Single-Molecule Tracking of Polymer Surface Diffusion

The dynamics of polymers adsorbed to a solid surface are important in thin-film formation, adhesion phenomena, and biosensing applications, but they are still poorly understood. Here we present tracking data that follow the dynamics of isolated poly­(ethylene glycol) chains adsorbed at a hydrophobic...

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Bibliographic Details
Published in:Journal of the American Chemical Society 2014-01, Vol.136 (4), p.1327-1332
Main Authors: Skaug, Michael J, Mabry, Joshua N, Schwartz, Daniel K
Format: Article
Language:English
Subjects:
Adsorption
Diffusion
Kinetics
Polyethylene Glycols - chemistry
Surface Properties
Thermodynamics
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Summary:The dynamics of polymers adsorbed to a solid surface are important in thin-film formation, adhesion phenomena, and biosensing applications, but they are still poorly understood. Here we present tracking data that follow the dynamics of isolated poly­(ethylene glycol) chains adsorbed at a hydrophobic solid–liquid interface. We found that molecules moved on the surface via a continuous-time random walk mechanism, where periods of immobilization were punctuated by desorption-mediated jumps. The dependence of the surface mobility on molecular weight (2, 5, 10, 20, and 40 kg/mol were investigated) suggested that surface-adsorbed polymers maintained effectively three-dimensional surface conformations. These results indicate that polymer surface diffusion, rather than occurring in the two dimensions of the interface, is dominated by a three-dimensional mechanism that leads to large surface displacements and significant bulk–surface coupling.
ISSN:0002-7863
1520-5126
DOI:10.1021/ja407396v