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Eingeladener Vortrag
- nein (120)
NEXAFS analysis of a plasma treated, partially crystalline poly(ehtylene terephtalate) surface
(1996)
Elastomeric sealants may contain organic silicon compounds. The use of these sealants for housings for electronic components is harmful for the reliability of electric contacts inside. In order to prevent electronic components from malfunction, quality control of elastomeric sealants is required. An analytical procedure developed to fulfil this requirement was developed. It is based on electron spectroscopy for chemical analysis (ESCA). Information on the silicon compounds existing at the surface of elastomeric sealants is provided by this method. Silicon in organic and inorganic compounds can be differentiated with the help of Si 2p photoelectron spectra. Quantitative results can be obtained too. The uncertainty budget of the quantitative procedure is estimated.
Results of the inter-laboratory comparison "Determination of nanometric step heights with AFM"
(2002)
Non-destructive chemical depth-profiling of plasma polymers by variable excitation energy XPS
(2003)
Self-assembled octadecyltrichlorosilane (CH3(CH2)17SiCl3, OTS) films were deposited on an oxidized silicon wafer. They were carefully exposed to a low-pressure oxygen direct current (dc) plasma and/or Cr vapor. Subsequently, they were characterized by X-ray photoelectron spectroscopy, near-edge X-ray absorption fine structure spectroscopy, and atomic force microscopy. Detailed information on the oxygen functionalization and the molecular conformation of the OTS films was obtained. The main result was that functionalization conditions can be found where the order of the film remains almost unaffected. Similarly, Cr evaporation of pure OTS films revealed only slight effects on the order in the film. Cr evaporation of an ordered but functionalized OTS film immediately changes its state toward a fully isotropic one. In the course of interaction, oxygen sites at the surface of the functionalized OTS film are reduced whereas Cr becomes oxidized. A redox reaction scheme is proposed for this interfacial reaction. Finally, it is concluded that the given study should be of importance for advanced plasma processing of polyolefins.
Organic thin films with defined chemical structures and physical properties are required for various applications. Plasma polymerization is of technological interest, since the deposition of plasma polymers is possible on any material of any shape in the desired thickness. We report on the TOF-SIMS (TOF: time-of-flight) and XPS investigations of pulse plasma poly(acetylene) and alkali metal doped pulse plasma poly(acetylene) films. The combination of TOF-SIMS and XPS supplies detailed information on the surface chemistry of these films. Application of both methods provides the possibility for cross-checking certain results. Moreover the different sensitivities of the methods can be utilized. According to the TOF-SIMS and XPS data it can be concluded that the interaction of alkali metals with plasma poly(acetylene) results in electrovalent bonds of the type Me?+C?- between carbon and metal. Furthermore carbonoxygenmetal interactions were observed. These interactions are of the type C=O?-cdots, three dots, centeredMe?+ and/or CO?-Me?+.
Zusammenfassung
Some methods of nano-scale analysis are on the threshold of being a standard method in industry and therefore quality assurance becomes important. But, at the present time, there are deficits in standardisation and validation of these methods. Therefore, we have organised method comparisons and interlaboratory comparisons to overcome these deficits. We report the results of an interlaboratory comparison in step-height determination by atomic force microscopy and the development of a reference material for laterally resolving methods of material analysis.
Pure and PDMS contaminated PS oligomers films were investigated both by time-of-flight static secondary ion mass spectrometry (TOF-SSIMS) and X-ray photoelectron spectroscopy (XPS).
The secondary ion spectra from the PDMS contaminated PS oligomers were almost completely related to PDMS. XPS revealed a PDMS contamination characterized by a silicon surface concentration of 6 at.%. Obviously siloxane contaminants existing on the surface of a silicon wafer may diffuse towards the PS oligomers outermost surface resulting in a rather high PDMS surface concentration of about 85%. Due to the known differences in the information depth and sensitivity of SSIMS and XPS very different detection limits are to be considered.
