Search

The plasma polymerization of amide-based precursors is a nearly unexplored research area, which is in contrast with the abundance of reports focusing on amide-based surface modification using wet chemistry. Therefore, this study aims to profoundly investigate the near-atmospheric pressure plasma polymerization of N , N -dimethylacrylamide (DMAM) to obtain stable coatings. In contrast to the unstable coatings obtained at lower discharge powers, the stable coatings that were obtained at higher powers showed a lower hydrophilicity as assessed by water contact angle (WCA). This decrease in hydrophilicity with increasing plasma power was found to be related to a reduced preservation of the monomer structure, as observed by Fourier transform infrared (FTIR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and XPS C 60 depth profiling, a rarely used but effective combination of techniques. Furthermore, the chemical composition of the coating was found to be in good agreement with the plasma active species observed by optical emission spectroscopy. Additionally, XPS C 60 depth profiling indicated a difference between the top layer and bulk of the plasma polymer due to spontaneous oxidation and/or postplasma coating deposition. Finally, the stable coatings were also found to have cell-interactive behavior toward MC3T3 as studied by in vitro live/dead fluorescence imaging and (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) (MTS) assays. With the latter technique, a cell viability of up to 89% as compared with tissue culture plates after 1 day of cell culture was observed, indicating the potential of these coatings for tissue engineering purposes.

Plasma polymerization is gaining popularity as a technique for coating surfaces due to the low cost, ease of operation, and substrate-independent nature. Recently, the plasma polymerization (or deposition) of 2-oxazoline monomers was reported resulting in coatings that have potential applications in regenerative medicine. Despite the structural versatility of 2-oxazolines, only a few monomers have been subjected to plasma polymerization. Within this study, however, we explore the near atmospheric pressure plasma polymerization of a range of 2-oxazoline monomers, focusing on the influence of the aliphatic side-chain length (methyl to butyl) on the plasma polymerization process conditions as well as the properties of the obtained coatings. While side-chain length had only a minor influence on the chemical composition, clear effects on the plasma polymerization conditions were observed, thus gaining valuable insights in the plasma polymerization process as a function of monomer structure. Additionally, cytocompatibility and cell attachment on the coatings obtained by 2-oxazoline plasma polymerization was assessed. The coatings displayed strong cell interactive properties, whereby cytocompatibility increased with increasing aliphatic side-chain length of the monomer, reaching up to 93% cell viability after 1 day of cell culture compared to tissue culture plates. As this is in stark contrast to the antifouling behavior of the parent polymers, we compared the properties and composition of the plasma-polymerized coatings to the parent polymers revealing that a significantly different coating structure was obtained by plasma polymerization.

Polymeric scaffolds prepared from polycaprolactone (PCL), PCL-collagen and PCL-elastin were prepared by electrospinning. The scaffolds were coated by plasma polymerization of pyrrole doped with iodine, to improve cellular adhesion and fibroblast proliferation. The morphology, composition, and crystalline structure of the scaffolds were characterized by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy, small- and wide-angle X-ray scattering, thermogravimetric analysis and differential scanning calorimetry. The scaffold fibers had average diameters between 90 and 330 nm before coating. After coating by plasma polymerization, the average diameters increased to between 290 and 530 nm. The presence of elastin and collagen in the fibers was corroborated by infrared spectroscopy. X-ray scattering measurements show that neither elastin nor collagen form crystals in the fiber, while PCL maintains its crystallinity and is not affected by the plasma treatment. Fibroblast cell cultures in the presence of the scaffolds were characterized by viability assays and SEM. The results show that the scaffolds modified with plasma polymerized pyrrole provide a suitable environment for fibroblast adhesion, growth and viability.

Human Mesenchymal Stem cells (hMSCs) are becoming a major focus in biomedical fields. Application of in vitro expanded hMSCs to treat numerous ailments has led to a commercial emphasis on improving hMSC growth ex vivo. Production of substrate independent, novel thin films is one potential tool for production of commercial viable hMSC expansion. Plasma polymerization allow controlled chemical optimisation of large scale surface areas in a substrate independent manner. Previous study shown that plasma polymerized Furfuryl Methacrylate (ppFMA) surfaces allowed primary fibroblast cells adhesion and proliferation. However, under some deposition conditions, particle aggregates formation was observed. These aggregates had the effect of disrupting cell attachment, despite being chemically indistinguishable from the underlying surface. Herein, hMSCs were cultured on ppFMA surfaces to determine their suitability for stem cell culture and observe the effect of particle aggregates on hMSC attachment and growth. Both metabolic and DNA quantification assays showed that surfaces with particle aggregates had lower numbers of attached cells and slower growth. Uniform surfaces without aggregates showed higher cell attachment and growth levels, which were comparable to Thermanox. Phenotypic analysis showed that there was no change to hMSCs phenotype after 7 & 14days of culture on uniform ppFMA surface. Further investigation using time-lapse image analysis indicated that particle aggregates reduced cell attachment by presenting a physically weak boundary layer, which was damaged by intracellular tension during cell spreading. ppFMA surface can provide a stable substrate independent hMSCs expansion interface that could be applied to larger scale bioreactors, beads or scaffolds., (Copyright © 2017 Elsevier B.V. All rights reserved.)

