Search

The jet of reactive effluents produced by surface dielectric barrier discharge was used to deposit PEO-like plasma polymers from di(ethylene) glycol vinyl ether. The jet was confined within the hollow space of either circular cross-section with substrate placed perpendicular to the jet, or rectangular cross-section with the walls used as substrates. The best 67% retention of the ethers was obtained for the circular channel, whereas it was only 50% for the rectangular channel. In the latter case, deposition at longer distances was possible. In both cases, the deposition started with the formation of islands that grew, coalesced and eventually built up a continuous coating.

In the present study is shown a novel vacuum-based technique that enables production of hard polymeric nanocomposite coatings with metal (Cu) nanoparticles. This method is based on the use of gas aggregation source (GAS) of Cu nanoparticles and plasma-enhanced chemical vapour deposition of a-C:H matrix that was deposited in a mixture of Ar and n-hexane on the substrates placed on the powered RF electrode. This approach makes it possible to control independently both the properties of the matrix by variation of the applied RF power and the amount of incorporated Cu nanoparticles that may be adjusted by operational parameters of the GAS. Characterisation of the films in terms of their chemical composition, morphology, optical and mechanical properties is described here alongside with description of Cu nanoparticles production using GAS with variable aggregation length.

Surfaces whose properties change gradually along the sample length, so-called gradient surfaces, are highly interesting for fundamental studies focused on the interaction between biomolecules or cells and surfaces. In this study, we investigate simple, vacuum-based strategy for fabrication of surfaces with gradient nanoroughness and wettability. This approach is based on the application of gas aggregation source of nanoparticles combined with the magnetron sputtering of poly(tetrafluoroethylene). It is shown that this technique makes it possible to produce coatings with invariant surface chemistry, but with gradient roughness in the range 0.5–20 nm and wettability gradient that ranges from 100° up to 150°, i.e., coatings with hydrophobic to superhydrophobic character.

Plasma polymerised PEO-like films were deposited from tetraethylene glycol dimethyl ether (TEGDME) and diethylene glycol vinyl ether (DEGVE) using an atmospheric plasma jet. Films formed from TEGDME with COC retention >50% showed anti-fouling properties, while DEGVE films with COC >60% did not. TEGDME films deposited at higher monomer flow rates had a lower density and more amorphous phases in the polymer network. Consequently, these films more readily facilitate penetration and binding of water to their surface in comparison to the denser DEGVE films. The difference in fouling properties identified through this comparative study has shown that % COC retention may not alone be an indication of non-fouling behaviour. Other factors such as polymer network structure may also play a crucial role in the prevention of surface fouling.

Glancing angle deposition (GLAD) on a smooth substrate has certain limitations, which may be overcome if nanoparticles are deposited first. This study compares the growth of silver columns on a smooth substrate and over pre-deposited small copper (O16 nm) and big C:H plasma polymer nanoparticles (O110 nm). Cu nanoparticles help to the growth of the columns but their surface density does not play a major role. C:H nanoparticles ensure the growth of the column from each particle and therefore increased surface density of C:H nanoparticles results in an increased number of columns. In addition, the columns grow even at very small angles of incidence (40°). At high angles of incidence secondary columns start to grow on primary columns and also on the smooth substrate surface in between them.

Nanocrystalline diamond (NCD) films may be used in biosensing after modification of their surfaces with active functional groups. Here, surface functionalization of O- and H-NCD films with amine groups was made by 2 plasma-based processes: a) RF plasma treatment in ammonia, b) the deposition of thin amine-containing plasma polymer via RF magnetron sputtering of nylon target in Ar/N2 mixture. Amination of the NCD films by plasma treatment in NH3 caused an attachment of 1% of primary amines but destroyed the surface conductivity of H-NCD films. The 5% concentration of NH2 was detected on the NCD covered with the plasma polymer. Moreover, the surface conductivity of H-NCD films reached 10−7 S.

