Electro-osmosis
The motion of a liquid containing mobile ions through a porous biological membrane or microchannel driven by an applied electric field.
Governing formula
v_eo = (ε_r ε₀ ζ / η) E (Smoluchowski Equation)
SI unit
m/s (Electro-osmotic Velocity)
In depth
Biological membrane pore walls carry fixed electric charges, forming an electrical double layer (EDL) in solution. Applying an electric field accelerates mobile counter-ions in the EDL, dragging bulk fluid through micro-pores.
Examples in the real world
Microfluidic 'lab-on-a-chip' devices driving precise nanoliter blood sample transport without mechanical pumps.