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One of the leading causes of failure for any bone implant is implant-associated infections. The implant-bone interface is in fact the crucial site of infection where both the microorganisms and cells compete to populate the newly introduced implant surface. Most of the work dealing with this issue has focused on the design of implant coatings capable of preventing infection while ignoring cell proliferation or vice versa. The present study is therefore focused on investigating the antibacterial and biological properties of nanocomposite coatings based on an amorphous hydrocarbon (a-C:H) matrix containing silver nanoparticles (AgNPs). a-C:H coatings with varying silver concentrations were generated directly on medical grade titanium substrates using a combination of a gas aggregation source (GAS) and a plasma-enhanced chemical vapor deposition (PE-CVD) process. The obtained results revealed that the surface silver content increased from 1.3 at % to 5.3 at % by increasing the used DC magnetron current in the GAS from 200 to 500 mA. The in vitro antibacterial assays revealed that the nanocomposites with the highest number of silver content exhibited excellent antibacterial activities resulting in a 6-log reduction of Escherichia coli and a 4-log reduction of Staphylococcus aureus after 24 h of incubation. An MTT assay, fluorescence live/dead staining, and SEM microscopy observations of MC3T3 cells seeded on the uncoated and coated Ti substrates also showed that increasing the amount of AgNPs in the nanocomposites had no notable impact on their cytocompatibility, while improved cell proliferation was especially observed for the nanocomposites possessing a low amount of AgNPs. These controllable Ag/a-C:H nanocomposites on Ti substrates, which simultaneously provide an excellent antibacterial performance and good biocompatibility, could thus have promising applications in orthopedics and other biomedical implants.

The study focuses on the synthesis of two-component heterogeneous nanoparticles with plasma polymer core decorated with silver. It is shown that such strawberry-like particles may be easily produced by the strategy that involves the in-flight deposition of silver onto plasma polymer particles produced by gas aggregation source.

The impact of surface roughness on wettability and droplet drying dynamics was investigated on coatings with a spatially homogeneous chemical composition, but with a gradient in their roughness. Such coatings were prepared by a simple vacuum-based technique that utilizes a combination of a gas aggregation source of Ag nanoparticles and the radio-frequency magnetron sputtering of hydrophobic polytetrafluoroethylene. It was demonstrated that the roughness influenced not only the static water contact angle that monotonously increases with increasing roughness, but also had a strong impact on the water contact hysteresis, as well as on the dynamics of droplet drying.

A novel technique that enables the production of a-C:H coatings decorated either by sub-micron concave or convex structures is presented. The technique is based on several steps that involve i) pre-seeding of substrates with C:H sub-micron particles produced by a gas aggregation cluster source, ii) overcoating of the C:H particles by thin a-C:H coatings produced by plasma enhanced chemical vapor deposition and iii) optional ultrasonic lift-off of the C:H particles. The main focus is set on the characterization of the morphology of the resultant structures as well as on the comparison of their wettability. It is shown that the properties of the structured a-C:H coatings may be precisely controlled by the number of the C:H particles. Different dynamic wetting of convex and concave structures is reported, although static wettability is the same. For concave wells (maximum depth 90 nm) the dynamics of water droplet drying is similar to the one observed on smooth a-C:H films and is characterized by three well-distinguishable phases – the constant contact radius phase, the constant contact angle phase and the mixed phase – independently of the number of wells. By contrast, the increasing number of convex bumps (300 nm in height) gradually impedes the movement of a triple line which progressively suppresses the constant contact angle phase. Subsequently, the differences in the droplet drying have a strong impact on the bovine serum albumin patterns formed after the complete evaporation of droplets. Spatially irregular protein pattern is observed on smooth and well-decorated concave a-C:H coatings while a well-defined “coffee-ring” structure is formed on the a-C:H coatings decorated with convex structures.