In elimination of siloxane contaminants by ultrasonication in hexane was found to be an effective way. Another common organic cleaning procedure, which is ultrasonication in trichloroethylene (TCE), subsequently in isopropanol and finally in acetone was found to be ineffective for cleaning of PDMS contaminated silicon wafers.
Barrier properties of plasma and chemically fluorinated polypropylene and polyethyleneterephthalate
(1995)
The functionalization, perfluorination or an coating of polypropylene (PP) and polyethyleneterephthalate (PET) surfaces in different plasma atmospheres and in an F[2] + N[2] gas mixture were investigated. The aim of this work was to form a barrier layer against solvent and fuel permeation. Typical test solvents were n-pentane, toluene, tetrachloroethylene and mixtures of n-pentane and methanol. The permeation was gravimetrically measured. The permeation of the solvent mixtures was analyzed by mass spectrometry and Fourier transform IR spectroscopy. The permeation of the solvent mixtures through the plasma-modified polymer samples was associated with increased absorption of polar solvent components in the polymer film. The thickness of the plasma-fluorinated PP surface layer was 10-100 nm and that of chemically fluorinated PP about 5000 nm. Nearly the same barrier efficiency was measured for both plasma- and chemically fluorinated samples.
Neues vom Urkilogramm
(1999)
Overlayers of SiO2 (nominally 4, 6 and 8 nm thick) on silicon, prepared by thermal oxidation, were investigated using x-ray photoelectron spectroscopy (XPS). The thickness of these overlayers was obtained from a measurement of the photoelectron intensities originating from the substrate and the oxide overlayer by applying an appropriate quantitative model. The uncertainty budget of that thickness measurement method is given. The relative combined standard uncertainty of the method was found to be 15%. The effective attenuation lengths or the corresponding electron inelastic mean free paths are of considerable importance for both the estimated values of overlayer thickness and combined standard uncertainties. The XPS results were compared with ellipsometry data.
Results of an interlaboratory comparison of XPS data obtained with stainless steel are presented. Only one photoelectron spectrometer model was used. The stainless-steel sample surfaces were analysed in different states by XPS: as received, after sputtering to I(C 1s)/I(Fe 2p3/2) 0.025 and after removing a chromium-enriched oxide layer following a certain protocol. The Fe, Cr and Ni elemental concentrations were evaluated from the respective XPS data submitted by the participants of the interlaboratory test experiment. Total means, repeat standard deviations (sr) and reproducibility standard deviations (sR) are presented. The best reproducibility standard deviations were obtained for the XPS analysis after removal of a chromium-enriched oxide layer and quantification of the XPS intensities without taking the contamination elements of carbon and oxygen into account. The absolute reproducibility standard deviation of the elemental concentrations in that case is as small as 1.1-1.5 at.%. This gives 2%, 6% and 16% for the relative reproducibility standard deviation of the concentrations of iron, chromium and nickel, respectively. The total means of the iron, chromium and nickel concentrations finally obtained agree within 2sR with bulk values determined by wavelength-dispersive x-ray fluorescence spectroscopy. Comparison to an earlier interlaboratory test experiment shows that using only one model of photoelectron spectrometer reduces the reproducibility standard deviations efficiently. Copyright © 2002 John Wiley & Sons, Ltd.
