Electrochemical growth of PAH-dendrimers supramolecular films. An integrated experimental-theoretical approach

The electrochemical oxidation of a polyphenylene-based dendrimer containing 96 sp2 carbon atoms (PPD) allows obtaining a more extended conjugated carbon framework, polymer PPD (pPPD), starting from the parent fused-benzene-based PPD. The structure and electronic properties of the polymeric thin film obtained by electrochemical oxidation have been characterized by Near Edge X-Ray Absorption Fine Structure (NEXAFS) spectroscopy. Structural properties of the thin film formed upon electrochemical oxidation of PPD, are characterized by Matrix-Assisted Laser Desorption/Ionization (MALDI-TOF) and Gel-Permeation Chromatography (GPC) measurements. The degree of order of the layers as well as the virtual, and occupied, electronic states are addressed and exploited to obtain information on conjugation and oligomer size within the polymeric pPPD film. The experimental results are compared with DFT, B3LYP/6–31G(d), calculations. The overall results suggest that the thin film formed on the electrode surface is mainly formed by PPD dimer and trimer upon electrochemical oxidation.