Abstract

Resin samples prepared by compression molding using a poly(methyl methacrylate) (PMMA) denture base material were exposed to radio-frequency (rf) glow discharges to improve the wettability of the material. Fourier transform infrared (FT-IR) reflectance, X-ray photoelectron spectroscopy (XPS), and contact-angle measurements have been employed to characterize the changes introduced by the glow discharge plasma. FT-IR measurements cannot detect any modification. XPS reveals an increase in the O/C atomic ratio. Contact angles of the plasma-treated samples are always lower when compared with untreated ones. The increased O atomic concentration is attributed to formation of -COH groups on the surface during plasma treatment. The O/C atomic ratio decreases upon heating the samples in vacuum to 100 C for 1-2 min and exposing the samples to liquid CH2 Cl2 for 1-2 min. Exposure to distilled water for prolonged periods causes a slight decrease during the initial 1-20 days but levels off to a constant value up to a period of 60 days. Plasma treatment seems to offer a durable increase in the wettability for these materials left in air or distilled water.

Glow Discharge Resonance

A. B. Stewart
J. Opt. Soc. Am. 45(8) 651-657 (1955)

Helium Level Populations in a Glow Discharge*

William J. Condell
J. Opt. Soc. Am. 50(6) 610-616 (1960)

The Formation of Molecular Helium in a Glow Discharge*

W. D. Parkinson
J. Opt. Soc. Am. 41(9) 619-622 (1951)

Laser-induced optogalvanic signal oscillations in miniature neon glow discharge plasma

V. K. Saini
Appl. Opt. 52(18) 4404-4411 (2013)

Increase in nanosecond laser-induced damage threshold of sapphire windows by means of direct dielectric barrier discharge plasma treatment

Christoph Gerhard, Daniel Tasche, Norbert Munser, and Helene Dyck
Opt. Lett. 42(1) 49-52 (2017)