Die offenporige Struktur des Holzes und dessen chemische Zusammensetzung bieten sich an, über Tränkverfahren geeignete Precursoren so an den inneren Oberflächen des Holzes zu fixieren, dass bei anschließender thermischer Behandlung ein umweltfreundlicher anorganisch-organischer Verbundwerkstoff entsteht. Aus der Literatur sind hierzu verschiedene Ansätze bekannt. - Ziel der vorliegenden Arbeit sind Verbesserungen der biologischen Beständigkeit, der Feuchtebeständigkeit unter Beibehaltung bzw. leichter Verbesserung der mechanischen Eigenschaften des Holzes. Dies wird durch eine chemische Verbindung (Haftung) zwischen den verbundbildenden Phasen Holz und Precursor und eventuell zusätzlichen Einbau von funktionellen organischen Gruppen realisiert. Als Precursoren dienen über den Sol-Gel Weg hergestellte Kieselsole, die nach vollständiger thermischer Umsetzung zu rein anorganischen Phasen (SiO2) führen. Die Sol-Gel Synthese konnte so optimiert werden, dass durch die Behandlung eine homogene Beschichtung aller Oberflächen erreicht werden kann.
Powder x-ray diffraction (XRD) defined -Al2O3 has been investigated by x-ray photoelectron spectroscopy (XPS) and x-ray excited Auger electron spectroscopy (XAES). The Au 4f7/2 orbital is used for static charge referencing. This feature originates from well-defined and chemically inert 20 nm highly dispersed gold particles deposited on the sample surface. The particles, with a narrow particle size distribution, were obtained from a highly purified colloidal solution (sodium concentration below 1 mg/l). This procedure allows a determination of gold-referenced XPS and XAES data sets. ©2001 American Vacuum Society.
Several approaches were investigated to produce monosort functionalized polymer surfaces with a high density and homogeneity of functional groups: (i) Plasma oxidation followed by wet-chemical reduction, (ii) formation of radicals and grafting on of functional group carrying molecules, (iii) plasma bromination followed by (iv) Williamson or Gabriel-like synthesis of spacer molecules, and (v) a pulsed plasma polymerization of functional groups bearing monomers or (vi) their copolymerisation with other comonomers. The formation of hydroxyl (OH), primary amino (NH2), and carboxyl (COOH) groups was studied in detail. The oxygen plasma treatment (i) in a low-pressure non-isothermal glow discharge results in the formation of a wide variety of O functional groups, polymer degradation and crosslinking. Low power densities and short exposure times (0.1 to 2 s) are required to functionalize a surface while preserving the original polymer structure. Carbonate, ester, and aromatic groups are rapidly degraded by an oxygen plasma treatment leading to scissions of polymer backbones and loss in molecular weight. Also the formation of macrocycles and C=C bonds was observed in a region of around 4 nm in depth. The investigated polymers could be classified by their degradation behaviour on exposure to the oxygen plasma.___TAGSTART___BR___TAGEND___ In order to maximize the process selectivity for OH groups, the variety of oxygen functionalities formed by the oxygen plasma was wet-chemically reduced by diborane, vitridetrade (Na complex), and LiAlH4. Typical yields were 9 to 14 OH groups per 100 carbon atoms.___TAGSTART___BR___TAGEND___ Plasma bromination (iii) (40 Br per 100 C atoms) of polymers, followed by grafting of spacer molecules (iv), has been proved to be a highly selective reaction.___TAGSTART___BR___TAGEND___ Another way to produce high densities of monosort functionalities was the pulsed plasma polymerization of functional group bearing monomers such as allylamine, allylalcohol or acrylic acid (v). The retention of chemical structure and functional groups during plasma polymerization was achieved by using low power densities and the pulsed plasma technique. The maximum yields were 30 OH, 18 NH2, and 24 COOH groups per 100 C atoms. To vary the density of functional groups a chemical copolymerization with ''chain-extending'' comonomers such as butadiene and ethylene was initiated in the pulsed plasma (vi). Additionally, the often-observed post-plasma oxidations of such layers initiated by reaction of trapped radicals with oxygen from the air were successfully suppressed by using NO gas as radical quencher.
