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This paper deals with the surface modification of reticulated vitreous carbon (RVC) by dielectric barrier discharge (DBD) for electrodes production. RVC samples were exposed to air-DBD plasma for 5.0 and 10.0 min. Following the treatment, the specimens were characterized by scanning electron microscopy (SEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), contact angle measurements, and electrochemical analyses [cyclic voltammetry (CV)]. The SEM images show an alteration of the RVC surface morphology because of the surface etching during the DBD processing. This finding is in agreement with the enhanced specific electrochemical surface area of RVC electrodes, which is related to an increase of its surface roughness. In addition, a slight increase of the oxygen content on the surface was confirmed by XPS analysis. Therefore, the RVC surface became more hydrophilic as detected by water contact angle measurements. For corroborating this statement, a solid monolithic vitreous carbon was used for this test. An increase in the anodic charge of the RVC electrodes due to the surface oxidation was also observed. Raman spectra showed insignificant changes in the material crystalline structure. [ABSTRACT FROM PUBLISHER]

Plasma processing of carbon fibers (CFs) is aimed to provide better contact and adhesion between individual plies without decrease in the CF mechanical resistance. This paper deals with surface modification of CFs by an atmospheric pressure dielectric barrier discharge (DBD) for enhancing the adhesion between the CF and the polymeric matrix. The scanning electron microscopy of the treated samples revealed many small particles distributed over entire surface of the fiber. These particles are product of the fiber surface etching during the DBD treatment that removes the epoxy layer covering as-received samples. The alteration of the CF surface morphology was also confirmed by the Atomic force microscopy (AFM), which indicated that the CF roughness increased as a result of the plasma treatment. The analysis of the surface chemical composition provided by X-ray photoelectron spectroscopy showed that oxygen and nitrogen atoms are incorporated onto the surface. The polar oxygen groups formed on the surface lead to the increasing of the CF surface energy. The results of interlaminar shear strength test (short beam) of CFs/polypropylene composites demonstrated a greater shear resistance of the composites made with CFs treated by DBD than the one with untreated fibers. Both the increase in surface roughness and the surface oxidation contribute for the enhancement of CF adhesion properties. [ABSTRACT FROM PUBLISHER]