Electroosmotic flow (EOF) is widely used to transport and mix fluids in microfluidic chipsAiming at the parallelplate microchannel with surface roughness
governing equations describing the EOF were established and the influence of surface roughness and electrical double layer (EDL) on EOF was investigated by using finite element method (FEM)The simulation results indicated that
when the EDL thickness was comparable to 0.3 times of the height of surface roughness
the presence of surface roughness could alter EDL near the surface
and reduce the EOF significantlyWhen the EDL thickness was much smaller or much greater than the height of surface roughness
EOF was less affected by surface roughnessThe relationship between the EOF speed in bulk flow region and the relative EDL thickness was “V-shaped”.