One-Pot Preparation of Ferrocene-Functionalized Polymer Brushes on Gold Substrates by Combined Surface-Initiated Atom Transfer Radical Polymerization and Click Chemistry

A gold substrate with surface-grafted ferrocene functional polymer brushes, or Au-g-PFTMA surface [PFTMA = poly(5-ferrocene-triazolyl methacrylate)], was prepared by a combination of surface-initiated atom transfer radical polymerization (SI-ATRP) and click chemistry in one pot, in the presence of 2-azidoethyl methacrylate (AzEMA), ethynyl ferrocene, CuBr catalyst, CuBr2 deactivator, and pentamethyldiethylenetriamine ligand. Thus, SI-ATRP of AzEMA from the Au substrate (the grafting from process) and click chemistry of the ethynyl ferrocene to the azide functional group of AzEMA (the grafting to process) proceeded simultaneously to produce the functional PFTMA brushes on the Au surface. Kinetic studies suggest that the reaction involving simultaneous SI-ATRP and click chemistry is still consistent with a controlled/living process. The composition and physical properties of the modified gold surface were analyzed by X-ray photoelectron spectroscopy, water contact angle measurement, and cyclic voltammetry. The redox-responsive properties of the ferrocene-functionalized polymer brushes on the Au-g-PFTMA surface were demonstrated in the reversible loading unloading step of the beta-cyclodextrin polymer via host guest interaction.