This study investigates the application of Plasma-polymerized pyrrole (ppPY) as bioactive platform for DNA immobilization and cell adhesion based on the fundamental properties of ppPY, such as chemical structure, electrochemical property, and protein adsorption. Variations in electrochemical properties of the ppPY film deposited under different plasma conditions before and after DNA immobilization were measured using electrochemical impedance spectroscopy (EIS). The equilibrium concentration of the probe DNA immobilized on the ppPY surface was deduced by detecting the variations in the surface charge transfer resistance (Rct ) of the ppPY films after DNA immobilization with different concentrations. In addition, the detection limit of the target DNA hybridization with probe DNA, the association constant, Ka , and the dissociation constant were deduced from Langmuir isotherm equations simulated using the experimental data collected by EIS. Moreover, inverted microscope was used to observe the cell adhesions onto the surface of the ppPY films prepared under different plasma conditions. Different adhesive behaviors of cells were observed, demonstrating that ppPY films could be an alternative biomaterial used as the sensitive layer for DNA sensor or cell adhesion., (Copyright © 2013 Wiley Periodicals, Inc.)

Thin plasma polymer films from ethylenediamine were deposited on planar substrates placed on the powered electrode of a low pressure capacitively coupled 13.56 MHz discharge. The chemical composition of the plasma polymer films was analyzed by Fourier Transform Infrared Reflection Absorption Spectroscopy (FT-IRRAS) as well as by X-ray photoelectron spectroscopy (XPS) after derivatization of the primary amino groups. The PPEDA films undergo an alteration during the storage in ambient air, particularly, due to reactions with oxygen. The molecular changes in PPEDA films were studied over a long-time period of 360 days. Simultaneously, the adhesion of human osteoblast-like cells MG-63 (ATCC) was investigated on PPEDA coated corundum blasted titanium alloy (Ti-6Al-4V), which is applied as implant material in orthopedic surgery. The cell adhesion was determined by flow cytometry and the cell shape was analyzed by scanning electron microscopy. Compared to uncoated reference samples a significantly enhanced cell adhesion and proliferation were measured for PPEDA coated samples, which have been maintained after long-time storage in ambient air and additional sterilization by γ-irradiation., (Copyright © 2013 Elsevier B.V. All rights reserved.)

The achievement of large-scale applications of plasma-based polymers in biomedical sectors does not satisfy the appropriate level although a substantial amount of research is already performed. In this context, further investigations are necessary to design and synthesize plasma polymers for biomedical applications. Among the polymeric materials, plasma-based polymers have attracted substantial attention owing to their numerous advantages like faster processing, lower costs, eco-friendly waste, biocompatibility, and versatility, making them excellent materials for biomedical applications. Further, polymer synthesis using plasma polymerization techniques can avoid the time-consuming conventional multistep synthesis procedure. Plasma polymerization also offers a significant solution to overcome the numerous difficulties in the traditional approach where polymers can be directly attached to the desired surface using a plasma process, without disturbing the growing chain, and, thus, prevent an additional process such as grafting. Nevertheless, the design of appropriate plasma-based synthesis methods, optimization of the plasma process parameters, and exploration of polymer-based biocompatibility approaches are still challenging research areas. Regarding the surface morphological features of these plasma polymers, they possess several characteristics, such as wettability, adhesion capacity, and so on, that are important considerations in biomedical applications. In this review, numerous recent approaches to plasma polymerization methods along with different precursor phases used for such kind of synthesis of polymeric materials are discussed. The morphological aspect of the synthesized plasma polymers connected with biomedical applications is also reported in this review. Finally, promising aspects of plasma polymers for biomedical applications are briefly reported in this work. This review may offer an extensive reference for upcoming perceptions of plasma-based polymers and their applications in biomedical sectors. [ABSTRACT FROM AUTHOR]

