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Interactions polymères-membranes: une approche locale

Abstract : We consider the problem of polymer chains tethered by one extremity to a fluid membrane. Our description stands on the recognition that an end-grafted polymer applies a well-defined force to the surface. This (entropic) pressure is very high close to the center of the grafting patch and decays sharply for distances larger than the radius of gyration of the chain. The pressure may be tuned by adjusting different parameters such as solvent quality, macromolecular architecture, or by application of an external field. Under this constraint, the flexible interface deforms with a shape that results from the balance between the entropic pressure and the restoring elastic energy. We show that the deformation has a conic form close to the grafting point, the exact profile depending on the boundary conditions imposed upon the membrane. For many tethered chains, the deformation field induces an interaction potential between the polymers. This potential is attractive for polymers grafted on the same side of a membrane and repulsive for polymers grafted on the opposite side. In the last part of this work, we study the fluctuation spectrum of a decorated bilayer. Integrating out the degrees of freedom of the chains, we show that the bending rigidity of the membrane is increased at length scales larger than the radius of the gyration. At length scales smaller than the polymer size, the membrane is smoothed by a tension-like term.
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Contributor : Thomas Bickel <>
Submitted on : Wednesday, February 12, 2003 - 8:16:15 PM
Last modification on : Friday, January 12, 2018 - 1:13:39 AM
Long-term archiving on: : Monday, September 20, 2010 - 11:27:45 AM

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Thomas Bickel. Interactions polymères-membranes: une approche locale. Biophysique [physics.bio-ph]. Université Louis Pasteur - Strasbourg I, 2001. Français. ⟨tel-00002391v2⟩

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