Adsorption of polymers on functionalized organic surfaces

A subject of great interest over the past ten years has been the fundamentals of polymer adsorption on metal oxide surfaces and its relation to polymer-metal adhesion. A few studies dealt with the adsorption of acrylic polymers, such as poly(methyl methacrylate) (PMMA) and poly(acrylic acid) (PAA), on aluminum oxide surfaces [1-4]. In those studies the surface hydroxyl groups have been shown to play an important role in the reaction that results in the bonding of the polymer molecules on the oxide surface. However, in those cases one has little control over the chemistry (i.e. kind of functional groups) and the concentration of functional groups on the solid surface. A surface modification technique that has been developed during the past five years and circumvents this problem, is the adsorption of alkyl thiols on gold surfaces. Alkyl thiols of sufficient hydrocarbon chain length have been shown to form self-assembled well oriented monolayers on gold surfaces with the sulfur atom attached to the surface and the alkyl chain extending outwards. When the thiols are functionalized at the other end of the chain they expose the functional group at the ambient interface creating a surface that is functionalized with the desired group. By mixing alkyl thiols with functionalized alkyl thiols of the same length one can control the density of the functional group on the surface. We are interested in the interactions of polymers with such model surfaces and the effect of surface functionality and density on the conformation of the adsorbed polymer chains.