Plasma films, applications

As stated, the capability of plasma deposits to reduce the access of water to corrosion-sensitive surfaces may be an important motivation for their application in corrosion protection. In order to study this property, Kapton polyimide film was selected as the substrate because of its high inherent permeability to water and its ability to resist elevated temperatures. The response of Kapton film overcoated by PPHMDSO to the permeation of water vapor is shown in Fig. 1. Clearly, the presence of the organo-silicone plasma film greatly reduces water permeation. The magnitude of the effect is much enhanced when plasma polymers are produced at high T and p. 

Figure 10.8 Scanned image of the surface of two alloy panels showing adhesion failure caused by the omission of O2 plasma treatment of the substrate prior to plasma film deposition and application of the primer (Deft 44-GN-72 MIL-P-85582 Type I Waterbased Chromated Control Primer), a) Panel after Skydrol LD4 fluid resistance test, which had the O2 plasma treatment prior to film deposition and primer application, b) Panel after scribed wet (24-h immersion in tap water) tape test, which had not been treated with the O2 plasma treatment prior to film deposition and primer application.

Figures 31.23 and 31.24 show typical scanned images of SO2 and Prohesion salt spray-tested [7B] panels, respectively. Visual observation of these images reveals that the plasma-modified panels of [7B] have outperformed both control panels in the SO2 salt spray test. These plasma film combinations were prepared on deoxidized [7B] surfaces without any plasma cleaning pretreatment. Figure 31.23 also shows an image of a panel that had simply been deoxidized prior to the application of E-coat, which performed excellently in the SO2 salt spray test. Figure 31.25 compares the corrosion width obtained by the two methods. The comparisons shown in Figures 31.19, 31.22, and 31.25 indicates that the results obtained by the two methods do not match, partly due to the different duration of tests, and that samples which show good results in one test do not do as well in the other test.

Figure 4. (A) Plasma arc annealing of 4-10 nm gold film on the optical fiber tip using a fusion splicer (B) Transmission spectra before plasma arc application (a), after 1 plasma arc (b) after 10 plasma arcs (c).

Polycarbodiimides have been reported to be useful for fire retarding film applications [7a]. In addition, carbodiimide polymers also find use in electrode plate applications where plasma etching is involved [7b]. More recently. 

Poncin-Epaillard, R, Medard, N. and Souti, J.C. 2000. Reactivity of surface groups attached on a plasma treated poly(propylene) film. Application to a new concept of a chelating membrane. Macromol. Chem. Phvs. 201 212-219. 

Deilmann, M. Thei6, S. Awakowicz, P. (2008). Pulsed microwave plasma polymerization of silicon oxide films Application of efficient permeation barriers on polyethylene terephthalate. Surf Coat Technol, Vol. 202, pp. 1911-1917 Deilmann, M. Halfmann, H. Steves, S. Bibinov, N. Awakowicz, P. (2009). Silicon oxide permeation barrier coating and plasma sterilization of PET bottles and foils. Plasma Process, Polym., Vol. 6, pp. S695-S699... 

The plasma may induce the polymerization of a constituent of the gas phase and so cause deposition of a thin polymeric film, or primer, onto the substrate. Several workers have explored this route for depositing a primer, to which another polymer is subsequently adhered, or for depositing a protective coating directly onto a metal substrate [216-223]. For example, Nichols et al. [217] have deposited polymeric primer films, about 30 nm thick, from glow-discharge polymerization of methane tetrafluoroethylene or tetramethyl-disiloxane onto platinum wires. These primers were then coated with a few-micron-thick layer of either poly(p-xylylene) or poly(chloro-p-xylylene), which are good electrical insulators in thin-film applications provided this coating... 

Optical and electrical properties of plasma deposited films, sometimes unique indeed, as well as the easy of their deposition, at low temperature and low cost, on inexpensive substrates of almost any size and shape, render these materials very attractive for optoelectronic applications. The possibility to tailor optical parameters, such as refractive index and extinction coefficient, and what is particularly important - the ability to adjust parameters of the electronic structure, such as transport p, optical gap, density of localized states, etc., recommend these plasma films as active photoelectric elements, e.g. for solar cells and water splitting cells. 