This new functionalization method consists of the deposition of very thin plasma polymer layers (20 to 100 nm) of functional group bearing monomers in pulsed plasma. With allylalcohol, a maximum of 30 OH groups per 100 C atoms was measured with a selectivity of about 90% and a significant stability at long-time exposure to air. Allylamine was used to produce primary amino groups, with a maximum of 18 NH2 groups per 100 C atoms. Side reactions were observed during the storage in air, such as oxidation of the amino groups. Carboxylic groups could be produced using acrylic acid with a maximum concentration of 24 COOH groups per 100 C atoms. The most prominent side reaction was the decarbonylation/ decarboxylation of the acid group during plasma deposition.___TAGSTART___BR___TAGEND___ The variation of the density of functional groups using the pulsed-plasma polymerization of functional-group-bearing monomers was possible by the chemically-initiated radical copolymerization with either a chain-extending monomer, such as ethylene, or a cross linker, such as butadiene, in plasma. The density of functional groups could be adjusted continuously (0 to 30 OH, 0 to 18 NH2 and 0 to 24 COOH groups per 100 C atoms).___TAGSTART___BR___TAGEND___ The successful application of these densely functionalized polymer surfaces for producing biocompatible surfaces and for use in metalpolymer composites is proposed.
Cr3+-doped MgF2 systems are synthesised by a novel non-aqueous soft chemistry route using different Cr precursors and varying Cr loading. These systems have been characterized by X-ray powder diffraction (XRD), BET surface area, TPD of ammonia, FT-IR pyridine adsorption analysis and X-ray photoelectron spectroscopy, and tested for their catalytic activity in dismutation of CCl2F2 and CF3CHClF. Catalysts synthesised starting from CrO3 or (CH3CO2)7Cr3(OH)2 showed better catalytic activity than those prepared with CrCl3. FT-IR pyridine adsorption studies reveal that the catalytic activity is highly correlated with the Lewis acid strength. In TPD of NH3 catalysts prepared from CrO3 and (CH3CO2)7Cr3(OH)2, precursors showed a similar behaviour, different from that of catalysts prepared from CrCl3.
etracyano-p-quinodimethane (TCNQ) molecules encapsulated single-walled carbon nanotubes (SWNTs) were investigated by using core level and valence band x-ray photoemission spectroscopy as well as near-edge x-ray-absorption fine structure spectroscopy. The pi-band and pi*-band structures in these molecular systems were investigated, and it was clearly confirmed that a charge transfer occurred in TCNQ-doped SWNTs. TCNQ molecules were negatively charged as to be expected. A depletion of the pi-band density of states of the SWNTs caused by the charge transfer to the TCNQ molecules was observed.
Es wird gezeigt, dass mit einer Kombination der Oberflächenanalyseverfahren ESCA, ToF- SIMS und XAS eine erfolgreiche chemische Charakterisierung von Plasmapolymerfilmen erreicht werden kann. Es werden Elemente und Bindungstypen identifiziert und (semi-)quantitativ bestimmt. Eine Korrelation zwischen Abscheidebedingungen und chemischen Eigenschaften der Plasmapolymerschichten kann hergestellt werden; eine kontrollierte Abscheidung wird damit möglich. Alterungsprozesse, die als Folge einer Atmosphärenexposition auftreten, können beobachtet werden. Die direkte Verbindung der Analysetechniken mit einem Plasmareaktor ermöglicht es, die Alterungsphänomene der Schichten systematisch mit Bezug auf eine frisch abgeschiedene und keinerlei Atomsphäre ausgesetzte Plasmapolymerschicht zu studieren.
Die Verfahrensweise wird exemplarisch am Beispiel von Ethylen-, Allylamin- und Allylalkohol-Plasmapolymerschichten demonstriert.
