Plasma polymer composition

Rochow, E.G. (1951). An Introduction to the Chemistry of Silane. 2nd, ed.. Chapman Hall. London. Rostami, H., Iskandarni, B. and Kamel, I. (1992). Surface modification of Spectra 900 polyethylene fibers using RE-plasma, Polym. Composites 13, 207-212. 

The major use of vinylpyrrohdinone is as a monomer in manufacture of poly(vinylpyrrohdinone) (PVP) homopolymer and in various copolymers, where it frequendy imparts hydrophilic properties. When PVP was first produced, its principal use was as a blood plasma substitute and extender, a use no longer sanctioned. These polymers are used in pharmaceutical and cosmetic appHcations, soft contact lenses, and viscosity index improvers. The monomer serves as a component in radiation-cured polymer compositions, serving as a reactive diluent that reduces viscosity and increases cross-linking rates (see... 

It Is easy to see that the observed etch rates tabulated are Influenced significantly by the resist polymer composition. The aromatic polymers at the top of Table I are clearly most resistant to etching. Curiously, the etch resistance trend Is maintained regardless of plasma type or plasma reactive species, and depends more upon the resist polymer composition or structural formula. 

How the starting molecules are fragmented into activated small fragments depends on the energy level of the plasma and the nature of the monomer molecules. This is a reason why plasma polymers possess different chemical composition when the plasma polymerization is operated at different conditions, such as different monomer flow rate, RF power, and pressure of the reaction chamber, even if the same starting materials are used for the plasma polymerization. 

Quantitative characterization of plasma-polymer films, especially of ultrathin fluorinated carbon plasma polymer films, has been performed by ToF-SIMS to study changes in the surface composition and molecular distribution. CFX films on silicon and polyethylene terephthalate (PET) substrates were exposed to a pulsed Ar/CHF3 plasma by varying the deposition time from 10-90 s.111-113 The results show differences in film growth and CFX cross linking for the silicon and PET substrates.111... 

For the cyclic corrosion test, a layer of acrylosilane polymer coating (10-25 fim thick) was dip-coated onto the plasma-deposited substrates. The coated samples were then subjected to 25 scab cycles. The test results are plotted in Fig. 7. Corrosion performance (as described by the length of scribe creep) was correlated to the wattage used for plasma film deposition. As discussed in the previous section, the chemical structure and properties correlated with the deposition conditions, especially the power level applied. Therefore, atomic compositions for plasma polymers deposited at different power levels were also plotted in Fig. 7.A... 

Friedrich JF, Kuhn G, Mix R, Retzko I, Gerstung V, Weidner S, Schulze R-D, Unger WES (2003) Plasma Polymer Adhesion Promoters to be used for Metal-Polymer Composites. 

For LCVD interface engineering of composite materials, it is considered that the tight three-dimensional network is necessary because of the required structural integrity, i.e., type A plasma polymers are essential for LCVD interface engineering. Low-pressure plasma polymerization is considered ideal for such applications because of the mechanisms of polymerization or material formation. 

The expansive internal stress in a plasma polymer is a characteristic property that should be considered in general plasma polymers and is not found in most conventional polymers. It is important to recognize that the internal stress in a plasma polymer layer exists in as-deposited plasma polymer layer, i.e., the internal stress does not develop when the coated film is exposed to ambient conditions. Because of the vast differences in many characteristics (e.g., modulus and thermal expansion coefficient of two layers of materials), the coated composite materials behave like a bimetal. Of course, the extent of this behavior is largely dependent on the nature of the substrate, particularly its thickness and shape, and also on the thickness of the plasma polymer layer. This aspect may be a crucial factor in some applications of plasma polymers. It is anticipated that the same plasma coating applied on the concave surface has the lower threshold thickness than that applied on a convex surface, and its extent depends on the radius of curvature. 

In general plasma polymerization processes it has been established that the deposition rate and properties of a plasma polymer primarily depend on the value of the normalized energy input parameter WjFM, as described in Chapter 8. In LPCAT polymerization processes, as described in Chapter 16, the deposition rate of a plasma polymer primarily depends on the value of the normalized energy input parameter, which is given by W FM)J FM). In this composite parameter, W is the power input applied to arc column, FM) is the mass flow rate of carrier gas (argon), and FM) is the mass flow rate of monomer that is injected into the cascade arc torch. The quantity of W FM)J FM) can be considered as the energy, which is transported by carrier gas plasma, applied to per mass unit of monomers. 

The chemical composition and the surface structure of perfluoropropene plasma polymers were investigated using XPS. The XPS spectra were obtained only for the medium-sized and the large reactors. In each reactor, three crystal sensors... 

The combined gradual change in the methane-to-argon ratio and increase in discharge power resulted in the formation of a composition-graded film. During this cycle, the deposition rate of the methane plasma polymer decreased whereas that of copper or silver increased. 

The results of tensile lap-shear and chemical composition tests for different process schemes are shown in Tables 21.2-21.4. Metal analyses of the initial plasma coating layer and those of the failed surfaces after tensile lap-shear tests confirm that the failure occurred at the interface between the substrate surface and the bottom of the plasma polymer film. These results show that the intermediate layer provided by grading of the metal content throughout the plasma polymer film can improve the strength between the polymer and metal films. The graded metal-containing plasma polymer film can join a polymer and a metal with strong adhesion, and also reduce... 

Figure 21.9 The proposed seetional model of a eomposition-graded transitional buffering film layered by double-graded proeess A, pure methane plasma polymer layer B, composition-graded layer of methane plasma polymer and metal C, sputtered metal layer with earbon contamination.

Composition-graded composite films of plasma polymer and metal can be controlled to give surfaces capable of being electroplated. 

Surface conditioning by plasma pretreatment with oxygen and hydrogen is a crucial factor in obtaining very strong bonding at the interface between the substrate and composite plasma polymer film as a preplate for metallization. 

The shear strength of coatings metallized by employing composition-graded films is dependent on the extent and strength of chemical bonding between the substrate surface and the plasma polymer film. 

The same plasma polymer deposited in a closed-system reactor has a graded elemental composition with a carbon-rich top surface, and the oligomer content is much lower [10], both of which increase the level of adhesion. The adhesion of the same water-borne primer is excellent and survives 8 h immersion in boiling water. When this surface is treated with O2 plasma, the adhesion does not survive 1 h of boiling, while the dry tape test still remains at the level of 5. The water-sensitivity of adhesion depends on the chemical nature of the top surface as depicted by XPS data shown in Figure 28.12. Water-insensitive tenacious adhesion, coupled with good transport barrier characteristics, provides excellent corrosion protection, as supported by experimental data [1-4], and constitutes the basic principle for the barrier-adhesion approach. 

According to this scheme of plasma polymerization of TMS in a closed system, it is anticipated that the atomic composition of the plasma polymer should continuously change with the plasma polymerization time. Figure 13.21 depicts comparison of XPS cross-section profile of C/Si ratios for plasma polymers deposited in a flow system reactor and that in a closed system reactor. The results clearly show that a closed system plasma polymerization of TMS indeed produces a... 

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