skip to main content

DOE PAGESDOE PAGES

Title: Chain Conformation and Dynamics in Spin-Assisted Weak Polyelectrolyte Multilayers

In this paper, we report on the effect of the deposition technique on film layering, stability, and chain mobility in weak polyelectrolyte layer-by-layer (LbL) films. Ellipsometry and neutron reflectometry (NR) showed that shear forces arising during spin-assisted assembly lead to smaller amounts of adsorbed polyelectrolytes within LbL films, result in a higher degree of internal film order, and dramatically improve stability of assemblies in salt solutions as compared to dip-assisted LbL assemblies. The underlying flattening of polyelectrolyte chains in spin-assisted LbL films was also revealed as an increase in ionization degree of the assembled weak polyelectrolytes. As demonstrated by fluorescence recovery after photobleaching (FRAP), strong binding between spin-deposited polyelectrolytes results in a significant slowdown of chain diffusion in salt solutions as compared to dip-deposited films. Moreover, salt-induced chain intermixing in the direction perpendicular to the substrate is largely inhibited in spin-deposited films, resulting in only subdiffusional (<2 Å) chain displacements even after 200 h exposure to 1 M NaCl solutions. Finally, this persistence of polyelectrolyte layering has important ramifications for multistage drug delivery and optical applications of LbL assemblies.
Authors:
 [1] ;  [1] ;  [1] ;  [2] ;  [3] ;  [1]
  1. Stevens Inst. of Technology, Hoboken, NJ (United States). Dept. of Chemistry, Chemical Biology and Biomedical Engineering
  2. Columbia High School, Maplewood, NJ (United States)
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source
Publication Date:
OSTI Identifier:
1324130
Grant/Contract Number:
AC05-00OR22725; DMR-0906474
Type:
Accepted Manuscript
Journal Name:
Langmuir
Additional Journal Information:
Journal Volume: 31; Journal Issue: 13; Journal ID: ISSN 0743-7463
Publisher:
American Chemical Society
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source; Stevens Inst. of Technology, Hoboken, NJ (United States)
Sponsoring Org:
USDOE Office of Science (SC); National Science Foundation (NSF) (United States)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 36 MATERIALS SCIENCE