Nanosilicas can disperse single-wall
carbon nanotube (SWCNT) in
aqueous solution efficiently; SWCNTs are stably dispersed in aqueous
media for more than 6 months. The SWCNT dispersing solution with nanosilica
can produce highly conductive transparent films which satisfy the
requirements for application to touch panels. Even multiwall carbon
nanotube can be dispersed easily in aqueous solution. The highly stable
dispersion of SWCNTs in the presence of nanosilica is associated with
charge transfer interaction which generates effective charges on the
SWCNT particles, giving rise to electrostatic repulsion between the
SWCNTs in the aqueous solution. Adhesion of charged nanosilicas on
SWCNTs in the aqueous solution and a marked depression of the S<sub>11</sub> peak of optical absorption spectrum of the SWCNT with nanosilicas
suggest charge transfer interaction of nanosilicas with SWCNT. Thus-formed
isolated SWCNTs are fixed on the flexible three-dimensional silica
jelly structure in the aqueous solution, leading to the uniform and
stable dispersion of SWCNTs