TiO2 nanoparticles and nitrogen-doped TiO2−xNx nanoparticles dispersed in plasma polymer phase are produced by atmospheric pressure DBD in titanium tetraisopropoxide with dry air, mixture of N2 and O2, and 100% N2 used as carrier gases. Energy supply per monomer molecule (the Yasuda parameter) is found to be an important parameter describing the deposition process in N2. In the monomer deficient regime, spherical TiO2 particles are produced with an average size varying from 30 to 80 nm. In the power deficient regime, composite films are deposited consisting of TiO2−xNx nanoparticles embedded in nitrogen-rich plasma polymer matrix, particulates being larger than 100 nm.

The deposition process of C:H:O plasma polymer films was studied at different experimental conditions such as RF power input and acetone/CO2 gas ratio. Aging of the C:H:O films was studied after their storage both in ambient air and in distilled water at different time scales in order to test their stability. Permanent hydrophilic plasma polymers are obtained showing only minor changes during aging that are mainly connected to oxidation and water (water vapor) adsorption (hydration). The amounts of trapped radicals and oxygen atoms in the films, especially the oxygen bonded in ester groups (OCROR), are of the highest importance in aging. It was found out that the most stable C:H:O plasma polymer films are those for which the elemental ratio O/C is lower than 0.2. These films contain less than 10% of ester groups. With a stable water contact angle of around 55° the C:H:O plasma polymer films appear to be suitable for applications in aqueous environments such as, e.g., in the biomedical field.

Particle characterization 36, 1900436 - (2019). doi:10.1002/ppsc.201900436, Kinetic aspects of the synthesis of Ag nanoparticles (NPs) by magnetron sputtering are studied by in situ and time-resolved small angle X-ray scat-tering (SAXS). Part of the NPs are found to become confined within a capture zone at 1–10 mm from the surface of the target and circumscribed by the plasma ring. Three regimes of the NP growth are identified: 1) early growth at which the average NP diameter rapidly increases to 90 nm; 2) cycling instabilities at which the SAXS signal periodically fluctuates either due to expelling of large NPs from the capture zone or due to the axial rotation of the NP cloud; and 3) steady-state synthesis at which stable synthesis of the NPs is achieved. The NP confinement within the capture zone is driven by the balance of forces, the electrostatic force being dominant. On reaching the critical size, large NPs acquire an excessive charge and become expelled from the capture zone via the electrostatic interactions. As a result, signifi-cant NP deposits are formed on the inner walls of the aggregation chamber as well as in the central area of the target, Published by Verl. Chemie, Weinheim

This multi-centre investigation explores the variability that results from using the power/flow rate ratio (W/F) to describe plasma treatment and plasma polymerization processes. Results from fourteen reactors of different design and spread across ten laboratories, showed that the chemistry of the treated and deposited polymer/plasma polymer films is highly variable between reactor systems, and that there was no clear pattern linking these variations to other properties of the reactor systems (e.g. pressure, volume, electrode configuration). Although W/FM provides a useful rule-of-thumb for process optimization within a single system, it does not provide sufficient information to enable the same plasma polymer to be produced on a different system.

Cell behavior depends strongly on the physical and chemical properties of the material surface, for example, its chemistry and topography. The authors have therefore assessed the influence of materials of different chemical composition (i.e., glass substrates with and without TiO(2) films in anatase form) and different surface roughness (R(a) = 0, 40, 100, or 170 nm) on the adhesion, proliferation, and osteogenic differentiation of human osteoblast-like MG63 cells. On day 1 after seeding, the largest cell spreading area was found on flat TiO(2) films (R(a) = 0 nm). On TiO(2) films with R(a) = 170 nm, the cell spreading area was larger and the number of initially adhering cells was higher than the values on the corresponding uncoated glass. On day 3 after seeding, the cell number was higher on the TiO(2) films (R(a) = 0 and 40 nm) than on the corresponding glass substrates and the standard polystyrene dishes. On day 7, all TiO(2) films contained higher cell numbers than the corresponding glass substrates, and the cells on the TiO(2) films with R(a) = 40 and 100 nm also contained a higher concentration of β-actin. These results indicate that TiO(2) coating had a positive influence on the adhesion and subsequent proliferation of MG63 cells. In addition, on all investigated materials, the cell population density achieved on day 7 decreased with increasing surface roughness. The concentration of osteocalcin, measured per mg of protein, was significantly lower in the cells on rougher TiO(2) films (R(a) = 100 and 170 nm) than in the cells on the polystyrene dishes. Thus, it can be concluded that the adhesion, growth, and phenotypic maturation of MG63 cells were controlled by the interplay between the material chemistry and surface topography, and were usually better on smoother and TiO(2)-coated surfaces than on rougher and uncoated glass substrates.

