Manufacturing of Ultra-thin, free-standing CNT membranes

M. Dias Lima
LINTEC of America,
United States

Keywords: free-standing films, nanotubes, nanowires, yarns

Summary:

Carbon nanotube (CNT) films can be used as starting material for a variety of products such as electrically conductive layers, filtering membranes and for manufacturing of fiber and yarns (1) . LINTEC have developed dry and liquid based methods to produce large size, free standing films of CNTs which can have an aligned or random orientation, reaching areal densities as low as 0.2 micro g/cm2 (only 2x of single layer of graphene). Their volumetric density can be as low as 1mg/cm3 (close to air) still with a weight normalize tensile strength greater than high strength steel (2). Using only adhesion based on van de Waals forces, these films readily attached to virtually any solid substrates. After liquid densification, their thickness is less than 50 nm what makes than very flexible and resistant to mechanical fatigue. By modifying its topology, stretchable conductive films capable to reach more than 1000% can be manufactured from these CNT films (3). Perhaps the most interesting application for CNT films is the production of CNT yarns through spinning. For single ply yarns, diameters between 3.5 µm and 150 µm can be easily manufactured. Electrical conductivity up to 160 kS/cm can be achieved by doping. 1. Baughman R.H., et al. Science 297 (2002) 787 2. Lima, M.D., et al. Science 338 (2012) 928 3. Liu, Z.F., et al. Science. 349, (2015) 400