Therefore, with an increase in the electric field strength, most interestingly, the counterions do not leave the brush but rather move from the "inside the brush" region to the "brush-bulk interface" region. The presence of these counterions at the brush-bulk interface implies that they are still screening the brush charges (hence the SE remains close to 100%); but more importantly, it leads to a significantly large counterion velocity, given that these counterions are not experiencing the large retardation force that they would have experienced if they were inside the brush layer [see of the Cl -counterions in "inside the brush" region (Cinside denotes the corresponding counterion percentage in "inside the brush" region) and in the "brush-bulk interface" region (Cinterfaces denotes the corresponding counterion percentage inside the "brush-bulk interface" region) with the strength of the applied electric field.