Plasma surface composition

This fascinating product will still continue to develop to accommodate new applications, safety, health and environment (SHE) issues, advantages of novel materials like nano-composites, plasma-surface-modified carbon black, development of computer simulation techniques, and finally to develop a cybernetic or thinking tire. 

Brown, J.R., P.J.C. Chappell, Z. Mathys (1991), Plasma surface modification of advanced organic fibers part I. Effects on the mechanical, fracture and ballistic properties of aramid/aramid composites. J. Mater. Sci. 26. 4172 178,... 

Donnet, J.B., Dong, S, Guilman, G., Brcndle, M. (1988). Carbon fibers electrochemical and plasma surface treatment. In Proc. ICCl-U, Interfaces in Polymer. Ceramic and Metal Matrix Composites (H. Ishida cd.), Elsevier Sci. Pub., New York, pp. 35-42. 

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. 

Plasma surface treatment of many polymers, including fabrics, plastics, and composites, often occurs. The production of ultra-thin films via plasma deposition is important in microelectronics, biomaterials, corrosion protection, permeation control, and for adhesion control. Plasma coatings are often on the order of 1 100 nm thick. 

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... 

Until now, little attention has been given to the analysis of ancient copper alloys with LA-ICP-MS. This type of material is usually analyzed with fast or instrumental neutron activation analysis (FNAA or INAA), particle induced X-ray emission (PIXE), X-ray fluorescence (XRF), inductively coupled plasma-atomic emission spectrometry or inductively coupled plasma-atomic absorption spectrometry (ICP-AES or ICP-AAS). Some of these techniques are destructive and involve extensive sample preparation, some measure only surface compositions, and some require access to a cyclotron or a reactor. LA-ICP-MS is riot affected by any of these inconveniences. We propose here an analytical protocol for copper alloys using LA-ICP-MS and present its application to the study of Matisse bronze sculptures. 

Table 1 shows the results for the 0%, 2%, and 5% added CF4 in the oxygen plasma cleaning of the silicon wafers, as well as the effect of APS application on the surface composition. 

Surface composition of the plasma-cleaned and APS-treated silicon surfaces... 

The principal difficulty with the previous approaches to molecular speciation has been less with what was attempted and more with the inability to control the sample surface. A recent study of RF plasma treated surfaces has shown that the surface composition can change on exposure to laboratory air and water vapor (91,92). The development of a sample isolation/ treatment/... 

Abstract. This paper describes the functionalization of surfaces against nonspecific protein adsorption. For surface modification photo-immobilization, y-activation or a RF physical plasma is used which changes the chemical surface composition within the first 10 nm region. The surface chemistry is controlled by the use of Time-of-Flight Secondary Ion Mass Spectrometry and X-ray Photoelectron Spectroscopy. 

Biomaterials are non-viable materials used in medical devices, which are biocompatible with minimal non-specific protein adsorption. This paper describes some functionalization techniques of surfaces against non-specific protein adsorption, such as (1) photo-immobilization, (2) y-activation or a rf plasma modification and (3) a wet-chemical treatment. The modification changes the chemical surface composition within the first 10 nm. 

These surface modifications were performed in "pure" micro-wave (2.45 GHz, "single-mode") or in combined microwave/ radio frequency (2.45 GHz/13.56 MHz, "dual-frequency") plasma. Important systematic changes of the surface composition, wettability, and adhesion of thin metal films were observed for different substrate bias values, and for the different gases. The modified surface-chemical structure is correlated with contact angle hysteresis of water drops this helps to identify which surface characteristics are connected with the wettability heterogeneity and with adhesive bonding properties, and how they are influenced by plasma-surface interactions. 

The surface wettability by water drops has been clearly linked with the concentration of chemically bound nitrogen in the surface. Conversely, measurements of advancing and receding contact angles for water can provide information regarding surface composition. On the other hand, there appears to be little or no direct correlation between water wettability and adhesive strength of evaporated aluminum films. Substantial improvement in adhesion of Ai to many polymers can be achieved by 02 plasma treatment of the polymer surface before metallization. Other workers have shown this to result in chemical linkages between the metal and polymer surface moieties. 

Previous static SIMS analyses have also shown (2) that the plasma treatment may induce fragmentation of the polymer backbone and some homogeneization of the polypropylene surface composition. Figure 6a shows static SIMS spectra obtained on a virgin polypropylene sample and Figure 6b on polypropylene which was treated in a N2 plasma for 7 seconds. 

Arimoto, I., Matsumoto, C., Tanaka, M., Okuhira, K., Saito, H., and Handa, T. (1998), Surface composition regulates clearance from plasma and triolein lipolysis of lipid emulsions, Lipids, 33,773-779. 

Development of methods to determine the real surface composition of plasma facing components and their consequences on sputtering, reflection and chemical reactivity. 

Absorption spectroscopy and laser induced fluorescence (LIF), give access to the concentration of molecules, atoms, and ions in the ground state. LIF is enable to achieve highly spatial and time resolved analyses. This technique is thus particularly suitable to investigate composition changes in the plasma, and obtain spatial or time concentration profiles. Published results in fluorine plasmas using absorption [25-27] and LIF [28-32] mainly concern temperature measurements [25] or the quantification of CFV radicals [26-31] in fluorocarbon-based plasmas and SOx in SF6—02 discharges [32], Recently LIF has been used to measure plasma-surface interaction products [33]. 

An Auger electron survey spectrum of an initial PBTMSS film showed the expected composition of the surface layer, namely C, O, Si, and S as shown in Figure 7, curve A. After the exposure to an oxygen plasma the surface composition of the film was vastly different as shown in the AES survey (Figure 7, curve B). Essentially, only Si and O were present in the surface layer. Moreover, the shift in the AES Si peaks from 92 and 1619 eV to 76 and 1606 eV indicated that the Si was present as SiO as opposed to elemental or organosilicon. Monitoring both Si peaks (labeled as Si (92 eV) and Sio (76 eV) enabled us to follow the growth of the oxide layer as a function of time for the different passivation treatments. 

Table 35.5 Variation of Surface Compositions of Plasma Polymers along a 10-m Coated Tubing...

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