title: Internal structure of polyelectrolyte multilayers probed via neutral impact collision ion scattering spectroscopy.
abstract: Layering in polyelectrolyte multilayer films has been studied by neutral impact collision ion scattering spectroscopy. The method affords a direct look at vertical ordering within these films at the nanometer scale. By labeling certain polyelectrolyte layers with heavy atom (Ru) probes, sufficient contrast has been obtained to visualize and quantify the distribution of these labeled polyelectrolytes throughout the film. The results indicate that the materials under investigation here produce linear film growth with very limited layer interpenetration. The interdigitation length between neighboring layers within the film is measured as 3.9 nm, which is approximately 1.4 times the thickness of an individual polycation/polyanion pair and is slightly less than the measured air/film roughness (4.7 nm). Detailed analysis shows that under the conditions used and at the depths probed in this study, the observed layer thickness is not significantly broadened by either instrumental or stochastic factors.
authors.affiliation: Department of Chemistry and Biochemistry, Clippinger Laboratories, Ohio University, Athens, OH 45701-2979, USA.
authors.forename: Hazel L
authors.initials: HL
authors.lastname: Tan
authors.forename: Thomas
authors.initials: T
authors.lastname: Krebs
authors.forename: Gunther
authors.initials: G
authors.lastname: Andersson
authors.forename: David
authors.initials: D
authors.lastname: Neff
authors.forename: Michael
authors.initials: M
authors.lastname: Norton
authors.forename: Harald
authors.initials: H
authors.lastname: Morgner
authors.forename: P Gregory
authors.initials: PG
authors.lastname: Van Patten