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CF4 plasma treatment of a Teflon-like (1,1,1,2 tetrafluoroethane, TFE) chemical spray deposited on paper resulted in an increased level of elemental fluorine on the paper surface. However, TFE molecules undergo bond cleavage and ionization in the presence of the RF-CF4 plasma environment. The abundant fluorine radicals grafted onto the paper surface, via the substitution and opening of the bonds in the cellulose polymers, yielded CFx (x: 1–3) functionalities, as observed by XPS and ATR-FTIR analyses. Lower power (100 W) and treatment times (0.5 min) were sufficient to obtain very highly fluorinated surfaces. The change in the morphology of the surface by the exposure to plasma was complicated because the localized deposition and re-deposition of the plasma-generated molecules on the paper were superimposed on the surface reactions and degradation (etching) at the paper surface. [ABSTRACT FROM AUTHOR]

Near-ambient pressure x-ray photoelectron spectroscopy (NAP-XPS) is a less-traditional form of XPS that allows samples to be analyzed at relatively high pressures, i.e., at ca. 2500 Pa, or even higher in some cases. With NAP-XPS, XPS can probe moderately volatile liquids, biological samples, porous materials, and/or polymeric materials that outgas significantly. In this submission, the authors show NAP-XPS survey spectra, and C 1s and O 1s narrow scans of two samples of paper (a white office paper and the nonsticky side of a yellow post-it note). The white office paper was analyzed at three specific positions: an unprinted portion, a light blue letter, and a dark blue letter in the "SPECS" logo. Survey spectra show the presence of carbon, oxygen, nitrogen, and calcium in all the samples. The yellow paper shows a small amount of silicon. Fits to the C 1s and O 1s regions are shown. The O 1s narrow scans are fit with four peaks using a literature approach previously employed for paper and with three peaks in a more ad hoc fashion. The latter approach yields better fits. [ABSTRACT FROM AUTHOR]

The plasma duty cycle, in addition to power and exposure time, affects the surface atomic composition of thiophene plasma-treated paper. The elemental carbon and sulfur concentration increased from 56.7% to 78.6% and 0% to 13.4%, respectively, while oxygen decreased from 43.3% to 8.0% with the plasma treatment. Relatively large variations in the deposited film-like layer composition could be realized by changing plasma external parameters. The high-resolution (HR) C1s spectra of the thiophene plasma-treated paper clearly exhibit plasma-induced rearrangements and new sulfur functionalities on the paper surface. After a five-hourex situdoping of thiophene plasma-treated papers with iodine, conductivity ranging from δ = 4.2E-2 to 4.1 S/cm was obtained. The low relative F/C atomic ratio after TFAA derivatization indicates that no hydroxyl groups were present on the paper surface after the thiophene plasma treatment. [ABSTRACT FROM PUBLISHER]

Abstract: Survey and high-resolution (HR) XPS studies indicate that OMCTSO plasma treatment created a new silicon containing functional groups and changed the hydroxyl content on the surface of paper. Four intense survey XPS spectrum peaks were observed for the OMCTSO plasma treated paper. They were the Si2p at 100eV, Si2s at 160eV, C1s at 285eV, and O1s at 525eV for the plasma modified surface. It was realized that the macromolecular chain-breaking mechanisms and plasma-induced etching processes control the number and the availability of OH-functionalities during OMCTSO plasma exposure on paper. The reaction, initiated by these species, depends mainly on the nature of chemicals in the plasma as well as on the energy level of the plasma and the nature of the surface effects in the modification of the paper. The ATR-FTIR spectrum of paper treated with OMCTSO plasma has characteristic absorption bands attributed to the Sice:glyph name="sbnd" />Oions on the surface. [Copyright &y& Elsevier]

Abstract: The surface chemical and physical character of offset paper was studied before and after application of model fountain solutions based on isopropyl alcohol and an alcohol-free surfactant solution. The paper surface features were characterised with atomic force microscopy and the surface energies were determined by contact angle measurements. Changes in the surface chemical properties induced by the fountain solutions were investigated with X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectroscopy. Coated papers wetted with the surfactant solution revealed a slight increase in the root mean square roughness, but the isopropyl alcohol solution led to no observable changes. The change in sub-micro roughness is ascribed not only to substrate swelling or migration of coating constituents but also to the presence of surfactant on the surface. A change in the surface energy and particularly the polar contribution was observed after application of the surfactant solution. The X-ray photoelectron spectroscopy showed an increase in the oxygen-to-carbon ratio, which confirms the presence of surfactant on the surface. Time-of-flight secondary ion mass spectroscopy showed that the isopropyl alcohol solution did not change the elemental composition of the surface whereas the surfactant solution clearly did so. The distribution of surfactant on the surface was confirmed by mapping the characteristic fragments of the molecule. [Copyright &y& Elsevier]

