Polymers plasma coating

Schwerzel, R.E. and Spahr, K.B., Hydrogen Production with Photoactive Semiconductor Catalysts Stabilized by Metallized Plasma Polymer Coatings, Final Report to U.S. Department of Energy, Brookhaven National Laboratory, Battelle, 1989. 

Denes, A.R. and Young, R.A. (1999). Reduction of weathering degradation of wood through plasma-polymer coating. Hol orschung, 53(6), 632-640. 

A Perkin-Elmer instrument (TGA 7) was used for the thermal analysis. The heating temperature was varied from 50 to 600°C at a rate of 10°C/min, and air was used as purging gas. These measurements provide information about the weight of the plasma-polymer coating per unit weight of the substrate. 

For measuring the Al-polymer (PP) peel strengths the plasma polymerization was performed using the previously described reactor. Then, the plasma polymer coated polymer samples were transferred into a separate electron beam metallizer (Auto 306, Edwards, UK). The thickness of deposited aluminium layers was adjusted to 150-200 nm using a quartz microbalance. The metal peel-... 

Blattler, T. M. Covalent Immobilization of Poly(L-lysine)-g-poly(ethylene glycol) onto Aldehyde Plasma Polymer Coated Surfaces. Diploma Thesis, University of South Australia, 2004. 

A nanofilm of plasma polymer (up to about 100 nm) has sufficient electrical conductance as evidenced by the fact that an LCVD-coated metal plate can be coated by the electrolytic deposition of paint (E coating), i.e., plasma polymer-coated metals can be used as the cathode of the electrolytic deposition of paint (see Chapter 31). Thus, the plasma polymer layer remains in the same electrical potential of the cathode (within a limited thickness) and the work function for the secondary electron emission does not increase significantly. When the thickness of plasma polymer deposition increases beyond a certain value, the coated metal becomes eventually insulated, and DC discharge cannot be sustained. DC cathodic polymerization is primarily aimed to lay down a nanofilm (10-100 nm) on the metal surface that is used as the cathode (see Chapter 13). 

ESR signals [7] observed with LCVD-coated glass rods are shown in Figures 6.5, and 6.6. By removing plasma polymer coating from the surface of a glass rod, it is possible to quantitatively examine both the free spins in the plasma... 

Considering the fact that the refractive index continues to increase after most of the polymerizable species are exhausted in the gas phase, DC LCVD of TMS in a closed system contains the aspect of LCVT of once-deposited plasma polymer coating by hydrogen luminous gas phase. In the later stage of closed-system LCVD, oligomeric moieties loosely attached to a three-dimensional network are converted to a more stable form, and significantly improved corrosion protection characteristics (compared to the counterpart in flow system polymerization of TMS) were found, details of which are presented in Part IV. Thus, the merit of closed-system cathodic polymerization is well established. 

Due to physical confinement, the relationship between the gap distance and the CDST becomes an important factor when large substrate surfaces are to be treated via the AMT technique. When Ar plasma was used to treat a TMS plasma polymer-coated CRS panel dark blue in color, the resulting multicolored... 

Thus, a tumbler reactor with basket sample holder could be a very efficient and inexpensive means to apply plasma polymer coating to suitable small substrate. 

Contact current, nylon 66, plasma polymer coated brass probe. In nitrogen... 

The application of a nanolayer of an optimal plasma polymer prevents the deterioration nearly completely under no electrical stress (see Fig. 24.11) and reduces significantly under the presence of electrical stress (see Fig. 24.12). This observation suggests that the plasma polymer coating shields existing surface flaws, which could... 

The stress level of 5kV/mm is sufficient to observe the onset of deterioration within the duration of experiment of 3000 h. At this level of stress, the complete breakdown did not occur (except one case), but the decay could be followed as a function of time. In saline solution, 5 out of 8 (62.5%) untreated samples showed the initiation of the deterioration within 1000 h. This value for plasma polymer-coated samples dropped to 2/8 (25.0%) for plasma polymer of methane and 1/8 (12.5%) for plasma polymer of (C2F6 + H2). The same frequency at 3000 h is 100% for untreated samples, 75% for plasma polymer of methane, and 25% for plasma polymer of (C2F6 + H2). 

