and 180° indicate vertical alignment with the water tail (hydrogen atoms) or water head (oxygen atom) pointing towards the surface respectively. In the pure water system, we observe that the water dipole moment in the first and second interfacial water layers tends to align parallel with the surface, with most water dipole angles in the first layer falling within the range of 60° to 135° and none oriented perpendicular to the surface: this finding is consistent with previous studies . Upon charging the surface and increasing ionic concentration, the water molecules in the first layer reorient themselves. On negatively charged surfaces, the angles range from 30° to 90°, while on positively charged surfaces, the range is from 80° to 150°. This means that the hydrogen/oxygen atoms in the first layer always face towards the negatively/positively charged surfaces, respectively. The results are consistent across concentrations.