Single chain structure in thin polymer films: Corrections to Flory's and Silberberg's hypotheses
| Autor: | J. P. Wittmer, Marcus Müller, Kurt Binder, Albert Johner, A. Cavallo |
|---|---|
| Přispěvatelé: | Institut Charles Sadron (ICS), Université de Strasbourg (UNISTRA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), LEA, MOLSIMU, EST SUPERNET programs, Thin film collaboration |
| Jazyk: | angličtina |
| Rok vydání: | 2005 |
| Předmět: |
FOS: Physical sciences
02 engineering and technology Condensed Matter - Soft Condensed Matter Plateau (mathematics) 01 natural sciences Power law Omega 0103 physical sciences General Materials Science 61.25.Hq 67.70.+n 010306 general physics polymers Monte Carlo simulation Physics Condensed matter physics Form factor (quantum field theory) 021001 nanoscience & nanotechnology Condensed Matter Physics Correlation function (statistical mechanics) thin films [PHYS.COND.CM-GEN]Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other] Excluded volume Exponent Soft Condensed Matter (cond-mat.soft) 0210 nano-technology Structure factor |
| Zdroj: | Journal of Physics: Condensed Matter Journal of Physics: Condensed Matter, IOP Publishing, 2005, 17, pp.1697. ⟨10.1088/0953-8984/17/20/004⟩ |
| ISSN: | 0953-8984 1361-648X |
| DOI: | 10.1088/0953-8984/17/20/004⟩ |
| Popis: | Conformational properties of polymer melts confined between two hard structureless walls are investigated by Monte Carlo simulation of the bond-fluctuation model. Parallel and perpendicular components of chain extension, bond-bond correlation function and structure factor are computed and compared with recent theoretical approaches attempting to go beyond Flory's and Silberberg's hypotheses. We demonstrate that for ultrathin films where the thickness, $H$, is smaller than the excluded volume screening length (blob size), $\xi$, the chain size parallel to the walls diverges logarithmically, $R^2/2N \approx b^2 + c \log(N)$ with $c \sim 1/H$. The corresponding bond-bond correlation function decreases like a power law, $C(s) = d/s^{\omega}$ with $s$ being the curvilinear distance between bonds and $\omega=1$. % Upon increasing the film thickness, $H$, we find -- in contrast to Flory's hypothesis -- the bulk exponent $\omega=3/2$ and, more importantly, an {\em decreasing} $d(H)$ that gives direct evidence for an {\em enhanced} self-interaction of chain segments reflected at the walls. Systematic deviations from the Kratky plateau as a function of $H$ are found for the single chain form factor parallel to the walls in agreement with the {\em non-monotonous} behaviour predicted by theory. This structure in the Kratky plateau might give rise to an erroneous estimation of the chain extension from scattering experiments. For large $H$ the deviations are linear with the wave vector, $q$, but are very weak. In contrast, for ultrathin films, $H Comment: 16 pages, 7 figures. Dedicated to L. Sch\"afer on the occasion of his 60th birthday |
| Databáze: | OpenAIRE |
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