COLL 442 |
| Tsetska Radeva, Viktoria Milkova, and Ivana B. Petkanchin. Institute of Physical Chemistry, Bulgarian Academy of Sciences, Sofia 1113, Bulgaria |
| Electrical properties and structure of polyelectrolyte multilayers prepared by layer-by-layer deposition of poly(sodium 4-styrenesulfonate) (PSS) and poly(diallyldimethylammonium chloride) (PDADMAC) on ellipsoidal b-ferric hydrous oxide particles are examined in situ using electric light scattering method. In the initial nonlinear growth regime, the electro-optical effect is found to increase almost in the same manner as the thickness of the multilayer film. This reveals an increase in the multilayer surface charge due to the nonlinear increase in the polyelectrolyte adsorption. Above five deposition cycles, the electro-optical effect reaches a plateau and the thickness increment per layer becomes constant, thus indicating regular film growth. Evidence is given that the concentration of small residual ions, incorporated into the PSS/PDADMAC film, is negligible. Polarization of counterions, bound near to the surface of the last-adsorbed polyion, is supposed to explain the relaxation of the electro-optical effect in the 103-105 Hz frequency range. |
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Colloidal and Molecular Electro-Optics
Division of Colloid and Surface Chemistry |