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8334544 
Meetings & Symposia 
Gated chemical transport and enhance flow through carbon nanotube membranes 
Majumder, M; Chopra, N; Hinds, BJ 
2006 
Boston, MA 
2006 NSTI Nanotechnology Conference and Trade Show - NSTI Nanotech 2006 Technical Proceedings 
1 
106-109 
English 
A promising architecture for ion-channel mimetics is a composite membrane structure containing vertically aligned carbon nanotubes, with inner core diameters of 7 nm, passing across a polystyrene matrix film. Plasma oxidation during the fabrication process introduces carboxylic acid groups on the CNT tips that are modified using carbodiimide mediated coupling between carboxylic acid on the CNTs and accessible amine groups of the functional molecule. Relative selectivity of the permeates was seen to vary from 1.9 to 3.6 as a function of tip-functionalization chemistry. Anionic charged functional groups are seen to sharply increase flux of cationic permeates. Biologically active desthiobiotin was also shown to be reversibly coordinated to stretavidin, showing a reduction in ionic flux through CNT. Pressure driven flux of a variety of solvents (H2O, hexane, decane ethanol, methanol) are 4-5 orders of magnitude than conventional Newtonian flow. There are also experimental indications of the ordering of polar solvents inside CNT pores. Dual functional CNTs (that is different functionality at each end of a CNT) have also been produced by reacting each side of the membrane with different functional solution, then subsequent removal of polymer matrix. 
Carbon nanotube; Chemical separations; Drug delivery; Fluid flow; Membrane