Vapor‐induced spreading dynamics of adsorbed linear and brush‐like macromolecules as observed by environmental SFM: Polymer chain statistics and scaling exponents |
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| Authors: | Marat O. Gallyamov Bernd Tartsch Petra Mela Igor I. Potemkin Sergei S. Sheiko Hans Börner Krzysztof Matyjaszewski Alexei R. Khokhlov Martin Möller |
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| Affiliation: | 1. Faculty of Physics, Lomonosov Moscow State University, Leninskiye gory 1‐2, GSP‐2, 119992 Moscow, Russia;2. Marat O. Gallyamov, Faculty of Physics, Lomonosov Moscow State University, Leninskiye gory 1‐2, GSP‐2, 119992 Moscow, Russia;3. Igor I. Potemkin, Faculty of Physics, Lomonosov Moscow State University, Leninskiye gory 1‐2, GSP‐2, 119992 Moscow, Russia;4. Martin M?ller, Institute of Technical and Macromolecular Chemistry, RWTH Aachen and DWI at the RWTH Aachen e.V., Pauwelsstr. 8, D‐52056 Aachen, Germany;5. Organische Chemie III, Universit?t Ulm, Albert‐Einstein‐Allee 11, D‐89069 Ulm, Germany;6. Institute of Technical and Macromolecular Chemistry, RWTH Aachen and DWI at the RWTH Aachen e.V., Pauwelsstr. 8, D‐52056 Aachen, Germany;7. Polymer Science, Universit?t Ulm, Albert‐Einstein‐Allee 11, D‐89069 Ulm, Germany;8. Department of Chemistry, Campus Box 3290, Venable and Kenan Laboratories, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599‐3290;9. Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213;10. Department of Colloid Chemistry, Max Planck Institute of Colloids and Interfaces, D‐14424 Potsdam‐Golm, Germany |
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| Abstract: | Scaling exponents ν, that describe the correlation between mean square end‐to‐end distances and contour lengths of macromolecules, were determined by statistical analysis of scanning force micrographs of single linear poly(2‐vinylpyridine) and brush‐like poly(butanoate‐ethyl methacrylate)‐graft‐poly(n‐butyl acrylate) macromolecules adsorbed on mica. Using an atmosphere‐controlled scanning force microscope, single adsorbed molecules were collapsed and re‐expanded upon being exposed to alcohol and water vapor, respectively. This manipulated collapse‐unfolding was used to equilibrate the molecular structure/conformation. The in situ and real‐time scanning force microscopy analysis allows the scientist to quantitatively characterize end‐to‐end distances and contour lengths of the molecules directly on the image and to observe differences in the spreading dynamics for the two types of macromolecules. A distinct difference has been observed between the expanded two‐dimensional (2D) conformations of linear and brush‐like polymer chains. Whereas a scaling exponent ν of 0.73 was found for the expanded 2D conformation of the linear molecules, a ν‐value of 0.53 was determined for the expanded 2D conformation of the seemingly stiffer brush‐like molecules. A theoretical explanation of the differences between the 2D conformations of brush‐like and linear macromolecules is proposed here. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 2368–2379, 2007 |
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| Keywords: | atomic force microscopy (AFM) conformational analysis real‐time imaging scaling exponent single macromolecules stimuli‐sensitive polymers surfaces |
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