We further probed the natural electrophoretic response of an ungrafted PMETAC chain (confined in a nanochannel) subjected to an electric field of strength 1 V/nm. The details of the system and simulation procedure have been provided in section S8 of the SI. Figs. 6(a) and 6(b) respectively show the snapshots of the system before the application of the electric field and 0.34 ns after the application of the electric field. By comparing these two snapshots (the orange line is the center of the nanochannel), we can see that the PMETAC chain (green) has moved to the right, while Cl -counterion cloud has moved to the left. This confirms that the positively charged ungrafted PMETAC chain moves in the direction of the electric field, i.e., it perfectly follows the expected electrophoretic motion. We can further confirm such electrophoretic response by noting that the velocity of the particles belonging to the chain is positive (i.e., these particles move in the direction of the electric field) and the velocity magnitude of a Cl -counterion is negative (i.e., the Cl -ions move opposite to the direction of the electric field) [see Fig. ].