Influence of Polycation(PDADMAC) Weight on VerticalDiffusion within Polyelectrolyte Multilayers during Film Formationand Postpreparation Treatment.
- Resource Type
- Article
- Authors
- Soltwedel, Olaf; Nestler, Peter; Neumann, Hans-Georg; Paßvogel, Malte; Köhler, Ralf; Helm, Christiane A.
- Source
- Macromolecules. Oct2012, Vol. 45 Issue 19, p7995-8004. 10p.
- Subject
- *CATIONS
*DIFFUSION
*POLYELECTROLYTES
*MULTILAYERED thin films
*STRAINS & stresses (Mechanics)
*MOLECULAR weights
- Language
- ISSN
- 0024-9297
The internal interfaces of polyelectrolyte multilayersare investigatedwith neutron reflectivity. The films are made from poly(diallyldimethylammonium)(PDADMA), poly(styrenesulfonate) (PSS), and deuterated PSS-d. Eachfilm consists of a protonated and a deuterated block. The internalroughness is smallest next to the film/air interface and increaseswith the number of layer pairs away from the film/air interface untila metastable state is reached. Both the final internal roughness andthe interdiffusion constant increase with the salt concentration inthe deposition solution and with PDADMA polymer weight. The increasedmobility found with high molecular weight PDADMA is attributed toresidual stresses occurring during film formation. The experimentssuggest that PSS and PDADMA move partly as a complex. Postpreparationimmersion in 1 M NaCl salt solutions has little effect if the multilayeris prepared from low salt solution and with high molecular weightPDADMA. However, almost complete intermixing is observed for multilayersprepared from 0.1 M NaCl and with low molecular weight PDADMA (diffusionlength exceeds 30 nm). [ABSTRACT FROM AUTHOR]