Hyperbranched Molecules with Epoxy-Functionalized Terminal Branches: Grafting to a Solid Surface

Abstract

We report the fabrication of a molecular surface coating from an epoxy-functionalized hyperbranched polyester functionalized by secondary epoxy groups. These groups were presented in the fraction of terminal branches of the hyperbranched shell with the ratio of epoxy-containing branches and alkyl branches of 1:2. We demonstrated that a uniform monolayer with the thickness of 4.5 nm could be fabricated by melt grafting of functionalized hyperbranched polymers to a bare silicon surface. Steric constraints imposed by the chemical attachment of alkyl and epoxydized branches to a single core prevented microphase separation of dissimilar segments and allowed the fabrication of uniform monolayers with surface exposure of the functional groups and high adhesion. An estimated 3−4 epoxy groups per molecule were located in the uppermost surface layer and provided residual functionality sufficient to graft another polymer layer. Grafted layers were extremely robust and sustain high compression and shear stresses whil...