This work investigates the possibility to prepare PEO-like plasma polymers by using an AC surface dielectric barrier discharge in argon with admixtures of di(ethylene glycol) monovinyl ether vapors at atmospheric pressure. The surface discharge was driven in an amplitudemodulated regime with a driving AC frequency of 5 kHz with a variable discharge duty cycle of 0.2–0.8. Deposition of plasma polymers was tested for variable argon flow rate of 0.5–2 slm and for various distances between the discharge electrode surface and deposition substrates. The measurements of electro-optical discharge characteristics and infrared analysis of deposited films were performed to fix suitable deposition conditions. Best retention of PEO-like character was obtained for the following conditions: the distance between substrates and discharge surface of 3 mm, argon flow rate of 1 slm, excitation AC high voltage of 2.2 kV (peak-to-peak) and discharge duty cycle of 0.4.

studied the effect ofpressure of argon as working gas at a constant distance of5cm between PTFE target and a substrate. It was shownthat both the chemistry, and the roughness of the surfacechanged with the Ar pressure during sputtering. Theauthorsconsideredthesurfaceroughnesstobeimportantfor the targeted super-hydrophobic effect. However, theroughness did not increase gradually with the pressure,but increased by a sudden jump for the highest pressure70Pa used. This result was interpreted as indicatingthat the plasma polymer clusters (nano and microparticles)formedintheplasmavolumewereburiedinto the plasma polymer film growing on the substrate.This happened under particular deposition conditions(flow of argon, RF power, target-substrate distance) atAr pressure of about 70Pa and higher. Based onscanningelectron microscopy (SEM) micrographs, this seemed toconfirmthehypothesisthatfluorocarbonplasmapolymerparticlesoriginatingintheplasmavolume(dustyplasma)were eventually embedded into the film growing onthe substrate.On the other hand, several research groups claimed thatclusters (actually PTFE crystals) grown from CF

Polyethylene oxide (PEO)-like films were prepared by rf magnetron sputtering of PEO and by thermal evaporation of PEO with and without activation by argon plasma. Rf magnetron sputtering under low power (

Planar RF magnetron was used for sputtering of nylon in Ar, N2 and their mixtures. The discharge plasma was monitored by mass spectrometry and optical emission spectroscopy. By means of these two diagnostic methods various carbon-containing species were detected and their densities were found to increase with increasing portion of N2 in the discharge mixture. Moreover, it has been demonstrated that such species govern the deposition rate as well as chemical composition of the deposits determined both in situ and ex situ by FT-IR spectroscopy and XPS.

Thermal decomposition (“evaporation”) of polyethylene (PE) was performed with or without an activation of volatile fragments in an rf glow discharge. Study of the deposition process via quadrupole mass spectrometry showed the presence of hydrocarbon fragments up to 100 amu. Properties of the resulting films were investigated by means of FTIR, XPS, and NMR spectroscopy. These analyses showed that the activation of polymeric fragments in plasma enhances cross-linking and the films become hydrocarbon plasma polymers. However, these plasma polymers resemble much more the original PE. In addition, NMR technique enabled to assess the ratio of crystalline and amorphous phases in the films.

