TEM and SEM images of DWCNT and schematic diagram of functionalized anionic dye. (A) TEM image of DWCNTs (purchased from Sigma-Aldrich). (B) SEM image of as-made DWCNT membrane in the cross-sectional view. (C) Schematic diagram of functionalized anionic dye on the CNT tip playing as gatekeeper (gray, C; red, O; blue, N; yellow, S).
Zhan et al. Nanoscale Research Letters 2013 8:279 doi:10.1186/1556-276X-8-279