In a typical sputter-based gas aggregation cluster source (GAS), nanoparticles (NPs) are created from supersaturated vapours of the target material. The NPs then escape from the source with the expanding gas through an exit orifice. The carrier gas flow profile is one of the most critical parameters, which strongly affects the NP losses on the walls and determines the efficiency of the NP transport to the substrate. In this work, computational fluid dynamics (CFD) simulations are performed to understand the flow of the carrier gas inside the aggregation chamber. We focus on the impact of the inlet and outlet geometry on the carrier gas flow and, therefore, on the NP transportation. Two types of GAS with either a conventional planar magnetron or a cylindrical magnetron are considered. In the planar configuration, the working gas inlet is from behind the magnetron, and the gas flows around the target towards the orifice along the system axis, which may cause some vertices. The situation is even more critical for the cylindrical magnetron, where the gas inlet position and geometry have a drastic influence on the gas flow. Brownian diffusion is found to prevail for NPs smaller than 5 nm, regardless of the gas flow. This leads to their losses on the walls. Larger NPs experience a stronger drag force from the carrier gas flow, which should exceed 10 m s−1 to prevent loss of NPs on the walls and keep NP transport efficient. Therefore, the CFD simulations help to visualise the motion of the NPs and optimise the geometry of the GAS for future applications.

In this paper, the frictional behavior of a neutral hydrogel, polyvinyl alcohol (PVA), on smooth solid substrates with various levels of hydrophobicity have been investigated in water using a strain-controlled parallel-plate rheometer. For the sliding velocity dependence of friction, we detected a distinct friction transition on hydrophobic substrates that are strongly adhesive to the gel, while no clear transition was observed on hydrophilic substrates that are weakly adhesive to the gel. Even on the most hydrophobic substrate, the maximum frictional stress is approximately 1/10–1/5 of the gel’s elastic modulus under a large normal strain of 26%. Furthermore, the frictional stress on hydrophobic substrates in the high velocity region, larger than the transition, is much lower than that on hydrophilic ones. We attempted to explain these phenomena with the help of two models: a molecular model based on the thermal fluctuations occurring during adsorption–desorption of polymers and a continuum mechanics model based on elastic dewetting and forced wetting.

Infection associated with titanium based implants remains the most serious problem in implant surgery hence it is important to find optimal strategies to prevent infections. In the present study, we investigated the surface properties, antibacterial activity and biocompatibility of nanocomposite coatings based on an amorphous hydrocarbon (a-C:H) film containing copper nanoparticles (CuNPs) deposited on Ti discs via a gas aggregation cluster source. Three different Cu/a-C:H coatings with approximately the same amount of embedded CuNPs with and without barrier a-C:H layer were fabricated. The obtained results revealed that different structures of the produced coatings have significantly different release rates of Cu ions from the coatings into the aqueous media. This subsequently influences the antibacterial efficiency and osteoblast cell viability of the treated coatings. Coatings with the highest number of CuNPs resulted in excellent antibacterial activity exhibiting approximately 4 log reduction of E.coli and S.aureus after 24 h incubation. The cytotoxicity study revealed that after 7 day cell seeding, even the coating with the highest Cu at.% (4 at.%) showed a cell viability of 90%. Consequently, the coating, formed with a properly tailored number of CuNPs and a-C:H barrier thickness offer a strong antibacterial effect without any harm to osteoblast cells.

Vacuum-based strategy for production of super-hydrophilic nanostructured SiOx coatings on conventional polymers was developed. This method is based on pre-seeding of polymers with Ag nanoparticles fabricated by means of gas aggregation source of nanoparticles prior to the SiOx deposition. It is shown that at a sufficiently large amount of Ag nanoparticles the produced coatings exhibited nanotexture that possessed temporally stable super-hydrophilic character with water contact angles lower than 10° for a period of 2 years.

