Electroosmosis in concentrated colloids and the structure of the double electric layer

The existence of a non-solving layer of bound water (NBL) on the hydrophilic surface of SiO2 particles, containing no counterions of the double electric layer (DEL), was demonstrated using the methods of electroosmotic transfer in a model system of monodisperse, nano-sized spherical particles and the method of osmotic pressure based on the equation of state. The thickness of the NBL was also determined. The nature of the NBL led to further consideration of the structure of the DEL. It is proposed that this layer contains a water interlayer between the surface itself and the inner part of the diffuse layer, where the concentration of counterions is very small or equal to zero.