A novel strategy for the large scale and continuous production of aligned carbon nanotube arrays using millimeter-diameter spheres as growth substrates is reported. The present technique is more productive than the conventional process on flat wafers
because of the higher available growth surface and the good fluidity of the spherical substrates. It can be adapted for the industrial production and application of aligned carbon nanotube arrays with lengths up to millimeter.
By sequential feeding of catalyst materials, it is revealed that the active growth sites are at the bottom of the carbon nanotubes (CNTs), and that catalyst particles are constantly encapsulated into nanotubes from the bottom. This gives a better ins
ight into the mechanism of CNT formation and on ways to control the growth process. CNTs encapsulated with different materials should enable the study of their electronic or magnetic properties, with potential applications as building blocks for nanoelectronics and as fillers in composites for electromagenetic shielding.