The deposition of organic films by plasma polymerization is an important application of non-thennal plasmas 1301. Plasma polymers are fonned at the electrodes and the walls of electrical discharges containing organic vapours. Oily products, soft soluble films as well as hard brittle deposits and powders are fonned. The properties of plasma... 

Indirect type, batch or continuous operation for pharmaceuticals such as peniciUin and blood plasma. Expensive. Used on beat-sensitive and readily oxidized materials under Liquids under Liquids under Liquids used on pharmaceuticals and related products which cannot be dried successfuby by other means. Applicable to fine chemicals under Granular solids cial cases such as emulsion-coated films under Granular solids... 

The SNMS instrumentation that has been most extensively applied and evaluated has been of the electron-gas type, combining ion bombardment by a separate ion beam and by direct plasma-ion bombardment, coupled with postionization by a low-pressure RF plasma. The direct bombardment electron-gas SNMS (or SNMSd) adds a distinctly different capability to the arsenal of thin-film analytical techniques, providing not only matrbe-independent quantitation, but also the excellent depth resolution available from low-energy sputterii. It is from the application of SNMSd that most of the illustrations below are selected. Little is lost in this restriction, since applications of SNMS using the separate bombardment option have been very limited to date. 

Another illustrative example of the application of FTIR spectroscopy to problems of interest in adhesion science is provided by the work of Taylor and Boerio on plasma polymerized silica-like films as primers for structural adhesive bonding [15]. Mostly these films have been deposited in a microwave reactor using hexamethyldisiloxane (HMDSO) as monomer and oxygen as the carrier gas. Transmission FTIR spectra of HMDSO monomer were characterized by strong... 

Many applications of XPS to problems in adhesion science have been reported in the literature. One interesting example is provided by the work of Tsai et al. on the use of XPS to investigate reactions between model rubber compound and plasma polymerized acetylene films that was discussed above [22,23], Consideration of that system permits some interesting comparisons to be made regarding the type of information that can be obtained from RAIR and XPS. 

Gas plasma treatment operates at low pressure and relatively low temperature. While the corona treatment is applicable to substrates in sheet or film form, the gas plasma process can treat objects of virtually any shape. The gases most widely used to generate plasma by free-radical reactions include air, argon, helium, nitrogen, and oxygen. All these, with the exception of oxygen. 

Direct-current sputtering is not generally applicable for the preparation of thin-film solid electrolytes since these compounds are electronic insulators. The target surface would be charged with the same polarity as that of the ions in the plasma, and the sputtering plasma would rapidly break down. 

Plasma CVD tends to create undesirable compressive stresses in the deposit particularly at the lower frequencies. This may not be a problem in very thin films used in semiconductor applications, but in thicker films typical of metallurgical applications, the process is conducive to spalling and cracking. 

Kato, T., Ito, T., Ishikawa, H., and Maeda, M., Magnetron-Plasma C VD System and its Applications to Aluminum Film Deposit on, Proc. Int. Conf. on Solid State Devices and Materials, Business Center for Academic Societies, Tokyo, Japan (Aug. 1986)... 

Despite such limitations, plasma-deposited a-C(N) H films were found to be used in a number of applications. The stress reduction induced by nitrogen incorporation [12] and consequent adhesion improvement, allowed the development of a-C(N) H antireflective coatings for Ge-based infrared detectors [13]. It was also found that N can electronically dope a-C H films, and can strongly decrease the defect density, which gives prospects on its use as a semiconductor material [14]. Nitrogen incorporation was also found to decrease the threshold electric field in electron-field emission process [15], making possible the use of a-C(N) H films as an overcoat on emission tips in flat-panel display devices [16]. 

Sample preparation for the common desorption/ionisation (DI) methods varies greatly. Films of solid inorganic or organic samples may be analysed with DI mass spectrometry, but sample preparation as a solution for LSIMS and FAB is far more common. The sample molecules are dissolved in a low-vapour-pressure liquid solvent - usually glycerol or nitrobenzyl alcohol. Other solvents have also been used for more specialised applications. Key requirements for the solvent matrix are sample solubility, low solvent volatility and muted acid - base or redox reactivity. In FAB and LSIMS, the special art of sample preparation in the selection of a solvent matrix, and then manipulation of the mass spectral data afterwards to minimise its contribution, still predominates. Incident particles in FAB and LSIMS are generated in filament ionisation sources or plasma discharge sources. 

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