Nanocomposite Ti/hydrocarbon plasma polymer (Ti/ppCH) films were deposited by DC magnetron sputtering of titanium target in n-hexane, argon, or a mixture of these two gases. The resultant films were heterogeneous, with inorganic regions of nanometer scale distributed within a plasma polymer matrix. The titanium content was controlled by adjusting the argon/n-hexane ratio in the working gas. In the pure n-hexane atmosphere, the Ti concentration was found to be below 1 at %, whereas in pure argon it reached 20 at %, as measured by Rutherford backscattering spectroscopy and elastic recoil detection analysis (RBS/ERDA). A high level of titanium oxidation is detected with TiO(2), substoichiometric titania, and titanium carbide, composing an inorganic phase of the composite films. In addition, high hydrogen content is detected in films rich with titanium. Ti-deficient and Ti-rich films proved equally good substrates for adhesion and growth of cultured human osteoblast-like MG 63 cells. In these cells, the population densities on days 1, 3, and 7 after seeding, spreading area on day 1, formation of talin-containing focal adhesion plaques as well as concentrations of talin and osteocalcin (per mg of protein) were comparable to the values obtained in cells on the reference cell culture materials, represented by microscopic glass coverslips or a polystyrene dish. An interesting finding was made when the Ti/ppCH films were seeded with calf pulmonary artery endothelial cells of the line CPAE. The cell population densities, the spreading area and also the concentration of von Willebrand factor, a marker of endothelial cell maturation, were significantly higher on Ti-rich than on Ti-deficient films. On Ti-rich films, these parameters were also higher or similar in comparison with the reference cell culture materials. Thus, both types of films could be used for coating bone implants, of which the Ti-rich film remains effective in enhancing the endothelialization of blood contacting artificial materials.

The application of FT-IR vibration spectroscopy to the analysis of various interaction events that occur at the interface between a silver surface (including nanoparticles) and the surrounding environment is discussed. In particular, the adsorption of hydrocarbons, CO, and CO 2 on silver as well as an oxidation behavior and related phenomena are reviewed. A concise discussion of FT-IR investigations of nanocomposite Ag/plasma polymer films is given in conclusion.

A plasma polymer coating from a hexane/argon mixture is deposited on PE. Protein attachment is investigated after incubation in a HRP-containing buffer solution. Covalent bonding of the attached HRP is demonstrated by means of ATR FT-IR, which shows that the protein peaks persist after washing in heated SDS solution. An enzyme activity assay demonstrates high levels of bioactivity of the attached protein over several days after washing. The retention of the protein's bioactivity depends on the coating's structure, which in turn depends on the potential between the plasma and the surface during deposition. Covalent coupling is less sensitive to polymerization parameters and occurred on polymer layers deposited both on grounded and negatively self-biased electrodes.

The influence of direct current (DC) discharges in oxygen and water vapor and in a flowing afterglow of water vapor discharge onto the surface of poly(propylene) (PP) films was studied. The surface properties of PP were characterized by Fourier transform infrared by attenuated total reflectance (FTIR/ATR), X-ray photoelectron spectroscopy (XPS), Atomic force microscopy (AFM), and contact angle measurement. The action of oxygen and water vapor plasma was found to be similar in terms of the composition of functional groups formed. Unlike plasma action, the PP surface treatment in water vapor discharge afterglow provided a more uniform composition of oxygen-containing groups and greater depth of the modified layer. The formation of alcohol, carbonyl, and carboxyl groups has been observed. The treatment of PP films led to the increase in surface-free energy, the polymer surface becoming more smooth and homogeneous.

