Electrodeposition involves three steps: electrophoresis, the transportion of the charged particles to the electrode surface; electrolysis, the gain or loss of electrons at the electrode; and
electroendosmosis, the precipitation and squeezing out of the solvent from the film.
Moisture is driven into paint films by thermal gradients (cold steel, warn on the coating side); by normal hot/cold, wet/dry weathering; by hydrophilic components (salt, solvents, etc.) in the film or on the steel; or by electrical gradients such as
electroendosmosis. Since all paint films are moisture permeable, it makes sense to design the film to avoid blistering and delamination from the inevitable passage of moisture into the film.
Many factors (e.g., variability in gel conductivity, quality of carrier ampholytes, and
electroendosmosis) make IEF inherently difficult to standardize.