Academic Commons

Theses Doctoral

Ion conduction characteristics in small diameter carbon nanotubes and their similarities to biological nanochannels

Amiri, Hasti

In this study, we designed a series of experiments to determine the factors governing ion permeation through individual carbon nanotubes (CNTs) less than 1.5 nm in diameter and 20 µm in length. We then rationalize the experimental results by using a model, which is drawn from previous literature on protein ion channels and is centered around a simplified version of the Gouy-Chapman theory of electrical double layer. Lastly, we experimentally demonstrate and discuss the general similarities in ion permeation characteristics between CNTs and biological ion-selective pores. The role of many potential factors influencing the ion transport is assessed by taking two experimental approaches: (1) studying the effect of electrolyte concentration and composition on channel conductance and reversal potential, and (2) examining a second type of nanochannel as a parallel ion conduction pathway within the same device architecture and measurement set-up, which we refer to as leakage devices. This helps to differentiate the effect of CNT on ionic transport from any other possible source. Taken together, these two experimental methods provide strong evidence that the electrostatic potential arising from ionized carboxyl groups at the nanopore entrance has a significant effect on ionic permeation in a manner consistent with a simple electrostatic mechanism.


  • thumnail for Amiri_columbia_0054D_12424.pdf Amiri_columbia_0054D_12424.pdf binary/octet-stream 16.5 MB Download File

More About This Work

Academic Units
Thesis Advisors
Nuckolls, Colin
Ph.D., Columbia University
Published Here
November 26, 2014