Yasuda, H. Charlson, E. J. Cahrlson, E. M. EPRI Report, Effect of plasma polymer coating on the insulation breakdown, 1995. 

It has been observed the formation of continuous liquids on high-energy solid surfaces, such as mica, quartz, and silica, when those surfaces are subjected to immersion and emersion in water [13,14]. A continuous film of water on a hydrophilic (i.e., high energy) plasma polymer-coated glass slide moments after it was immersed to a depth of 3 cm in a beaker of DDI water is shown in Figure 26.21A. The water film remained continuous as it receded to the bottom of the plate. After about 2 min the water film front receded to approximately 1 cm from the bottom of the plate, as shown in Figure 26.21B. The presence and stability of a continuous water film can be detected and quantified by the Wilhelmy method [15]. 

Figure 26.21 Pictures of a continuous film of water on a plasma polymer coated glass slide (A) just after wetting and (B) after 2 min of exposure to air. Arrows indicate the region of the continuous water film.

Figure 28.2 Alclad 2024 SO2 Salt Spray Tested Panels (4 Weeks) A—chromate conversion coat with E-coat primer, B—chromate conversion coat with Deft primer, C— plasma polymer coat with E-coat primer total scanned area is 27 cm. ...

Figure 28.5 Penetrant inspection/photographs of chromate conversion coated controls and plasma polymer coated AA 2024-T3 ([2B]).

Parylene N to smooth surface materials has been reported with the application of plasma depositions [13,14]. It was reported that excellent adhesion of Parylene C coating to a cold-rolled steel surface was achieved using plasma polymer coatings, in turn giving rise to corrosion protection of the metal [15]. Another major deficiency of Parylene C is its poor painting properties when paint is applied on a Parylene C film, due to its extremely hydrophobic surface. Because of this, surface modification of Parylene films is necessary to enhance their adhesion performance with spray primers. 

The adhesion of Parylene C coatings to three different DC plasma polymer coated bare 7075-T6 surfaces was examined the results are summarized in Table 30.1. Plasma polymer of TMS/hexafluoroethane (FIFE) showed the best results among the three types of plasma polymers. After exposure to air for around 1 day before deposition of Parylene C, this plasma polymer still showed a very good adhesion to Parylene C coatings. As shown in the table, radio frequency argon... 

LPCAT-CH4 treatment deposits plasma polymer of methane on the substrate surface. Since the energetic species are consumed in building up the layer of plasma polymer, the irradiation eflfects of plasma onto the exposed substrate polymer is much less. The excellent adhesion of a primer to the LPCAT-CH4-treated TPO was interpreted due to the replacement of the weak boundary layer by the interaction of tight network of plasma polymer of methane [23]. Plasma deposition from organic compounds, such as methane and ethane, can produce a thin layer of plasma polymer coating with tight networks. 

It is important to pay attention to the potential role of peroxides created on the surface of plasma-treated, including plasma polymer-coated, TPOs in the formation of durable bonds between the substrate and primer. It has been known for decades that the peroxides formed on the irradiated polymers (by y-ray. X-ray, electron beams, etc.) can be utilized in graft copolymerization of various monomers. This method is known as the peroxide method of radiation copolymerization [27]. The trunk polymer is first irradiated by ionizing radiation in a vacuum or in an inert gas environment. The irradiated polymer is exposed to air or oxygen to convert free radicals to peroxides. Thus created peroxides-containing polymers were used as the initiator of the free radical polymerization of the second monomer. The polymer peroxides are decomposed by heat or by the use of reduction/oxidation accelerator, i.e., peroxides are converted to free radicals. 

Figure 31.14 Polarization resistance of [2A] panels with different chemical pretreatments and TMS plasma polymer-coated surfaces.

In contrast, a significant increase of the Rp values was observed with the application of a thin layer of TMS plasma polymers (about 50 nm) on these chemically treated [2A] surfaces. It was also noted that these TMS plasma polymer-coated [2A] samples have the same level of Rp values as the [2A]CC controls. These results clearly indicate that these plasma polymer coatings have a good corrosion resistance property. 

