128. Solving a chemistry problem

The surfactant C12H25(OC2H4)3OSO3Na is adsorbed on the surface of TiO2 pigment particles. Calculate the value of the electrokinetic potential of unmodified and modified particles if the displacement of the sol boundary during the time t=2*103 s during electrophoresis was
Surfactant concentration c*103, kmol/m3 0 0.2
Boundary offset a*102,m 2.5 0.4
Moving the sol to the cathode to the anode
The distance between the electrodes is 25*10-2 m, the voltage applied to the electrodes is 120 V. The dielectric constant of the medium is ε=81; electrical constant ε0=8.85*10-12 f/m; medium viscosity 1*10-3 Ns/m2. What is the observed phenomenon called?