Roles of chain conformation and interpenetration in the growth of a polyelectrolyte multilayer

In the present study, we have investigated the growth of a multilayer formed by poly(sodiurn 4-styrene sulfonate) (PSSS) and poly(diallyldimethylammonium chloride) (PDDA) at different salt concentrations by use of quartz crystal microbalance with dissipation (QCM-D). The frequency change (Delta f) demonstrates that the exponential growth mode gradually becomes dominant as NaCl concentration (C-NaCl) increases. On the other hand, the dissipation change (AD) reveals that the deposition is dominated by chain conformation at C-NaCl < 1.0 M, where the change of the characteristic growth parameter agrees well with the results fit with Debye length. At C-NaCl >= 1.0 M, the growth is not determined by chain conformation but by chain interpenetration.