The dismutation of CCl2F2 was used to probe the effect of halogenation of chromia by Cl/F exchange reactions to find out the difference between the halogenated inactive and active catalysts. The heterogeneous reactions were performed in a continuous flow Ni reactor and also under simulated reaction conditions in a reactor where after the reaction X-ray photoelectron spectroscopy (XPS) and X-ray excited Auger electron spectroscopy (XAES) analyses are possible without air exposure of the catalyst, i.e., under so-called "in situ" conditions. The Cr(III) 2p XP spectra, which revealed multiplet splitting features and satellite emission, were used for chemical analysis by using a simple evaluation procedure which neglects this inherent complexity. Chemical analysis was also applied by using chemical state plots for Cr 3s in order to cross-check Cr 2p related results. Both ex and in situ XPS show that as soon as Cr2O3 is exposed to CCl2F2 at 390°C fluorination as well as chlorination takes place at the catalyst surface. When the XPS surface composition reaches approximately 4 at. % fluorination and 6 at. % chlorination, maximum catalytic activity was obtained. Application of longer reaction times did not change significantly the obtained surface composition of the activated chromia. The fluorination and chlorination of chromia was further investigated by various HF and HCl treatments. The activated chromia samples and the Cr2O3, Cr(OH)3, CrF2OH, CrF3·H2O, α-CrF3, β-CrF3, and CrCl3 reference samples with well-known chemical structures were also characterized by X-ray absorption near edge structure (XANES), time-of-flight secondary ion mass spectroscopy (TOF-SIMS), pyridine-FTIR, wet chemical (F and Cl) analysis, X-ray powder diffraction (XRD), and surface area (BET) analysis. The results suggest that the formation of chromium oxide chloride fluoride species, e.g., chromium oxide halides, at the surface is sufficient to provide catalytic activity. The presence of any CrF3 and/or CrCl3 phases on the activated chromia samples was not found.
Cr3+-doped MgF2 systems are synthesised by a novel non-aqueous soft chemistry route using different Cr precursors and varying Cr loading. These systems have been characterized by X-ray powder diffraction (XRD), BET surface area, TPD of ammonia, FT-IR pyridine adsorption analysis and X-ray photoelectron spectroscopy, and tested for their catalytic activity in dismutation of CCl2F2 and CF3CHClF. Catalysts synthesised starting from CrO3 or (CH3CO2)7Cr3(OH)2 showed better catalytic activity than those prepared with CrCl3. FT-IR pyridine adsorption studies reveal that the catalytic activity is highly correlated with the Lewis acid strength. In TPD of NH3 catalysts prepared from CrO3 and (CH3CO2)7Cr3(OH)2, precursors showed a similar behaviour, different from that of catalysts prepared from CrCl3.
The effect of the composite plasma parameter P/F, where P is the plasma power and F is the monomer flow rate, on the chemical character of pulsed plasma deposited allyl alcohol films was investigated by ToF-SSIMS. Information on the unsaturated character, the cross-linked and/or branched character of the plasma polymer films was derived in detail. The problem of the retention of OH groups in plasma deposited allyl alcohol films was elucidated in detail using SSIMS data. The lowest conversion rate from the monomer's hydroxyl groups to other oxygen functionalities in the plasma was concluded for the plasma polymer film produced at a P/F ratio of 0.05 W · sccm-1. It was found that the overall oxygen content of the films decreased vs. increasing P/F ratio. Because the freshly prepared films were investigated without air exposure, ageing on ambient air could be studied in detail. It was found that in the case of plasma deposited allyl alcohol films the ageing on air is probably based on two competing processes which are discussed in detail. Additionally, a review of literature data on the characterization of plasma deposited allyl alcohol films is given.
Plasma-deposited polymer films were prepared from organic molecules and investigated using near edge X-ray absorption fine structure (NEXAFS) and X-ray photoelectron spectroscopy (XPS) for aging effects after exposure to air. Results from the investigation of homopolymers are summarized. Primarily the effect of the deposition parameters duty cycle and power are dealt with. The effect of the deposition parameter pressure is briefly discussed. An example to show the effect of feed gas composition on the aging of plasma polymerized ethylene/allyl alcohol and styrene/allyl alcohol copolymer is also given. In general, change in content of unsaturated or aromatic species, change in concentration of monomer functionality, and change in the oxygen content was observed in the plasma polymerized films on aging.