This work compared C4F8 and C4H2F6 gases (as third components in CF4 + He gas mixture) for the high aspect ratio etching of SiO2 through the amorphous carbon layer (ACL) mask. The research scheme included the study of gas‐phase plasma characteristics, etching kinetics, and etching profiles. It was found that CF4 + C4F8 + He and CF4 + C4H2F6 + He gas mixtures are featured by quite close plasma parameters, the kinetics of electron‐impact processes, and ion bombardment intensities. At the same, the use of C4H2F6 provides a bit lower F atom density together with a bit higher polymerizing ability. All these factors cause lower absolute etching rates for both SiO2 and ACL but provide better SiO2/ACL/ACL selectivity and profile features. [ABSTRACT FROM AUTHOR]

Molecularly imprinted polymers (MIPs) are synthetic polymers that mimic the functions of antibodies. Though MIPs are promising tools in various areas, achieving high selectivity in MIPs can be difficult. To improve selectivity, various approaches have been implemented; however, the role of polymerization methods or synthetic techniques in enhancing the selectivity of MIPs has not been studied and remains a crucial area for further research. MIPs are typically prepared from free radical reactions. Recently, we found that Dielectric Barrier Discharge (DBD) plasma can be used to initiate the polymerization of vinyl monomers. The DBD plasma method allows the monomers to associate with the template molecules and initiate polymerization with minimal disruption to the positioning of the monomers. We hypothesize that this could be a preferred method to prepare MIPs over the traditional radical reaction that may cause a disturbance of the pre-associated monomers on the templates for the polymerization. Chicken egg white serum albumin (CESA) was used as the template protein for the MIPs. Our results show that in all test conditions, approximately twofold improvement in selectivity was achieved, which is the primary performance metric for MIPs. This enhancement was evident across all categories, including MIPs prepared from various monomer combinations. [ABSTRACT FROM AUTHOR]

Atmospheric‐pressure plasma‐enhanced film deposition with single‐filament dielectric‐barrier discharges (DBDs) in argon was investigated using allyltrimethylsilane (ATMS) as a precursor. Nonionic deposition in the discharge zone is largely precluded by a rapid cross‐flow of the source gas, containing between 50 and 2000 ppm of ATMS. The performed experimental studies show a surprisingly large deposited film mass per transferred elementary charge between 220 and 540 amu. Film growth experiments, mass‐spectrometric studies, and kinetic considerations led to the conclusion that the deposition process is a cationic surface polymerization, initiated by ions produced in the DBD by energy transfer from long‐lived excited Ar species and propagated by addition of ATMS monomer molecules. [ABSTRACT FROM AUTHOR]

The electrophysical parameters of the plasma and the kinetics of plasma-chemical processes in a CF4 + H2 + Ar mixture while varying the CF4/H2 ratio are studied. When using diagnostic methods and plasma modeling together, it is found that replacing tetrafluoromethane with hydrogen (a) leads to a decrease in the plasma density and an increase in electronegativity; and (b) it causes a disproportionately sharp drop in the concentration of fluorine atoms. The reason for the latter effect is the increase in the frequency of the death of atoms in reactions of the CHFx + F → CFx + HF type initiated by heterogeneous recombination via the CFx + H → CHFx mechanism. The simultaneous increase in the concentration of polymer-forming CHxFy (x + y < 3) radicals indicates an increase in the polymerization load of the plasma on the surfaces in contact with it. [ABSTRACT FROM AUTHOR]

Current interest in dispersion strategies for nanoparticle fillers is driving research into covalently attached polymer brushes. The primary need for these "hairy nanoparticles" is for testing and developing new technologies based on polymer nanocomposites. To that end, we have prepared polymer nanocomposites with covalently tethered chains on a naturally occurring montmorillonite clay template via a metal-mediated surface-initiated ring opening metathesis polymerization approach. The nanocomposites were characterized in terms of polymer:clay composition and of various chain architecture parameters such as molecular weight, polydispersity index, and grafting density. [ABSTRACT FROM AUTHOR]

In this work, the probe system developed by us earlier for plasma diagnostics under the conditions of plasma polymerization and synthesis of carbon nanostructures was constructively developed. The probe system is supplemented with a block that allows cleaning the probe with ion current, as well as obtaining the second derivative of the probe current-voltage characteristic by the harmonic method. The probe system was tested on the example of plasma diagnostics in a mixture of He + 0.1% CH4. [ABSTRACT FROM AUTHOR]

