The Adsorbed Amount Mechanism

The adsorbed amount between the dipping and the spinning methods is significantly different [113]. This is caused by different adsorption mechanisms. Fast elimination of water in the spinning process significantly increased the molar concentration of the polyelectrolyte solution during the short deposition time [129] and this increases in the polyelectroyte concentration yields of thick layers, despite the thin film formation typically provided by the centrifugal force and air shear force [130-132]. It also increases the electrostatic attraction between oppositely charged polymers because the presence of water molecules in the assemblies generally screens the electrostatic attraction. When water molecules are adsorbed onto the substrate, the preadsorbed water molecules may block polyelectrolyte adsorption onto the surface, and thus the surface coverage with polyelectrolyte chains may be incomplete. However, if polymer adsorption and water drainage are almost simultaneously realized in a short time, as in the case of the spin SA process, there would be more room for polyelectrolyte to adsorb onto the substrate.

0 0

Post a comment