Tuning properties of carbon surfaces functionalized with amino-ended dendron layers by exploring their supramolecular interactions

Abstract

An effective tailoring of carbon surfaces functionalized with a first-generation amino-ended dendrons was achieved by a simple self-assembly strategy. The morphology, as well as the viscoelastic and electrical properties of the modified surfaces were characterized at a micro-nanoscale level, by Cyclic Voltammetry (CV), Electrochemical Impedance Spectroscopy (EIS), Atomic Force Microscopy (AFM) and Kelvin Probe Force Microscopy (KPFM). Thermodynamic parameters of the adsorption were investigated by EIS, studying the blocking properties of the modified surfaces towards the redox conversion of [Fe(CN)6]3−/[Fe(CN)6]4−. AFM images were used to characterize the topography of the modified surfaces and also their viscoelastic properties by the acquisition of phase images. π-π stacking interactions between dendrons and the carbon surface control the aggregation at low coverages, while forces of intermolecular Hydrogen-bond among dendrons appear at high coverages leading to more compact regions. The implications of the amino-ended dendron layer on the electrical properties of the modified surface have been analyzed through KPFM in comparison with nitro-ended dendron films, showing a decrease of the local contact potential difference after the incorporation of molecules having electron-donor (−NH2) functional groups, in contrast with the increase showed for molecules with electron-acceptor (−NO2) ones.