Adsorption of a semiflexible wormlike chain

A.N. Semenov

doi:doi:10.1140/epje/i2002-10092-2

EPJ

Adsorption of a semiflexible wormlike chain

A.N. Semenov

semenov@polly.phys.msu.ru

Abstract
Adsorption of ideal polymers with stiff backbone onto a flat surface is considered theoretically. Both scaling approach and quantitative theory are developed. We predict a self-similar monomer concentration profile $c(x)\sim x^{-4/3}$ near the surface (when the distance to the surface x is much smaller than the chain persistence length l/2). The typical conformation of a weakly adsorbed chain can be viewed as a sequence of alternating flat (2-dimensional) trains of wormlike short loops (flat blobs) and coil-like (3-dimensional) loops forming a triple-layer structure: contact layer $(x<\Delta$ ) of adsorbed fragments virtually laid on the surface, proximal layer $(\Delta <x<l$ ) of flat blobs, and more dilute distal corona layer (x>l). Here $\Delta$ defines the range of monomer/surface attraction, $\Delta\ll l$ . The adsorption transition is continuous. However, its relative width $\frac {\Delta T}{T^{*}}$ is small (T^* is the adsorption temperature, $\Delta T$ is the relevant temperature interval): $\frac {\Delta T}{T^{*}}\sim\left(\frac {\Delta}l\right)^{4/3}$ , i.e. a discontinuous transition in the limit $\Delta /l\to 0$ .

PACS

EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2002