Imaging axial vs radial solute transport in an extended weak polyelectrolyte brush

Description:
Understanding molecular transport in polymer brushes is crucial for separations, as well as for drug delivery, anti-fouling, and biosensors, where complex structural features of the polymer can control intermolecular interactions. Theoretical studies predict structural heterogeneity in polymer brushes, which is difficult to assess by conventional experiment methods. Here, we use a 3D single molecule tracking method based on phase engineering to understand the transport mechanism in positively charged poly(2-(N, N-dimethylamino)ethyl acrylate) (PDMAEA) brush with an oppositely charged dye, Alexa Fluor 546, as the probe molecule. The additional complexity of the point spread functions (PSFs) in phase engineering methods requires parallel computing to improve the performance of an unbiased 3D tracking algorithm previously developed in our laboratory. Our results demonstrate the spatial heterogeneity in PDMAEA brush and the resulting distribution of confined/unconfined probe diffusion inside. Confined probes present faster axial diffusion than lateral, and unconfined probes hop between chains with more lateral freedom than axial.

Speaker: Christy Landes - Rice University
Christy F. Landes is the Kenneth S. Pitzer-Schlumberger Chair and Professor of Chemistry, Electrical & Computer Engineering, and Chemical & Biomolecular Engineering, and the Director of the Center for Adapting Flaws into Features (CAFF) at Rice University. The Landes Group is comprised of chemists, applied physicists, and engineers who develop next-generation tools to image dynamics at soft interfaces at the limit of a single event. Her group devises new methods and models for controlling macroscale processes such as protein separations and photocatalysis using this super-resolved chemical knowledge. The group also uses advanced signal and image processing methods to improve accuracy and precision in low-signal measurements.