Selective purification of multiwalled carbon nanotubes by dielectrophoresis within a large array

A prototype device was made to scale up a method for the wet purification of multiwalled carbon nanotubes (MWCNTs). The device consists of a fluid-flow chamber, which facilitates the flow of MWCNT suspensions across a large array of interdigitated electrodes (IDEs). A radio-frequency voltage provides the electric field for dielectrophoresis. Electric parameters of the array were monitored during the running of the process and were observed to reflect the increase of conductance caused by accumulation of MWCNTs. SEM and Raman spectroscopy showed a decrease in the D-band to G-band ratio for the material accumulated on the array.