universidade de são paulo - Faculdade de Odontologia - Unesp

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fluorine into the surfaces. Fluorine incorporation was confirmed by photoelectron
spectroscopy analysis (XPS), carried out in a UNI-SPECS UHV spectrometer
using Mg K line (E = 1253.6 eV) and with the analyzer pass energy set to 10 eV.
The inelastic background of the C 1s, F 1s, O 1s, and N 1s electron core-level
spectra was subtracted using Shirley’s method. The binding energies of the
spectra were corrected using the hydrocarbon component of the polymer fixed at
285.0 eV. The composition of the surface layer was determined from the ratio of
the relative peak areas corrected by sensitivity factors of the corresponding
elements. The spectra were fitted without placing constraints using multiple Voigt
profiles. The width at half maximum (FWHM) varied between 1.6 and 2.0 eV and
the accuracy of the peak positions was ±0.1 eV. One specimen of untreated
denture base acrylic resin and one of ArSF 6 -treated specimen were analyzed.
Plasma treatments were performed by the application of radiofrequency
power (13.56 MHz) to two parallel plate electrodes fitted inside a homemade
stainless steel vacuum chamber. In this technique, gas temperature remains at
room temperature, preserving the integrity of the material 23,24 . In addition, during
plasma treatment, specific active agents such as, ultraviolet photons and radicals
are generated, resulting in sterilization of the samples 25 .
Contact Angle Measurements
The water contact angle has been measured to characterize the surface
wettability 3,15 . This angle is defined as the angle at the intercept of a plane
tangent to the drop and the plane containing the substrate-liquid interface. The