C:H:O plasma polymer films (PPFs) were deposited by means of plasma-enhanced chemical vapour deposition using the non-toxic, biodegradable organic compound dimethyl carbonate (DMC) at various plasma powers and pressures in order to control the degradation properties related to the carbonate ester group. Coating properties using pure DMC monomer vapours were compared to co-polymerized films from gaseous mixtures of DMC with either ethylene (C2H4) or carbon dioxide (CO2) affecting deposition rate and chemical composition. C:H:O film properties were found to depend primarily on the amount of oxygen in the plasma. To investigate the PPF stability during aging, changes in the composition and properties were studied during their storage both in air and in distilled water over extended periods up to 5 months. It was shown that aging of the films is mostly due to oxidation of the plasma polymer matrix yielding slow degradation and decomposition. The aging processes and their rate are dependent on the intrinsic amount of oxygen in the as-prepared C:H:O films which in turn depends on the experimental conditions and the working gas mixture. Adjustable film properties were mainly attained using a pure DMC plasma considering both gas phase and surface processes. It is thus possible to prepare C:H:O PPFs with controllable degradability both in air and in water.

Wettability and water droplet drying dynamics on poly(ether-ether-ketone) (PEEK) foils treated by atmospheric pressure air dielectric barrier discharge (DBD) has been investigated. It has been found that plasma treatment causes significant increase of PEEK wettability that is predominantly connected with alterations of its chemical composition (oxidation) induced by DBD plasma. The hydrophilization of PEEK surface was not temporally stable and substantial increase of water contact angle up to 67° was observed with increasing storage time, which is consistent with loosening of polar groups as confirmed by means of XPS. Characteristic restoration time of the contact angle was 6.7 days. Furthermore, a large alteration of the dynamics of water droplets drying on PEEK after the plasma treatment was also observed: whereas for untreated PEEK three drying phases were clearly distinguishable, the phase of constant contact angle disappeared in the case of PEEK exposed to the atmospheric pressure air plasma. In spite of substantial decrease of PEEK wettability with storage time the constant angle phase didn't appear within 51 days after the plasma treatment. As a result of this plasma treated and aged PEEK exhibits much higher water contact hysteresis as compared to untreated PEEK. This effect may be explained by the formation of randomly distributed nanostructures on PEEK surface exposed to DBD plasma that increase the spatial heterogeneity of the PEEK surface and enhance droplet pinning during its drying.

Controlled synthesis of core@shell nanoparticles (NPs) for certain applications is a difficult challenge in many nanotechnology projects. In this report, a conventional arrangement composed of a gas aggregation source (GAS) is employed to generate the core NPs, which are subsequently coated by the shell materials in a secondary planar magnetron sputtering. The important difference to the usual system is the application of the two opposing planar magnetrons in a closed field configuration. The prepared core Ag NPs by a GAS are coated/treated by the two magnetrons with Ti targets. Our findings clearly show that the shell thickness can be controlled by tuning the power delivered to the secondary magnetron plasma. Characterizations of the prepared films, by x-ray diffraction technique, disclose multi-crystalline cores covered by amorphous shells. Based on x-ray photoelectron spectroscopy and energy dispersive x-ray spectroscopy measurements, different chemistry on the NPs surfaces and volume of the NPs can be achieved by tuning the operation conditions. Furthermore, the thermal annealing process leads to the growth of the crystallite size which results in emerging some microparticles caused by accelerating Ag surface mobility. The employed technique promises a reliable route to synthesize different heterogeneous NPs with stoichiometry tunable in a wide range for multi-functional devices.

Among strategies of fuel production, photoelectrochemical water splitting for hydrogen generation is garnering significant attention. The challenge for solar energy harvesting is material development with intense photocatalytic activity, efficient free-charge generation, separation, and transport. Tantalum nitride (Ta3N5) and oxynitrides (Ta3NyOx) are recognized as promising candidates for this role. This research suggests a new route to engineer Ta3NyOx nanoparticles (NPs) with structure, crystallinity, chemical, and optoelectronic properties controlled by design. This work employs a single-step plasma-based technique that takes advantage of dc reactive magnetron sputtering of tantalum in Ar/N2 mixtures. The NPs with the chemical composition of Ta3N3.9O0.6 are synthesized; however, they become partially oxidized when exposed to air, providing an inwardly-directed gradient of the nitrogen concentration. The core-region consists of n-type sub-stoichiometric Ta3Ny with a band gap of

This contribution reviews plasma polymer nanoparticles produced by gas aggregation cluster sources either via plasma polymerization of volatile monomers or via radio frequency (RF) magnetron sputtering of conventional polymers. The formation of hydrocarbon, fluorocarbon, silicon- and nitrogen-containing plasma polymer nanoparticles as well as core@shell nanoparticles based on plasma polymers is discussed with a focus on the development of novel nanostructured surfaces.

