
Field emission from single-walled carbon nanotube （SWNT） nonwoven has been investigated under high vacuum with different vacuum gaps, A low turn-on electric field of 1.05 V/μm is required to reach an emission current density of 10μA/cm^2. An emission current density of 10 mA/cm^2 is obtained at an operating electric field of 1.88V/μm. No current saturation is found even at an emission current of 5 mA. With the vacuum gap increasing from 1 to 10 mm, the turn-on field decreases monotonically from 1.21 to 0.68 V/μm, while the field amplification is augmented. The good field-emission behaviour is ascribed to the combined effects of the intrinsic field emission of SWNT and the waved topography of the nonwoven.
