It also improves the electrostatic attraction between oppositely charged polymers. As a result, the adsorption of polyelectrolyte chains is more enhanced and thicker layers are obtained
although the thin layer is favoured by the centrifugal force and air shear force. The surface planarization of the mul-tilayer films is also achieved because the weakly adsorbed
chains are easily eliminated by the air shear force (Lawrence, 1988; Meyerhofer, 1978; Ohara et al., 1989)