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Published on: November 5, 2014
Voltage gated carbon nanotube membranes
Mainak Majumder1, Xin Zhan, Rodney Andrews
1Department of Chemical & Materials Engineering, University of Kentucky, Lexington, Kentucky 40506-0046, USA.
Langmuir : the ACS Journal of Surfaces and Colloids
|July 10, 2007
Summary
This study demonstrates voltage-gated control of ion transport in carbon nanotube membranes using charged molecular tethers. This innovation mimics biological ion channels for robust, large-area applications.
Area of Science:
- Materials Science
- Nanotechnology
- Electrochemistry
Background:
- Carbon nanotubes (CNTs) offer unique properties for transport phenomena.
- Controlling ion flux through CNTs is crucial for applications like sensing and separation.
- Existing methods for functionalizing CNTs can be limited in density and specificity.
Purpose of the Study:
- To develop voltage-gated control of ionic transport in CNT membranes.
- To enhance functionalization density using electrochemical grafting.
- To mimic the function of biological ion channels in a synthetic platform.
Main Methods:
- Fabrication of membranes with aligned carbon nanotubes.
- Electrochemical grafting of diazonium salts to functionalize CNTs.
- Utilizing fast fluid flow during functionalization to direct molecule placement.
- Applying electrical bias to study ion flux and selectivity.
Main Results:
- Achieved voltage-gated control of ionic transport through CNT cores.
- Substantially increased functional density via electrochemical grafting.
- Demonstrated high selectivity (up to 23) between different ions (Ru(bpy)3^2+ and methyl viologen^2+) at -130 mV bias.
- Supported a model of electrostatically actuated tethers inducing steric hindrance.
Conclusions:
- Electrostatically actuated molecular tethers within CNTs can effectively gate ionic transport.
- This approach provides a robust, large-area platform for voltage-controlled ion channels.
- The method offers a promising route for artificial ion channel development.
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Overview