Elastic Bounded Diffusion. Dynamics of Ferrocene-Labeled
Poly(ethylene glycol) Chains Terminally Attached to the Outermost
Monolayer of Successively Self-Assembled Monolayers of
Immunoglobulins
posted on 1999-10-23, 00:00authored byAgnès Anne, Christophe Demaille, Jacques Moiroux
A model of elastic bounded diffusion is presented for the quantitative analysis of the dynamics of
redox probes borne by the loose ends of linear and flexible polymeric chains terminally grafted to building
blocks of a self-assembled construction. Experimentally, poly(ethylene glycol) chains bearing a ferrocene probe
were terminally attached at the last one of a series of immunoglobulins monolayers successively self-assembled
on top of a glassy carbon electrode. In cyclic voltammetry, the creation of a concentration gradient provoked
a diffusion-like displacement of the ferrocene probe counterbalanced by the springlike elasticity of the terminally
attached polymeric chain. The morphology and the intensity of the signal depend markedly on the distance
separating the terminal attachment from the electrode surface and on the potential scan rate. The observed
changes are qualitatively and quantitatively justified by the model. Both the diffusion and the elasticity can be
quantitatively characterized.