Plasma polymers are employed in impressive range of applications due to their unique properties. Although films of plasma polymers are traditionally described as smooth and pinhole free, the possibility to produce nanorough and nanostructured plasma polymerized coatings receives increasing attention. In this study, we tested a fully vacuum-based strategy for production of nanostructured plasma polymers. In the first step of this method, the smooth substrate is seeded by plasma polymer nanoparticles produced by means of a gas aggregation source with a semi-hollow magnetron equipped with a Nylon target. In the second step, the nanoparticles are subjected to fluxes of organic fragments produced by magnetron sputtering of Nylon and such depositions are performed at various angles of incidence. As observed, this enables at higher incidence angles to prepare coatings with well-separated individual plasma polymer nanocolumns.

Gradient surfaces, i.e. surfaces whose properties change gradually along the sample length, receive increasing attention as they facilitate optimization of surface properties for particular applications. In this study we present vacuum-based strategy for fabrication of irregular silver nanoparticle arrays with gradient optical properties. This approach is based on the magnetron sputtering of Ag performed at low pressure in argon atmosphere. The gradient character of deposited arrays is achieved by use of a movable mask that is introduced in the vicinity of the substrate. It is shown that this technique enables to tailor the course of the gradient of localized surface plasmon resonance (LPSR) either by the speed of the mask or by additional deposition of silver on the top of surface pre-seeded by the gradient nanoparticle arrays.

We report and compare two vacuum-based strategies to produce Ag/Au materials characterized by double plasmon resonance peaks: magnetron sputtering and method based on the use of gas aggregation sources (GAS) of nanoparticles. It was observed that the double plasmon resonance peaks may be achieved by both of these methods and that the intensities of individual localized surface plasmon resonance peaks may be tuned by deposition conditions. However, in the case of sputter deposition it was necessary to introduce a separation dielectric interlayer in between individual Ag and Au nanoparticle films which was not the case of films prepared by GAS systems. The differences in the optical properties of sputter deposited bimetallic Ag/Au films and coatings consisted of individual Ag and Au nanoparticles produced by GAS is ascribed to the divers mechanisms of nanoparticles formation.

Bio-decontamination of surfaces by means of atmospheric pressure plasma is nowadays extensively studied as it represents promising alternative to commonly used sterilization/decontamination techniques. The non-equilibrium atmospheric pressure plasmas were already reported to be highly effective in removal of a wide range of biological residual from surfaces. Nevertheless the kinetics of removal of biological contamination from surfaces is still not well understood as the majority of performed studies were based on ex-situ evaluation of etching rates, which did not allow investigating details of plasma action on biomolecules. This study therefore presents a real-time, in-situ ellipsometric characterization of removal of bovine serum albumin (BSA) from surfaces by low-temperature atmospheric plasma jet operated in argon. Non-linear and at shorter distances between treated samples and nozzle of the plasma jet also non-monotonic dependence of the removal rate on the treatment duration was observed. According to additional measurements focused on the determination of chemical changes of treated BSA as well as temperature measurements, the observed behavior is most likely connected with two opposing effects: the formation of a thin layer on the top of BSA deposit enriched in inorganic compounds, whose presence causes a gradual decrease of removal efficiency, and slight heating of BSA that facilitates its degradation and volatilization induced by chemically active radicals produced by the plasma.

Atmospheric air plasma treatment of chitosan solutions leads to degradation of chitosan molecules by OH radicals and is accompanied by a predominant cleavage of glycosidic linkages and by a decrease of the molecular weight. The degradation proceeds via first order kinetics with the rate constant of (5.73 ± 0.22) × 10−6 s−1 and the energetic yield of chitosan bond scission of (2.4 ± 0.2) × 10−8 mol/J. Products of degradation together with intact chitosan molecules adsorb and form coatings on polypropylene foils immersed into the solution that is being plasma treated. The plasma treatment results in strong binding of chitosan to polypropylene due to the formation of covalent bonds between the activated polymer surface and chitosan molecules. Plasma-driven crosslinking is responsible for the accumulation of compressive stress which leads to the development of buckling instabilities in the chitosan coatings.

