Surface (XPS, SIMS) chemical investigation on poly(pyrrole-3-acetic acid) films electrosynthesized on Ti and TiAlV substrates for the development of new bioactive substrates

Abstract

Electropolymerization of pyrrole-3-acetic acid was performed by cyclic voltammetry on titanium and Ti90Al6V4 substrates with the aim of developing a multilayer structure for applications in advanced biomaterials. The polymeric films obtained were characterized by both XPS and time-of-flight secondary ion mass spectrometry (ToF-SIMS). Information on the poly(pyrrole-3-acetic acid) (PPy-3-acetic) surface structure was achieved by a detailed XPS analysis of C 1s and N 1s signals. The number of COOH groups was quantified by XPS coupled to a chemical derivatization reaction in which esterification with trifluoroethanol was exploited so that the presence of fluorine (or the CF 3 component in C 1s spectra) could be used as a marker for COOH groups. As a result, it was found that more than 90% of the monomer units along PPy-3-acetic chains bear carboxylic functionalities, of which 60% are protonated and 40% are present as carboxylate groups. Some decarboxylation occurs with film ageing.The PPy-3-acetic films were also investigated by ToF-SIMS in the negative ion mode, thus obtaining, for the first time, interesting information on the structure of the top surface layers of a polymer belonging to the polypyrrole family. In particular, clusters of peaks related to PPy-3-acetic oligomers were detected and the decarboxylation phenomenon on top of the polymer surface was confirmed.

Red to Blue High Electrochromic Contrast and Rapid Switching Poly(3,4-ethylenedioxypyrrole)-Au/Ag Nanocomposite Devices for Smart Windows

“…[27] Our assignments corroborate well with values reported for polypyrroles doped with per- www.chemphyschem.org chlorate ions. [28] The same assignments hold good for the nanocomposite films as well ( Figure 5 b and c). But an additional component observed at % 399.5 eV for the nanocomposites ( Figure 5 b and c) arises from the Ag-N and Au-N (pyrrole ring of PEDOP) interactions, which is in line with a similar higher-energy N1s component due to Au-N interactions, previously reported for a polyaniline-Au composite.…”

ToF‐SIMS study of stages in the electrochemical growth of insulating poly(o‐aminophenol) films

“…In view of further bio‐applications, information on the structure of the top surface layers of the polymer is necessary for anchoring biomolecules, such as peptides, while retaining their ablity to interact with the surrounding biological system. In this context, the combination of time‐of‐flight (ToF)‐SIMS with XPS has proved fruitful in the investigation of complex polymer systems …”

“…In this context, the combination of time-of-flight (ToF)-SIMS with XPS has proved fruitful in the investigation of complex polymer systems. [2] The main advantage of ToF-SIMS over other surface techniques is its capacity to provide high molecular specificity and high sensitivity, which can clarify the chemistry of polymer surfaces and interfaces. [3] When combined with XPS, ToF-SIMS often provides complementary information.…”

Surface Characterization of Electro-Assisted Titanium Implants: A Multi-Technique Approach

“…The presence of halogen-containing species at the surface was confirmed in a successive work, with other important features highlighted by SIMS, such as the presence of silver traces in the electrolytic solution and of oxidized species, likely containing the carboxylic groups of PPy-3-carbox films. TOF-SIMS investigations on 3-pyrrole-acetic electrosynthesied coatings underlined a decarboxylation of the rings and a decrease in unsaturation degree [21].…”