Medical devices are often vulnerable to colonization by nosocomial pathogens (bacteria), leading to infections. Traditional sterilization methods may not always be effective, and as a result, alternative options are being explored to prevent microbial contamination. Recently, scientists are emphasizing using plant-derived essential oils that possess inherent antibacterial properties to produce antimicrobial coatings using plasma polymerization technology carried out at atmospheric pressure (AP). This approach shows promise compared to other coating strategies that need several processing steps, including a high-vacuum system, and are laborious, such as the immobilization of antimicrobial materials on precoated layers in the low-pressure plasma polymerization approach. The present study demonstrates the potential of AP plasma polymerization for producing thin films with excellent antibacterial properties and surface characteristics. The resulting coatings are stable, smooth, and have high wettability, making them ideal for repelling bacteria. The calculated zeta potential and deposition rate for the films are also favorable. These AP plasma-polymerized thin films created from carvone show a reduction rate of more than 90% for Escherichia coli and Staphylococcus aureus bacteria. Our computational docking studies also reveal strong binding interactions between the original carvone monomer and both bacteria. The study suggests that these AP plasma-produced coatings have great potential as antibacterial coatings for biomedical devices. [ABSTRACT FROM AUTHOR]

Finding proper strategies to control plasma polymerization processes is a crucial aspect to produce thin films with tailored characteristics. In this work, the validity of the Yasuda parameter W/FM (W: discharge power and FM: precursor feed rate) as a controlling parameter for a polymerization process assisted by an atmospheric pressure single electrode plasma jet and the aerosolized fluorinated silane precursor trimethoxy(3,3,3‐trifluoropropyl)silane is demonstrated. The properties of thin films deposited under different W/FM values are discussed using attenuated total reflectance—Fourier transform infrared (ATR‐FTIR) spectroscopy, X‐ray photoelectron spectroscopy (XPS), water contact angle (WCA) measurements, and scanning electron microscopy (SEM). Results suggest the presence of two deposition domains as a function of W/FM (an energy‐deficient domain and a monomer‐deficient domain), each inducing coatings with different chemical and physical properties. Furthermore, coatings deposited under the same W/FM values exhibit similar characteristics regardless of the power and feed rate values adopted. Considering the potential use of the deposited coatings to increase the antiadhesive properties of implantable medical devices, preliminary results on coatings' antiadhesive activity against Pseudomonas aeruginosa and Staphylococcus aureus are presented. [ABSTRACT FROM AUTHOR]

This study aimed to characterize the immobilization of the novel JIChis-2 peptide on the Ti-6Al-4V alloy, widely used in the biomedical sector. The antimicrobial activity of JIChis-2 was evaluated in the Gram-negative bacterium E. coli. Its immobilization occurred by inducing the formation of covalent bonds between the N-terminus of the peptides and the surface previously submitted to acrylic acid polymerization via the PECVD technique. Coated and uncoated surfaces were characterized by FTIR, AFM, SEM and EDX. Studies of global and localized corrosion were carried out, seeking to explore the effects triggered by surface treatment in an aggressive environment. Additionally, the ability of the functionalized material to prevent E. coli biofilm formation evidenced that the strategy to immobilize JIChis-2 in the Ti-6Al-4V alloy via PECVD of acrylic acid resulted in the development of a functional material with antibiofilm properties. [ABSTRACT FROM AUTHOR]

In this study, we describe an atmospheric pressure plasma jet (APPJ) device made of four-bore tubing operable in inhospitable humid environments and introduce two potential applications of liquid material processing: decomposition of aqueous phosphorus compounds and solution-plasma polymerization. A four-bore tube was used as the plasma transfer conduit and two diagonal bores contained metal wires. In the proposed APPJ device, the metal wires serving as electrodes are completely enclosed inside the holes of the multi-bore glass tube. This feature allows the APPJ device to operate both safely and reliably in humid environments or even underwater. Thus, we demonstrate that the proposed electrode-embedded APPJ device can effectively decompose aqueous phosphorus compounds into their phosphate form by directly processing the solution sample. As another application of the proposed APPJ device, we also present the successful synthesis of polypyrrole nanoparticles by solution plasma polymerization in liquid pyrrole. [ABSTRACT FROM AUTHOR]