Plasma polymerized poly(ethylene oxide) (pPEO) thin films were deposited by plasma assisted physical vapor deposition (PAPVD) with a constant thickness of 500 nm. The crosslinking density of pPEO films was controlled through the discharge power. Differential scanning calorimetry (DSC) and broadband dielectric spectroscopy (BDS) were applied to analyze the structural peculiarities of these coatings. Both DSC and BDS detected an increase of the crosslink density with power, which correlated with the increasing dynamic glass transition temperature (Tg). It was shown that plasma power changes the structure of plasma polymer, and dielectric spectroscopy may be a suitable technique for structural analysis.

Silver nanoparticle-based antibacterial nanocomposite coatings were fabricated by means of gas aggregation source of Ag nanoparticles and plasma-enhanced chemical vapour deposition of matrix material. Combination of these techniques makes it possible to independently control the amount of Ag nanoparticles in the nanocomposites, as well as properties of matrix material, such as its chemical composition or wettability. This subsequently enables to tune kinetics of silver ion release and hence the antibacterial performance of produced nanocomposites. Based on detail measurements of silver ion release from Ag/plasma polymerized hexamethyldisiloxane and Ag/SiOx nanocomposites, it may be concluded that the release rate is strongly dependent both on matrix material and amount of Ag nanoparticles present in the nanocomposite. These measurements are furthermore accompanied with tests focused on the evaluation of antibacterial potency of produced nanocomposites.

In recent years, highly cross-linked plasma polymers have started to unveil their potential in numerous biomedical applications in thin-film form. However, conventional diagnostic methods often fail due to their diverse molecular dynamics conformations. Here, glassy dynamics and the melting transition of thin PEO-like plasma assisted deposited (ppPEO) films (thickness 100 nm) were in situ studied by a combination of specific heat spectroscopy, utilizing a pJ/K sensitive ac-calorimeter chip, and composition analytical techniques. Different cross-linking densities were obtained by different plasma powers during the deposition of the films. Glassy dynamics were observed for all values of the plasma power. It was found that the glassy dynamics slows down with increasing the plasma power. Moreover, the underlying relaxation time spectra broaden indicating that the molecular motions become more heterogeneous with increasing plasma power. In a second set of the experiment, the melting behavior of the ppPEO films was studied. The melting temperature of ppPEO was found to decrease with increasing plasma power. This was explained by a decrease of the order in the crystals due to formation of chemical defects during the plasma process.

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 this study it is presented fully vacuum-based, substrate independent method for fabrication of fluorine-free superhydrophobic surfaces based on combination of gas aggregation sources of nanoparticles and plasma polymerization. This method involves deposition of films of nanoparticles that are subsequently overcoated by plasma polymerized n-hexane. Two different kinds of nanoparticles that differ significantly in their sizes were used: small Cu nanoparticles (mean diameter 18 nm) and big plasma polymerized C:H nanoparticles (diameter 110 nm). It is demonstrated that superhydrophobic and slippery character may be achieved when surfaces with dual-scale roughness were prepared combining bigger C:H nanoparticles with smaller Cu nanoparticles.

AgCu Janus nanoparticles (NPs) were prepared by coating of Ag NPs in flight. The Ag NPs, produced by a gas aggregation source, were coated with Cu during their flight through a tubular magnetron (TMG). Their structure and chemical composition were studied to establish their dependence on the TMG’s operational parameters. The main focus was the influence of the TMG’s current and magnetic field. It was found that trapping of the NPs occurred at a certain combination of these two parameters. When trapping happened, the size of the NPs and their Cu content increased significantly. We have demonstrated that we can vary the composition of the NP’s produced from pristine Ag from perfect Janus NPs with a Ag/Cu ratio of 50/50, to almost-pure Cu NPs with tiny Ag inclusions.

