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Poly tetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF) and polyvinyl fluoride (PVF) polymer surfaces were exposed to a remote N 2 or O 2 r.f. plasma. The effect of the plasma power and treatment time on the surface energy and the surface composition were studied by static water contact angle (WCA) and X-ray photoelectron spectroscopy (XPS). In every case, a strong defluorination of the surface was observed. Except for PTFE treated by oxygen, all the surfaces became more hydrophilic after plasma treatment, owing to the grafting of polar nitrogen or oxygen functions. The kinetics of defluorination and grafting seems to be favoured for PVDF and PVF surfaces.

Thin sulfonated polystyrene films were prepared by high pressure PECVD of styrene and trifluoromethane sulfonic acid using a DBD. Argon or helium was used as carrier gas. The chemical composition of the pp‐sulfonated polystyrene was investigated by XPS, SSIMS, and FTIR. XPS shows that the content in sulfonated groups of the films deposited in the discharge can be tuned by varying the temperature of the acid monomer or by improving the HF voltage. Therefore, the films obtained are rich in ionizable groups (more than Nafion). TOF‐SSIMS and FTIR spectra allow to confirm the presence of sulfonic groups (observed on S2p XPS spectra) grafted in the polystyrene matrix.

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An easy procedure to build up membrane-electrode assemblies for applications dedicated to miniaturized PEMFC using H2 or CH3OH by a two-steps atmospheric plasma process is reported. Firstly, catalyst nanoparticles are grafted on carbon substrates by spraying a Pt colloidal solution in the post-discharge of an RF atmospheric plasma torch. In the second step, the resulting decorated electrodes are covered by plasma synthesized polymeric membranes in the discharge of a DBD. The sulfonated polystyrene membranes are synthesized by injecting simultaneously styrene and trifluoromethanesulfonic acid monomers, in the presence of a carrier gas (Ar or He). The membranes are chemically characterized by XPS, ToF-SIMS, and FTIR (IRRAS) and their deposition rate is investigated by SEM.

This feature article is focused on the application of secondary ion mass spectrometry (time-offlight SIMS) to the chemical and structural study of plasma-treated organic surfaces and plasma polymer films. After a brief historical perspective and a presentation of the recent developments of SIMS, illustrative case studies involving plasma-treated polymer surfaces and plasma polymers are presented. Beyond surface analysis by static SIMS, we show the potential of molecular depth-profiling by low-energy Cs þ ions and large Ar n þ clusters for the in-depth chemical characterization of plasma-modified samples. Together with SIMS data processing by multivariate analysis, molecular depth-profiling could provide a step change for the analysis of films treated or polymerized with plasmas.

An organometallic powder (platinum (II) acetylacetonate) is decomposed in the post-discharge of an atmospheric RF plasma torch to deposit Pt nanoparticles on carbon black supports. The resulting nanohybrid materials are characterized by FEG-SEM and XPS techniques to highlight their high content in Pt, their oxidation degree, and the dispersion of the Pt nanoparticles on the substrate. ICP-MS and electrochemical characterizations in a single fuel cell (cyclic voltammetry, dynamic polarization curves) are also performed on electrodes realized by treating the powder mixture overlaid on gas diffusion layers. The comparison of the catalytic activity and the Pt loading with commercially available electrodes shows the great potential of this simple innovative, fast, and robust deposition method.

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