Titanyl phthalocyanine (TiOPc) thin films were prepared using evaporation and surface polymerization by ion-assisted deposition (SPIAD) in a vacuum deposition system. These films were characterized by means of ultraviolet and X-ray photoelectron spectroscopy as well as UV/Vis absorption spectroscopy. Valence band and elemental content indicated that phthalocyanine electronic and chemical structures were largely preserved during SPIAD. Further, bilayer thin films of titania (TiO 2 ) and SPIAD TiOPc were prepared. TiO 2 film was deposited by reactive magnetron sputtering of TiO 2 target. Study of the structured samples was focused on the optical and electrical properties of the composite films. The films were characterized by noncontact photovoltage measurements and UV-Vis spectroscopy. These results suggest there is a possibility to use these bilayer thin films in photovoltaic solar cells, however further experiments to improve conductivity of the films will be required.

This study describes the preparation and the properties of TiO x /hydrocarbon plasma polymer composite films. Films are prepared by simultaneous sputtering in argon from two balanced magnetrons equipped with TiO 2 and PP targets. The resulting films exhibit a wide range of properties in dependence on the preparation conditions - primarily on the ratio of the deposition rates r(TiO x )/r(PP) and thus the power delivered to the magnetrons. The deposition process is monitored by optical emission spectroscopy. The composition and morphology of the composite films have been analyzed by means of RBS/ERDA, FTIR, AFM, and TEM. Optical properties of the films are studied in the UV and visible range of the spectrum. Finally, an attempt has been made to express the amount of inorganic phase present in the organic matrix in terms of a filling factor.

Poly(propylene) was RF sputtered in a working gas mixture of argon and nitrogen using planar magnetron. With nitrogen content in the mixture increasing from 0 to 100%, the deposition rate of plasma polymer films increased from 3 to 12 nm · min−1, the contact angle of water on sputtered plasma polymer films decreased from 62 to 37° and, according to FTIR measurements, the presence of NH and CN groups in these films increased. According to XPS, at 0% nitrogen in the working gas mixture the films contained more than 10 at.-% of oxygen; with increasing content of nitrogen in the gas mixture this proportion steadily decreased whereas the nitrogen content in the film increased. When RF power was increased, the deposition rate and contact angle increased. Qualitative explanation of the deposition process is proposed.

Core@shell Cu/hydrocarbon plasma polymer nanoparticles (NPs) have been prepared using a gas aggregation cluster source followed by in-flight plasma polymer coating of produced Cu NPs. Conventional plasma polymerization of vapors of n-Hexane or acetone has been applied. It is shown that this strategy for core@shell NPs production enables to achieve homogeneous shells with thickness in nanometer scale without impact on the properties of metallic cores (crystallinity, optical properties). In addition, it has been proved that the chemical properties of shells may be controlled by use of different organic precursors that enables production of NPs with different wettabilities.

The nanocomposite films Ag/a-C:H were prepared by vacuum-based method which combines deposition of Ag nanoparticles by means of gas aggregation source (GAS) and PECVD deposition of a-C:H matrix. The matrix was deposited in a mixture of Ar and n-hexane on the substrates placed on the powered RF electrode facing the beam of Ag NPs from the GAS. Anisotropic plasma etching was used to increase Ag concentration on the surface of the coating. The influence of three types of plasma on the chemical composition of the coatings and on the size of Ag nanoparticles is described. It is shown that the best etching selectivity and thus the highest Ag surface concentration was reached in case of etching of grounded samples in low pressure oxygen plasma. This treatment enhances the short term antibacterial efficiency of produced coatings.

Cellulose acetate membranes (CA) were modified by means of plasma polymerization of ethylene diamine (EDA) and n-butylamine (n-BA). The motivation for this work was the application of a modified membrane for the single-layer enzyme electrode. A tubular reactor with the external radiofrequency (13.56 MHz) excitation was used. Surface modification was performed at 5, 10, and 15 W power (at 27 Pa working pressure) for 5, 10, 15 min. Modified surfaces were characterized in detail by FTIR–ATR, XPS (ESCA), contact angle, and enzyme immobilization activity. The best treatment results were obtained for EDA with 5 W and 30 min and 15 W and 10 min. These results are discussed using surface analysis data. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1341–1352, 2001