Abstract: The treatment of additive-free hand sheet paper samples with cold plasma was carried out and showed that cellulose can be chemically linked with reactive natural products, namely myrcene (My) and limonene (LM). Contact-angle measurement and X-ray photoelectron spectroscopy (XPS) were used to ascertain the occurrence of the grafting. Indeed, the contact-angle value of a drop of water deposited at the surface of paper increased from 30° for unmodified substrate to about 105 and 107°, for LM- and My-treated samples, respectively. In fact, LM- and My-treated surfaces were rendered totally apolar. Indeed, the polar contribution to the surface energy decreased from about 23 mJ/m2 for pristine samples to practically zero for treated ones. The treated surfaces displayed water-barrier properties; the penetration of the liquid was reduced significantly after LM and My treatments. The XPS spectra showed that the modification with LM and My gave rise to very significant change in the O/C ratio, as well as in the intensity of the C1 peak assigned to aliphatic carbon sequences. [Copyright &y& Elsevier]

Abstract: This work concerns the ageing effect of the atmospheric plasma and corona treatments when used to treat paper substrates. Pigment coated and surface sized papers were modified using two types of atmospheric plasma equipment; one at the pilot scale and one at the laboratory scale. In addition, the plasma treatments were compared to conventional corona treatment. Surface energy was estimated by contact angle measurements and surface chemistry by X-ray photoelectron spectroscopy (XPS) as a function of the time during three months. The treatments increased surface energy and oxidation level of surface for both papers. The ageing effect could be detected only in the surface energy, whereas the oxidation level remained stable during the twelve weeks. The decay in surface energy was faster during the first weeks of storage and subsequently leveled off leading to a permanent change. The permanent change was explained as a contribution of oxygen containing polar molecular groups, which were detected by XPS. The ageing effect was suggested to originate from already existing polar molecular groups, which have rotated on the surface by plasma-related process and then rotate back into the material in time. A part of the decay was also explained by the plasma cleaning model, in which the ageing effect occurred through re-contamination. Paper is a multicomponent system, where the constituents that have the lowest surface energy were suggested to migrate to paper surfaces. [Copyright &y& Elsevier]

Abstract: X-ray photoelectron spectroscopy (XPS) has been applied to pulp and paper research for decades. However, there has been no attempt to standardise or even systematically compare experimental and analysis procedures, even though it is known that fibrous, nature-derived and insulating fibre materials pose remarkable challenges to reliable surface analysis. The experimental problems are mainly linked with neutralisation, energy resolution, contamination and X-ray induced degradation. We have tested applicability, reliability and reproducibility of XPS analysis on real pulp samples with varying lignin and extractives contents in a small round robin investigation. We also tested the instrumental set-ups with an acetone-extracted filter paper, used as a reference sample. The data, collected at four different laboratories with state-of-the-art instruments indicate that reproducible results can be obtained, despite minor differences in experimental and analysis procedures. However, we found that a specified sample handling procedure and limited X-ray exposure are crucial for reproducible, reliable data. Based on the round robin data we recommend dose restricted monochromatic measurements, a cellulosic in situ reference and a consistent sample handling procedure. The data confirms that a paper-based reference material and the correlation of high-resolution C 1s data with O/C atomic ratios can be used in testing instruments and experimental set-ups for pulp and paper materials. [Copyright &y& Elsevier]

Recent instrumental advances have vastly improved the analysis power of X-ray photoelectron spectroscopy (XPS), which has been widely used in applied surface research for decades. In this presentation a set of XPS analysis methods well suited for problems and analytical needs encountered in papermaking technology is presented. The emphasis will be on analysis of pulps and non-coated papers. Examples given describe the use of XPS in quantification of surface lignin and extractives; an alternative approach for evaluating elemental surface distributions via the Tougaard background analysis is also presented. The experimental work and interpretations presented are based on more than two thousand XPS analyses performed at Helsinki University of Technology during 1996–2000. With strictly standardised experimental setup, state-of-the-art instrumentation and a proper combination of analysis methods XPS can yield valuable and consistent information on surface properties of natural fibers. [ABSTRACT FROM AUTHOR]