In certain medical interventions, temporally introduced bone implants are required to exhibit high biocompatibility, yet combined with low osseointegration, to allow for their easy removal afterwards. In this work, Ta2O5 surfaces are developed with good biocompatibility and with the osteoblast adhesion regulated by the nano-topography. The surfaces with convex nano-curvature are produced by applying reactive magnetron sputtering of tantalum over sub-monolayers of hydrocarbon plasma polymer particles. Subsequent ultrasonication leads to the removal of the particles from the coatings and results in the formation of the surfaces with concave nano-curvature. Primary human osteoblasts are found to sustain the viability and the mineralization ability on all kinds of these surfaces; however, Ta2O5 with the concave topography shows restrained adhesion of the cells. The limited cell adhesion is associated with a closed nature of the concave cavities which poses additional potential barriers for protein-mediated cell-surface interactions.

Covalent immobilization of biomolecules to surfaces is desirable in applications in biomedicine and biotechnology, such as biosensors, protein microarrays and implantable biomedical devices. Surface-embedded radicals in polymers, produced by plasma immersion ion implantation, are known to covalently immobilize biomolecules directly from buffer without additional reagents. Here we explore the prospects for creating a surface activated for direct covalent immobilization using a dielectric barrier discharge in air at atmospheric pressure, eliminating the need for vacuum and gas feed systems. We find that a surface activation process at atmospheric pressure in air can activate polytetrafluoroethylene (PTFE) in order to achieve reagent-free covalent immobilization of biomolecules. The presence of surface immobilized protein was verified by X-ray photoelectron spectroscopy (XPS), and its covalent immobilization was demonstrated by resilience to rigorous SDS washing at elevated temperature. Time course immobilization studies show that the covalent coupling capability of the activated surfaces is retained for several days. Proof-of-concept cell assays with immobilized tropoelastin demonstrate the technique’s ability to present functional cell binding molecules for the production of truly bioactive surfaces.

Thin films based on polylactic acid have been prepared using plasma-assisted vacuum thermal deposition under varying RF glow discharge power and characterized in terms of chemical composition and structural homogeneity. As a measure of the degradability of the films their wash-off and hydrolysis behavior were monitored. The properties of the films were found to be tunable to a significant degree by the deposition conditions.

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 treatment of porous materials has huge potential in many applications where chemical modification of interior structure or its loading with polymeric matrices is required. Plasma polymers are often assumed to grow conformally on solid supports; however, their innate roughness may interfere with the surface topography at mesoscale. Here, model mesoporous coatings were prepared by deposition of titanium nanoparticles with the average size of 50 nm onto flat silicon substrates. The nanoparticles were fabricated by magnetron sputtering in the configuration of a gas aggregation source. The porous coatings were subsequently subjected to deposition of soft hydrocarbon plasma polymers from n-hexane. In the early stage of the deposition, negligible increase of thickness is observed as the plasma polymer fills the inner free space of the coatings. The topographical features expand in lateral dimension, but the RMS roughness does not change. In the late growth regime, the inner voids become filled and the pla...

Hydrocarbon polymer films (ppCH) enriched with various concentrations of titanium were deposited on microscopic glass slides by magnetron sputtering from a Ti target. The maximum concentration of Ti (about 20 at.%) was achieved in a pure argon atmosphere. The concentration of Ti decreased rapidly after n-hexane vapors were introduced into the plasma discharge, and reached zero values at n-hexane flow of 0.66 sccm. The decrease in Ti concentration was associated with decreasing oxygen and titanium carbide concentration in the films, decreasing wettability (the water drop contact angle increased from 20° to 91°) and decreasing root-mean-square roughness (from 3.3 nm to 1.0 nm). The human osteoblast-like MG-63 cells cultured on pure ppCH films and on films with 20 at.% of Ti showed relatively high concentrations of ICAM-1, a marker of cell immune activation. Lower concentrations of Ti (mainly 5 at.%) improved cell adhesion and osteogenic differentiation, as revealed by higher concentrations of talin, vinculin and osteocalcin. Higher Ti concentrations (15 at.%) supported cell growth, as indicated by the highest final cell population densities on day 7 after seeding. Thus, enrichment of ppCH films with appropriate concentrations of Ti makes these films more suitable for potential coatings of bone implants.

