Diffusional Response of Layer-by-Layer Assembled Polyelectrolyte Chains to Salt Annealing

Journal Article · Tue Jun 02 04:00:00 EDT 2015 · Macromolecules

DOI:https://doi.org/10.1021/acs.macromol.5b00361· OSTI ID:1426594

Selin, Victor ^[1]; Ankner, John F. ^[2]; Sukhishvili, Svetlana A. ^[1]

---

1. Stevens Inst. of Technology, Hoboken, NJ (United States). Dept. of Chemistry, Chemical Biology and Biomedical Engineering
2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS)

Here, we report on the effect of salt on diffusion of polyelectrolyte (PE) chains within electrostatically assembled polyelectrolyte multilayers. Layer-by-layer (LbL) films were assembled using poly(methacrylic acid) (PMAA) as a polyanion and quaternized poly(2-(dimethylamino)ethyl methacrylate) as a polycation. Fluorescence recovery after photobleaching and neutron reflectometry were used to monitor the center-of-mass diffusion of PMAA chains in directions parallel and perpendicular to the substrate (D_∥ and D_⊥, respectively). Film intermixing and polymer chain diffusion in the direction perpendicular to the substrate exhibit an unusual dependence on the PMAA molecular weight, with dramatically stronger diffusional response to salt annealing for the films formed by PMAA with the lowest molecular weight of 7 kDa. Finally, films assembled with this lowest molecular weight PMAA reveal that both diffusion coefficients of PMAA chains (D_∥ and D_⊥) depend exponentially on the concentration of salt in the annealing solutions, with much faster diffusion in the direction parallel to the substrate.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE; National Science Foundation (NSF)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1426594
• Journal Information: Macromolecules, Journal Name: Macromolecules Journal Issue: 12 Vol. 48; ISSN 0024-9297
• Publisher: American Chemical Society
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
59 BASIC BIOLOGICAL SCIENCES