title: Transient 3-Dimensional Orientation of Molecular Ions in an Ordered Polyelectrolyte Membrane.
abstract: Single-molecule fluorescence spectroscopy is employed to reveal 3-dimensional details of the mechanisms underpinning ion transport in a polyelectrolyte thin film possessing polymer-brush nanoscale order. The ability to resolve fluorescence emission over three discrete polarization angles reveals that these ordered materials impart 3-dimensional orientation to charged, diffusing molecules. The experiments, supported by simulations, report global orientation parameters for molecular transport, track dipole angle progressions over time, and identify a unique transport mechanism: translational diffusion with restricted rotation. Generally, realization of this experimental method for translational diffusion in systems exhibiting basic orientation should lend itself to evaluation of transport in a variety of important, ordered, functional materials.
authors.affiliation: Rice University, Houston, Texas 77005.
authors.forename: Carmen
authors.initials: C
authors.lastname: Reznik
authors.affiliation: Rice University, Houston, Texas 77005.
authors.forename: Rosalie
authors.initials: R
authors.lastname: Berg
authors.affiliation: University of Houston, Houston, Texas 77204.
authors.forename: Ed
authors.initials: E
authors.lastname: Foster
authors.affiliation: University of Houston, Houston, Texas 77204.
authors.forename: Rigoberto
authors.initials: R
authors.lastname: Advincula
authors.affiliation: Rice University, Houston, Texas 77005.
authors.forename: Christy F
authors.initials: CF
authors.lastname: Landes
keywords: Diffusion; polymer brush; reorientation; single molecule; spectroscopy