In this contribution an effect of dielectric barrier discharge (DBD) sustained in air at atmospheric pressure on surface properties of poly(ethylene terephthalate) (PET) foils is studied. It is found that exposure of PET to DBD plasma leads to rapid changes of surface chemical composition, wettability, surface morphology as well as mechanical properties of PET surface. In addition, based on biological tests that were performed using two cell types (Saos-2 human osteoblast-like cells and HUVEC human umbilical vein endothelial cells), it may be concluded that DBD plasma treatment positively influences cell growth on PET. This effect was found to be connected predominantly with increased surface energy and oxygen content of the surface of treated PET foils.

Flat and nanostructured thin films were fabricated by deposition of ultra-thin (

Magnetron sputtering and gas aggregation sources are commonly used techniques for the preparation of metallic nanoparticles. In this study we compare both of these techniques used for the production of thin Ag nanoparticle films from the point of view of their morphology, topography and optical properties in dependence on the deposition time and substrate material. It is shown that in the case of sputter deposition, the morphology and optical properties of prepared films are dependent on the substrate material and deposition time and the resulting films are smooth with root-mean-square roughness 2 nm. By contrast, films produced using gas aggregation source are considerably rougher (root-mean-square roughness 12 nm) and consist of individual Ag nanoparticles. The deposition time affects in this case only the amount of nanoparticles on the surface and intensity of an anomalous absorption peak.

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.

Nanoscale 10(38), 18275 - 18281 (2018). doi:10.1039/C8NR06155F, Magnetron discharge in a cold buffer gas represents a liquid-free approach to the synthesis of metal nanoparticles (NPs) with tailored structure, chemical composition and size. Despite a large number of metal NPs that were successfully produced by this method, the knowledge of the mechanisms of their nucleation and growth in the discharge is still limited, mainly because of the lack of in situ experimental data. In this work, we present the results of in situ Small Angle X-ray Scattering measurements performed in the vicinity of a Cu magnetron target with Ar used as a buffer gas. Condensation of atomic metal vapours is found to occur mainly at several mm distance from the target plane. The NPs are found to be captured preferentially within a region circumscribed by the magnetron plasma ring. In this capture zone, the NPs grow to the size of 90 nm whereas smaller ones sized 10–20 nm may escape and constitute a NP beam. Time-resolved measurements of the discharge indicate that the electrostatic force acting on the charged NPs may be largely responsible for their capturing nearby the magnetron., Published by RSC Publ., Cambridge

Titanium is one of the most common materials employed for production of implants, which is due to its good biocompatibility. However, the colonization of titanium surface by osteoblast cells may be influenced by its roughness and therefore precise control of roughness of titanium surface as well as identification of its optimal value for growth of cells is of high importance. In this study the nanorough titanium surfaces were prepared on polished disks of TiAlV by two step method of deposition. In the first step TiAlV were coated by nanoparticles generated by gas aggregation sources. Such prepared films of nanoparticles were subsequently covered with a titanium overlayer. Different values of surface roughness in the range 1–100 nm were achieved by variation of the size and number of the nanoparticles. Such prepared surfaces were subsequently used for investigation of influence of roughness of titanium surfaces on the adhesion of human osteoblast-like MG-63 cells. It was found out that 7 days after seeding the highest number of adhering cells was observed for samples with root-mean-square roughness of 30 nm.

Nylon 6,6 foils have been treated by an atmospheric pressure air dielectric barrier discharge. The action of plasma on nylon foils was determined by means of a wide range of techniques that enabled us to study changes in their surface as well as bulk properties. The plasma treatment was found to cause significant changes in morphology, surface chemical composition and wettability of the foils depending on the treatment time. On the other hand, optical, thermal and mechanical properties remained unaffected by plasma treatment even for prolonged treatment duration. In addition, independence of dielectric properties of nylon 6,6 foils of the plasma treatment was observed except for the high temperature region. These results clearly show that air atmospheric plasma treatment is suitable for applications in which modification of surface properties of nylon without alteration of their bulk properties is required.

