Application of Spectroscopic Analysis for Plasma Polymerization Deposition onto the Inner Surfaces of Silicone Tubes

Abstract

In the current study, plasma-polymerized methyl methacrylate (PP-MMA) generation on the inner surface of a silicone tube was performed in a capacitively coupled discharge reactor. The possibility of generating plasma inside the tube was analyzed and calculated by using optical emission spectroscopy (OES). A hollow cathode model was first proposed to determine whether plasma discharge would be generated inside the tube in the low-pressure regime. Since the ignition of plasma inside the tube is necessary for the initiation of polymerization processes, the sheath thickness was calculated analytically. To achieve the goal, the electron temperature and density of plasma should be determined beforehand. In this study, the electron temperature and plasma density were measured and calculated according to OES spectra using both the modified Boltzmann plot and the line-ratio method. The results reveal that the occurrence of plasma inside the tube can be achieved if the tube’s inner diameter is greater than two times the thickness of the sheath. The effect of methyl methacrylate (MMA) monomer concentration on sheath thickness, and, hence, plasma generation and deposition, was investigated in the presence of argon plasma and MMA monomer. According to the study, one could control the ignition of plasma discharges inside the tube followed by plasma polymerization deposition. The OES method was also applied to identify the presence of the excited species related to the fragmented monomer. The deposition of PP-MMA films on the inner surface of the tube was confirmed via attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy.

An atmospheric pressure plasma device with multiple ring electrodes for decontamination of flexible tubing with variable scales

“…dis tl 2 dis tl 5 dis tl 3 dis tl 4 dis tl 1 dis tl 6 (11) Therefore, the critical condition of the electrode spacing parameter design model for MSC-RRJ is that under the desired applied voltage, E apply_designed , the effective discharge region length of R 2 (R 5 ) is greater than or equal to 0 mm, as shown below:…”

“…Satoshi used oxygen plasma generated in a narrow tube with a length of 500 mm and a diameter of 4 mm to realize the disinfection of the tube's inner surface under low‐pressure conditions. [ 8 ] The same treatment method has been verified effective to increase the tube's hydrophilicity [ 9 ] and prevent plasticizer leaching [ 10 ] or polymerization deposition [ 11 ] of inner narrow tubes. Discharge plasma for sterilization of narrow tube inner surface, in terms of bactericidal effect, compared with ozone and UV light irradiation, [ 12 ] has more application prospects with a self‐enhanced plasma discharge effect under certain conditions.…”

The Correlation of Plasma Characteristics to the Deposition Rate of Plasma Polymerized Methyl Methacrylate Thin Films in an Inductively Coupled Plasma System

“…By using proper methodology, electron density (n e ), and electron temperature (T e ) could be calculated according to the obtained plasma emission spectra. The detailed approach can be found in Reference [6].…”

“…2, by increasing the Ar/MMA volume ratio from 0.009 to 1, the electron density increases, while the electron temperature decreases. It is known that the Debye length of plasma is proportional to the square root of the electron temperature and inversely proportional to the square root of the electron density [6]. Thus, the Debye length decreases with the increase in argon amount.…”

“…The deposited PP-MMA thin films are known to be highly cross-linked, which derives directly from the fragments of the monomers due to collisions in the plasma. Such a highly cross-linked polymer has several physical and chemical advantages, which include high mechanical stiffness, low porosities, a smooth surface, high stability, good transparency, and even good electrical behaviors [5,6].…”