Finite-stretching corrections to the Milner-Witten-Cates theory for polymer brushes
Department of Mathematics, University of Reading, Whiteknights, Reading, RG6 6AX, UK
Published online: 6 June 2007
This paper investigates finite-stretching corrections to the classical Milner-Witten-Cates theory for semi-dilute polymer brushes in a good solvent. The dominant correction to the free energy originates from an entropic repulsion caused by the impenetrability of the grafting surface, which produces a depletion of segments extending a distance μ∝L-1 from the substrate, where L is the classical brush height. The next most important correction is associated with the translational entropy of the chain ends, which creates the well-known tail where a small population of chains extend beyond the classical brush height by a distance ξ∝L-1/3. The validity of these corrections is confirmed by quantitative comparison with numerical self-consistent field theory.
PACS: 68.47.Pe Langmuir-Blodgett films on solids; polymers on surfaces; biological molecules on surfaces – / 61.41.+e Polymers, elastomers, and plastics –
© EDP Sciences/Società Italiana di Fisica/Springer-Verlag, 2007