ELECTROSTATIC ADSORPTION OF POLYSTYRENE NANOSPHERES ONTO THE SURFACE OF AN ULTRATHIN POLYMER FILM PREPARED BY USING AN ALTERNATE ADSORPTIONTECHNIQUE

We studied the adsorption of polystyrene nanospheres that have anionic charges on their surfaces from their aqueous dispersions onto the sur faces of cationic ultrathin polymer films quantitatively and kinetical ly by using a quartz crystal microbalance (QCM) and scanning electron microscopy(SEM). The polymer films were successively prepared by the a lternate adsorption of poly(allylamine hydrochloride) (PAH) and poly(s odium 4-styrenesulfonate) (PSS) in the absence or presence of suitable NaCl concentrations onto the QCM substrate so that we could observe t heir formation process by its frequency shifts. We observed the specif ic adsorption of the nanospheres by means of electrostatic interaction onto the outermost PAH surface by QCM as well. The dependence of thei r adsorption amounts against the NaCl concentration in polymer precurs or film preparation was a sigmoid curve, indicating that there is a cr itical charge on/in the film for their adsorption. SEM observations sh owed monolayer adsorption without three-dimensional aggregation. We al so studied the effects of particle size on their adsorption behavior a nd the possibility of the multilayering of nanospheres. This research on adsorption behavior by electrostatic interaction will be applied to the adsorption system of not only polymeric nanospheres but also othe r inorganic nanoparticles.