Green, Scalable, Binderless Fabrication of a Single-Walled Carbon Nanotube Nonwoven Fabric Based on an Ancient Japanese Paper Process

We propose a fabrication method for carbon nanotube (CNT) nonwoven fabrics based on an ancient Japanese papermaking process where paper is made from natural plant fibers. In our method, CNT nonwoven fabrics are made by a scalable process of filtering binder-free, aqueous suspensions of CNTs. The aqueous suspension of these entangled single-walled carbon nanotube (SWNT) aggregates enabled smooth filtration through a cellulose filter with large pores (8 mu m). The wet SWNT cakes, which were composed solely of SWNT and water and obtained after filtration, were press-dried to fabricate an SWNT nonwoven fabric. This environmentally friendly process employs water and the raw CNT material alone. Moreover, the scalability of this process was demonstrated by manufacturing a large area (A3, 30 x 42 cm; thickness: 40-150 mu m), self-supporting SWNT nonwoven fabric with a density of 0.4 g/cm(3), a basis weight of 0.2 g/m(2), a porosity of 63%, and a specific surface area of 740 m(2)/g. This SWNT nonwoven fabric is anticipated to find application as functional particle-supported sheets, electrode materials, and filters.