Analytical characterization of poly(pyrrole-3-carboxylic acid) films electrosynthesised on Pt, Ti and Ti/Al/V substrates

With the aim of developing a polymeric multilayer film for application in advanced biomaterials, as a first step poly(pyrrole-3-carboxylic acid) films (abbreviated as PPy-3-carbox) were electropolymerised from pyrrole-3-carboxylic acid solutions by cyclic voltammetry and chronoamperometry on platinum, titanium and Ti90Al6V4 substrates and characterised both electrochemically (cyclic voltammetry) and spectroscopically (X-Ray Photoelectron Spectroscopy, XPS). Electrochemical experiments showed that the potential range adopted for electropolymerization affects the polymer electroactivity, by analogy with unsubstituted polypyrrole. The combination of conventional and chemical derivation-XPS provided information on PPy-3-carbox surface structure, showing no significant difference between films grown on different substrates and an increase of the COOH groups amount (one group over three pyrrole rings, as an average) with respect to unsubstituted polypyrrole (PPy), as expected. Finally, a preliminary Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) investigation was performed in order to get further information on the polymer structure and electroactivity.