The buckypaper is particularly suitable for the present study because it is comprised solely of CNTs (i.e., no binder or other foreign material), and the fabrication is relatively simple, merely requiring filtration of a SWCNT dispersion. We fabricated a series of buckypapers Selleck NVP-BEZ235 from SWCNT forests of different heights, which are schematically illustrated in Figure 1a. The fabrication process comprises three main steps: (1) synthesis of SWCNT forests of determined length; (2) dispersion of the SWCNTs; and (3) fabrication of the
buckypaper. Figure 1 Schematic representation of fabrication process, SEM images of SWCNT forest, photographs of buckypaper and of dispersion of SWCNT. (a) Schematic representation of the fabrication process of buckypaper comprising SWCNT forest with different heights. SEM images of SWCNT forest with (b) 350-, (c) 700-, and (d) 1,500-μm heights. (e) Photograph of the dispersion of SWNCT. (f) Photograph of the buckypaper obtained after the filtration. buy XL765 SWCNT forests of various lengths were synthesized in a fully automated CVD synthetic system equipped with a telecentric height measurement system using the water-assisted CVD process. A Fe/Al2O3 catalyst-sputtered silicon substrate was inserted into the 1-in. diameter quartz tube reactor (1 atm, 750°C). First, the substrate was exposed to a carrier gas (He, total flow of 1,000 sccm)
containing hydrogen (40%) to form catalytic nanoparticles, and then SWCNTs were synthesized using a C2H4 (100 sccm) carbon feedstock and precisely regulated water vapor (100 to 150 ppm). The SWCNT forest
height was controlled by using the height as feedback Resminostat to the control software to automatically stop when the target height was achieved [32]. In this way, SWCNT forests with precisely regulated heights (350, 700, 1,500 μm) could be synthesized in mass quantities. The uniformity of SWCNT forest heights was verified by scanning electron microscopy (SEM; Figure 1b,c,d) and digital photography (see Additional file 1: Figure S1). Next, dispersions of the series of SWCNT forests of differing heights were prepared. Although conventional dispersion strategies aim to completely disentangle the CNTs into isolated particles, it also results in scission. Our strategy minimizes the scission by suspending the SWCNT agglomerates in a solvent while retaining the entanglement (Yoon et al.: Controlling the balance between exfoliation and damage during dispersion long SWCNTs for advanced composites, unpublished). We selected jet milling as the dispersion method because it has shown to preserve the SWCNT length with minimal scission, and it has also been shown that the resulting materials are suitable to fabricate SWCNT/polymer composite materials of high electrical conductivity (Yoon et al.: Controlling the balance between exfoliation and damage during dispersion long SWCNTs for advanced composites, unpublished) [24, 25, 33].