Ion drag EHD micropump with single walled carbon nanotube (SWCNT) electrodes

Abstract

Ion drag electrohydrodynamic (EHD) micropumps are promising in a number of micro-scale applications due to its small form factor, low power consumption, ability to work with dielectric heat transfer fluids, good controllability and absence of any moving parts. Ion drag EHD micro-pumps have been studied widely and the pressure head has been reported to depend on electrode material (i.e., work function), geometric configuration, electrode surface topology and applied electric field. One drawback of such pumps is the relatively low pressure head generation and high threshold voltage required for the onset of charge injection for practical applications. The presence of micro/nano features with sharp asperities on the emitter electrodes is likely to enhance the local electric field and charge injection significantly and thus, the pressure generation. The objective of this work is to investigate the effect of surface topology on the charge injection and pressure generation in HFE 7100. Experiments were performed using micropumps with smooth and single wall carbon nanotube (SWCNT) deposited on smooth gold electrodes. A lower threshold voltage, higher charge injection and pressure head was found for the micropump with SWCNT deposited on smooth electrodes compared to the no deposition case.