Experimental verification of an equivalent circuit for the characterization of electrothermal micropumps: high pumping velocities induced by the external inductance at driving voltages below 5 V.

摘要: Electrothermal micropumps (ETμPs) use local heating to create conductivity and permittivity gradients in the pump medium. In presence of such gradients, an external AC electric field influences smeared spatial charges bulk When there is also a symmetry break, field-charge interaction results effective volumetric force resulting medium pumping. The advantages ETμP principle are absence moving parts, opportunity passivate all structures, homogeneous pump-channel cross-sections, as well plateaus broad frequency ranges. ETμPs consisted DC-heating element electrodes arranged 1000 μm × 250 60 (length width height) channel. They were processed platinum structures on glass carriers. An equivalent-circuit diagram allowed us model frequency-dependent pumping velocities passivated nonpassivated ETμPs, which measured at conductivities up 1.0 S/m 300 kHz 52 MHz range. temperature distributions within pumps controlled by thermochromic beads. Under resonance conditions, additional inductance induced tenfold pump-velocity increase more than 50 μm/s driving voltages 5 V(rms). A further miniaturization viewed quite feasible.