XPS and NEXAFS spectroscopy were used for the chemical characterization of pulsed plasma-deposited ethylene films before and after exposure to ambient air. The influence of external plasma parameters on the spectroscopic results was investigated. Information on the chemical character of the plasma-polymerized films, such as the regularity of the primary structure, the amount of long-living radicals, and branching or cross-linking or both was derived from this data. Irregularity and radical concentration for post-plasma reactions of the plasma-deposited films increased with the duty cycle or power. A decreased level of monomer fragmentation and, consequently, an increase in regularity is partially concluded from the experimental data when the monomer pressure is increased. The concentration of surface radicals available for post-plasma reactions also increased with monomer pressure. The correlation found between the degree of the post-plasma oxygen incorporation and the variation of the various external parameters agreed with earlier ToF-SSIMS findings.
Scanning transmission X-ray microscopy (STXM) of h-bar preparations of chemically modified DLC films
(2004)
The formation of plasma-deposited materials made from organic molecules is a technologically attractive way to obtain films with unique properties, e.g. adhesion, wettability, conductivity or selected chemical functionalization. A detailed chemical characterization of these films is a great challenge for the analyst because of the co-existence of a large number of chemical species in plasma-deposited films. We investigated these types of organic films using photoelectron spectroscopy for chemical analysis (ESCA, XPS), near edge X-ray absorption fine structure (NEXAFS) spectroscopy at synchrotron radiation source BESSY II and time-of-flight secondary ion mass spectroscopy (ToF-SIMS). A dedicated plasma preparation chamber was designed and added to the main analysis chamber of the respective spectrometers. This approach offers the possibility of studying plasma-deposited films without exposure to air before analysis (often called in-situ analysis) and the influence of post-plasma reactions, i.e. the ageing process. The present investigations are aimed at finding correlations between basic chemical properties of the deposited films and the plasma deposition parameters, e.g. duty cycle in pulsed plasmas and the power of discharge.
Plasma deposited allylamine films were studied by in situ ToF-SSIMS, XPS and NEXAFS Spectroscopy before exposure to ambient air. The influence of external plasma parameters such as duty cycle, plasma power, and monomer flow rate on (i) unsaturation, (ii) branching and cross-linking, (iii) nitrogen surface concentration and (iv) retention of amino groups was investigated. Harder plasma conditions, which can be obtained when high duty cycles, high plasma power, and low monomer flow rates are employed, increase the unsaturated, branched and cross-linked character of the plasma deposited films, while the surface concentration of N as well as the retention of the monomer's amino group decrease. As proven by NEXAFS findings and cross-checked by ToF-SSIMS results, the allylamine monomer's primary amino groups are partially transformed into other nitrogen functionalities during its plasma polymerization. Amongst them imines and nitriles are the conversion products with the highest probabilities of formation. Another conversion channel is the formation of nitrogen species not participating in the film growth. This is the reason for an increased N loss in plasma deposited allylamine films as observed independently by XPS and ToF-SSIMS when the plasma parameters are changed from mild to hard.
Ageing studies of plasma deposited organic films by surface chemical analysis (ESCA, ToF-SIMS, XAS)
(2006)
Static ToF-SIMS analysis of plasma chemically deposited ethylene/allyl alcohol co-polymer films
(2006)
A plasma co-polymerization of ethylene as a chain extending monomer and allyl alcohol as a carrier monomer for hydroxyl groups was studied. The composition of the feed gas was systematically varied and the plasma co-polymers were analyzed in terms of their relative concentrations of OH functional groups by static Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS) immediately after their preparation without any air contact, i.e., under so called in situ conditions.
The relative OH group concentration involved in the CH2OH groups was derived from the normalized yields of the CH3O+ secondary fragment ion. The density of functional groups in the plasma co-polymers was found to vary non-linearly with respect to the mole percentage of the monomers in the feed gas.
