Growth of a dense polymer brush layer from solution

Abstract

The chemical grafting of alkanethiol-terminated poly(ethylene glycol) to a gold substrate from dimethylformamide solution was monitored by in situ ellipsometry for several molar concentrations. In the initial stage a layer of mushroom-like moieties forms and, on a much longer time scale, is followed by conformational conversion (and further adsorption) to a dense brush of stretched polymers. A statistical mechanical theory is presented that allows for a nonuniform grafting density and conformational conversion. It accounts fully for all observed details.