Argon plasma treatment of polycarbonate: In situ spectroellipsometry study and polymer characterizations

Abstract

The influence of argon plasma on polycarbonate ͑PC͒ was studied in terms of structural changes, reaction mechanisms, and adhesion. In situ ultraviolet-visible ellipsometry reveals formation of a surface layer with a higher refractive index than the untreated polymer. The increase in the refractive index is attributed to polymer densification, which in turn is attributed to crosslinking. However a decrease in the average molecular weight is also observed, and two populations of macromolecules of different sizes are detected by light scattering measurements, revealing a competition between crosslinking and degradation. The reaction mechanisms are investigated using nuclear magnetic resonance and in situ infrared ellipsometry. Degradation is caused by carbonate bond breaking, whereas crosslinking seems to be related to a decrease in methyl groups. In addition, an increase in surface acidity is detected by contact angle measurements and is attributed to photo-Fries rearrangements producing phenolic groups. The adhesion of a 1-m-thick silica layer on PC is evaluated by the microscratch test, and its enhancement by argon plasma pretreatment is analyzed.

Effects of oxygen plasma treatment on the surface of bisphenol A polycarbonate: a study using SIMS, principal component analysis, ellipsometry, XPS and AFM nanoindentation

“…21 Most of the research investigating the gas plasma treatment of BPA-PC claims surface crosslinking to be the dominant process. 29,30,44 It was postulated that if a cross-linked skin is formed on the surface of the polymer, as postulated by some workers, 43 it would appear harder than the untreated BPA-PC. Conversely, if the oxygen plasma induced the formation of LMWM on the surface, it should appear softer than the untreated BPA-PC.…”

Ultra-Low Reflectivity Anti-Reflection Coating on a Plastic Cover Slip in Liquid for He-Ne Laser Light

“…Figure 6a,b shows the measured  and Δ data and the simulated results of the silicon dioxide and Substance-2 films on the silicon wafer substrates. We constructed a Cauchy model for a single layer of the film on the substrate, where the surface roughness determined by the substrate was also neglected because the ion assisted deposition during the coating process decreased the boundary scattering and optical absorption, and stabilized the refraction index of the films [9,10]. For the measurements of the coating materials, the MSE values of the data fitting results are 2.27 and 2.75, respectively.…”

“…This indicates that the double-layer sample immersed in the liquid has very good optical stability. It is possible to speculate that the ion-assisted deposition in the deposition process solidifies the deposited film so that the moisture or water in the environment hardly penetrates the film and changes its refractive index [10,17]. Table 1.…”

The Effect of Ion-Beam Treatment on TiO2Coatings Deposited on Polycarbonate Substrates

“…Since Ar is an inert element, the Ar+ ion-beam bombardment on the polycarbonate surface must have caused chain breaking, such as C-C, C-H and C-O, and cross-linking. The radicals originating from the chain breaking reaction readily recombine because they are not thermodynamically stable [14]. In addition, chemical reactions may have occurred by the introduction of the reactive oxygen gas at the activated polycarbonate surface by the Ar + ion beam irradiation.…”

“…On the other hand, when treated by the Ar + ion-beams mixed with oxygen gas, the unstable radicals generated by the chain breaking can combine with the oxygen and recombine with other radicals. It is known that the chemical reaction between the polymer radicals and the oxygen should create hydrophilic groups, such as -OH, which can be related to the reduction of the contact angle and the change of the surface energy [7,14]. Figure 4 shows the typical surface morphology images obtained from an AFM.…”