Plasma polymer-coated [2B] surfaces showed higher polarization resistance than native and chemically cleaned surfaces. Thus, the corrosion resistance of plasma polymer-coated [2B] was much higher than that of the barrier-type oxides formed after chemical cleaning. Also, as is evident from the higher polarization resistance of the plasma polymers, they are good barriers to water, oxygen, and corrosive species, even under an externally applied potential. The Rp values of the... 

Deoxidized surfaces of [7B] with a plasma polymer coating ([7B] (Dox)/T) showed higher polarization resistance than the chemically deoxidized surfaces without a plasma polymer. This indicates that the added corrosion resistance offered by plasma polymer films is much higher than that of the barrier-type oxides, formed after chemical cleaning, alone. As compared to the chromate conversion-coated surfaces ([7B] CQ, the deoxidized and plasma polymer-coated ([7B] (Dox)/T) surfaces showed higher Rp values, suggesting that these surfaces have higher corrosion resistance. 

E-coat stripping. Both plasma-treated panels show excellent corrosion protection performance as compared to the control panels. All [2A] panels with different plasma treatments and plasma polymer coatings, which were corrosion tested in both SO2 and Prohesion salt spray tests, were similarly scanned, and the corrosion width was evaluated by using a scanned image and computer calculation of the corroded area. Figure 31.19 compares the corrosion width obtained by the two methods. 

Figure 31.26 Rp values of AA2024-T3 ([2B]), AA7075-T6 ([7B]), Alclad 2024-T3 ([2A]), and Alclad 7075-T6 ([7A]) panels with different chemical pretreatments and plasma polymer-coated surfaces.

Table 32.4 displays the adhesion test results for different spray primers applied to T/F plasma-treated bare 7075-T6 alloys. The results demonstrate that this special plasma polymer coating gave rise to excellent water-insensitive adhesion of all three spray primers used in this study Turco solution could not delaminate any of the primers over a period of 24h. In addition, up to 6 days aging of T/F plasma coatings in air prior to primer application did not degrade the excellent adhesion performance of the systems. 

Figure 32.11 Polarization resistance of plasma polymer coated Alclad 7075-T6 alloys in 0.5% NaCl and 0.35% (NH4)2S04 aqueous solution.

TMS plasma polymer coated steels were analyzed by SNMS. This analytical technique permitted obtainment of high resolution and quantitative information... 

The effect of interface of steel on the corrosion test result is summarized in Table 33.2. The results found for the panels, which were E-coated without phosphate or plasma polymer coatings, are quite astonishing. A scribe creep of 3.0 mm in a 4-week corrosion test was obtained for an oxide-removed CRS surface (without zinc phosphate nor plasma polymer), which is better than the E-coat on the... 

All experimental data and discussions presented above seem to confirm the validity of the hypothesis that if reducible elements present in the surface state (including the ultrathin layer of plasma polymer) on which a cathodic E-coat is applied, those elements will be subjected to the cathodic reduction during the process of the cathodic E-coat deposition, and a weak boundary or defective spots would be created in the interface of the E-coat and the substrate (plasma polymer-coated steel). The validity of the hypothesis implies that the best result of a cathodic E-coat cannot be realized unless the adverse effect of the cathodic reduction can be minimized. In this context, the presence or absence of oxides is a very important factor in the use of a cathodic E-coat, besides the fact that the presence of oxides... 

Figure 33.15 EIS Bode plots for plasma polymer coated pure iron samples.

In order to study the effect of the aging after atmospheric exposure on the potential at the inner buried interface of plasma polymer-coated iron, two different plasma-pretreated iron samples were used. For each pretreatment, different TMS plasma polymer thicknesses were studied 20, 50, and 70 nm for Ar + H2 plasma pretreatment, 20, 55, and 115nm for O2 plasma pretreatment. The Scanning Kelvin Probe (SKP) data shown in Figure 33.18 for (Ar + H2) plasma-pretreated and O2 plasma-pretreated samples depicts a correlation between the potential at the inner buried interface and the polymer thickness for respective sample. SKP results showed that the plasma polymer effectively inhibits reoxidation of the interface... 

Hydrogen permeation rate of the membrane prior to the plasma polymer coating. 

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