To gain insight into the deposition and stability of oxygen-containing plasma polymer films, the properties of amorphous oxygenated hydrocarbon (a-C:H:O) plasma polymer coatings deposited from acetone vapors under various experimental conditions are investigated. Apart from the discharge power, the influence of the reactive carbon dioxide (CO2) gas on the structure of the resulting films is studied. It is found by characterization using X-ray Photoelectron Spectroscopy and Fourier-Transform Infrared Spectroscopy that the experimental conditions particularly influence the amount of oxygen in the deposited a-C:H:O plasma polymer films. The O/C elemental ratio increases with increasing amount of CO2 in the working gas mixture (up to 0.2 for 24 sccm of CO2 at 30 W) and decreases with increasing RF discharge power (down to 0.17 for 50 W). Furthermore, the nature of bonds between the oxygen and carbon atoms has been examined. Only low amounts of double and triple bonded carbon are observed. This has a particular influence on the aging of the plasma polymer films which is studied both in ambient air and in distilled water for up to 4 months. Overall, stable a-C:H:O plasma polymer films are deposited comprising low amounts (up to about 5%) of ester/carboxyl groups.

Control of surface wettability is of great importance in a wide range of technological applications. In this study we report on the possibility to cover the full range of surface wetting characters from super-hydrophilic to super-hydrophobic one using plasma polymerization (plasma enhanced chemical vapor deposition) performed with different mixtures of hexamethyldisiloxane/oxygen and in combination with nanoparticle deposition.

In this study we report on the deposition of Pt nanocluster films prepared by gas aggregation source that was operated with argon as working gas. The aim of this study was optimization of deposition process as well as determination of properties of deposited nanocluster films and their temporal stability. It was found that the production of Pt nanoclusters reached maximum value for pressure of 100 Pa and increases monotonously with magnetron current. The deposition rate at optimized deposition conditions was 0.7 nm of the Pt nanocluster film per second. Deposited films were porous and composed of 4 nm Pt nanoclusters. The nanoclusters were metallic and no sights of their oxidation were observed after 1 year on open air as witnessed by X-ray photoelectron spectroscopy. Regarding the electrical properties, a dramatic decrease of the resistivity was observed with increasing amount of deposited nanoclusters. This decrease saturated for the films approximately 50 nm thick. Such behavior indicates transition between different mechanisms of electrical conductivity: charge hopping for thin discontinuous films and current conduction through conducting path formed when higher amount of nanoclusters is deposited. Different mechanisms of electrical conduction for thin and thick layers of Pt were confirmed by subsequent investigation of temperature dependence of resistivity. In addition, no changes in resistivity were observed after one year on open air that confirms stability of produced Pt nanocluster films.

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.

R. f. magnetron sputtering of poly(tetrafluoroethylene) in configuration of a gas aggregation source is shown to produce super-hydrophobic nano-structured coatings in which cross-linked nano-particles of fluorocarbon plasma polymer are embedded in an uncross-linked continuous ( CF 2 ) x matrix. The 20 – 30 nm nano-particles appear in proximity of the magnetron and have cross-linked structure as a result of fast random radical recombination in the plasma. The continuous phase is formed at remote distances from the magnetron as a result of slower step-growth gas phase polymerization of CF 2 bi-radicals. The matrix has highly crystalline structure in which the CF 2 groups tend to adopt a 15/7 helical configuration. At least part of the macromolecules constituting the polymeric phase are oligomers with the molar mass below 1400 g/mol.

Vapor phase deposition of poly(ethylene) is shown to produce uncross-linked thin films consisting of linear (CH2)100 oligomers with narrow molar mass distribution of dispersity DM = 1.10. Early stages of the film formation are characterized by the growth of two-dimensional compact islands of constant 7–8 nm thickness. The transversal evolution of islands is studied in the context of the Dynamic Scaling Theory. The aggregation regime is found to be valid in a narrow range of coverage 0.1