Co-polymerization phenomena, i.e. chemical interactions and recombination reactions taking place between monomer molecules in the plasma and/or during the deposition process, become evident in ToF-SIMS spectra.
Chemical properties of plasma-polymerized styrene films can be effectively controlled by the appropriate choice of external plasma parameters, such as duty cycle, power and monomer pressure. Chemical properties here are the regularity of the primary structure, the amount of long living radicals and branching or cross-linking or both in plasma polymerized styrene films, which can be indirectly monitored by X-ray photoelectron spectroscopy (XPS) and near edge X-ray absorption fine structure (NEXAFS) spectroscopy. Principally, XPS and NEXAFS spectra of plasma-polymerized styrene show all the spectroscopic fingerprints characteristic of atactic polystyrene indicating an inherent similarity of the respective primary chemical structures. There is an increase in irregularity and radical concentration for the plasma deposited films with increasing duty cycle or power. With an increase in monomer pressure, a decreased level of monomer fragmentation and, consequently, an increase in regularity must be concluded from the experimental data. The applied power regulates the fragmentation of the monomers as monitored by spectroscopic signals correlated to the aromatic rings. A trend in the extent of the post-plasma oxygen incorporation according to the variation of the various external plasma parameters was deduced, which agrees with earlier ToF-SIMS findings
Pulsed-plasma-deposited ethylene films were studied by time-of-flight static secondary ion mass spectrometry (ToF-SSIMS) before and after exposure to ambient air. The influence of the external plasma parameters on the secondary ion mass spectra of plasma-deposited ethylene films was investigated. From these data, information on the chemical character of the plasma-deposited ethylene films was derived. The investigation of the effect of external plasma parameters on the chemical character of the plasma-deposited ethylene films revealed that there were some drastic changes in the secondary ion mass spectra of the films. It was found that fragmentation and re-arrangement of the monomer molecules in the plasma, which affects the chemical character of the deposited films, vary according to the external plasma parameters. When the plasma polymers are exposed to air, extensive oxygen incorporation occurs. The oxygen uptake is high at the beginning and then it levels of. Some indications for the formation and decay of peroxy radicals (COO) and, subsequently, hydroperoxides (COOH) are found. It was observed that the oxygen uptake of the plasma deposited ethylene films increase when the plasma conditions become harder.
Analysis of carbon materials by X-ray photoelectron spectroscopy and X-ray absorption spectroscopy
(2003)
Since hard coating such as ta:C films are of growing interest for protecting surfaces of industrial machines and high capacity tools against wear and friction or for biomedical applications, more information about the structure-to-property relation is required. Therefore, core level X-ray photoelectron sprectroscopy and X-ray absorption spectroscopy and spectromicroscopy are used to derive chemical information about selected carbon species.
Selected FTIR, XPS and NEXAFS spectroscopy results obtained with films deposited with different plasma polymerization processes and different monomers (styrene, acetylene, ethylene and butadiene) are presented. In detail FTIR spectra, XPS surveys, XPS valence bands and core level signals including shake-up features as well as carbon K-edge absorption spectra are qualitatively and, in some cases, semi-quantitatively considered. Information on the film formation, the chemistry of the films and the film stability against air exposure are derived from spectroscopic features. With styrene chemically rather well defined plasma polymer layers can be formed with rather high deposition rates applying a pulse plasma process. Using ethylene, acetylene or butadiene as a monomer in the plasma deposition process the deposition rates are smaller. Using these monomers plasma polymer films can be obtained with a primary chemical structure which is similar to each other but more or less different from those of the respective conventional polymers. The main difference between these samples is their individual concentration of unsaturated carbon species. Finally, a technologically relevant example, i.e. a plasma deposited polymer barrier layer deposited on the inner wall of a poly(ethylene) vessel is briefly considered.