In the current study, plasma-polymerized methyl methacrylate (PP-MMA) generation on the inner surface of a silicone tube was performed in a capacitively coupled discharge reactor. The possibility of generating plasma inside the tube was analyzed and calculated by using optical emission spectroscopy (OES). A hollow cathode model was first proposed to determine whether plasma discharge would be generated inside the tube in the low-pressure regime. Since the ignition of plasma inside the tube is necessary for the initiation of polymerization processes, the sheath thickness was calculated analytically. To achieve the goal, the electron temperature and density of plasma should be determined beforehand. In this study, the electron temperature and plasma density were measured and calculated according to OES spectra using both the modified Boltzmann plot and the line-ratio method. The results reveal that the occurrence of plasma inside the tube can be achieved if the tube's inner diameter is greater than two times the thickness of the sheath. The effect of methyl methacrylate (MMA) monomer concentration on sheath thickness, and, hence, plasma generation and deposition, was investigated in the presence of argon plasma and MMA monomer. According to the study, one could control the ignition of plasma discharges inside the tube followed by plasma polymerization deposition. The OES method was also applied to identify the presence of the excited species related to the fragmented monomer. The deposition of PP-MMA films on the inner surface of the tube was confirmed via attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy. [ABSTRACT FROM AUTHOR]

Acrylamide polymerization in solution was successfully induced by high‐voltage atmospheric cold plasma (HVACP) treatment, using nitrogen gas. Addition of metal sulfates greatly increased acrylamide polymerization, with ZnSO4 and MgSO4 yielding 89% and 62% polyacrylamide polymer, respectively. Presence of excited nitrogen species during HVACP treatment was demonstrated using optical emission spectroscopy. Proton NMR (H1NMR) and attenuated total reflectance‐Fourier transform infrared spectroscopy were performed to verify the degree of polymerization. Rheology experiments and viscosity measurements showed that acrylamide samples treated with HVACP in the presence of ZnSO4, MgSO4 had higher viscoelastic moduli, and intrinsic viscosity (η) compared to those treated in deionized (DI) water, due to the higher degree of polymerization. Addition of ZnSO4 yielded the greatest viscoelastic moduli and intrinsic viscosity (the storage modulus was G' = 1.26·104 ± 1.8·103 Pa and the loss modulus was G" = 3.06·103 ± 1.10·103 Pa, and [η] ≈ 26 L/g). With MgSO4, the viscoelastic moduli were G' = 5.93·103 ± 1.40·103 Pa and G" = 1.60·103 ± 2.6·102 Pa, and (η) ≈ 4.7 L/g. In DI water G' = 1.55·103 ± 2.1·102 Pa and G" = 7.44·102 ± 1.37·102 Pa, and (η) ≈ 2. PAM prepared with ZnSO4 also had the highest molecular weight, as determined by mass spectroscopy. ZnCl2 and MgCl2 hindered acrylamide polymerization, highlighting the effect of the sulfate ions on acrylamide polymerization using HVACP treatment. [ABSTRACT FROM AUTHOR]

This study investigated the plasma polymerization process of butane in a closed radio frequency plasma reactor system. Optical emission spectra of the luminous gas phase specified the main plasma species in the plasma system are radical species of CH and H (Balmer series). In the early stage of the butane plasma polymerization process, dissociation glow (cathode glow) was the primary glow with much higher deposition rate observed due to the availability of CH radicals in the system. In the late stage of the plasma process, in contrast, negative glow dominated and plasma deposition rate significantly decreased and eventually stopped due to exhaustion of the film forming CH radicals as confirmed by OES spectra of the luminous plasma phase. The results indicate that dissociation glow in the discharge creates hydrocarbon species for plasma polymeric film deposition. [ABSTRACT FROM AUTHOR]

The properties of the final product resulting from plasma polymerization strongly depend on the operating conditions and they impact the final application of the plasma polymer coating. Low‐pressure pulsed plasma polymerization of maleic anhydride was investigated at two different positions in relation to the glow discharge in a 1‐m‐long tubular reactor. Interestingly, competition was observed in the deposition of maleic anhydride plasma polymer in the form of a smooth thin film versus that in the form of nanoparticles. The possibility of a spatiotemporal control of plasma polymerization enabled the deposition of a plasma coating with tunable morphological properties depending on the sample position from the glow discharge and on the plasma pulse parameters (on‐time and off‐time). [ABSTRACT FROM AUTHOR]

Biofilms pose important economic and health risks in biomedical applications and in food industries. In this study, coatings that reduce the biofilm formation of Pseudomonas aeruginosa on polystyrene cell culture plates are deposited by plasma polymerization of (3‐aminopropyl)triethoxysilane using an atmospheric pressure plasma jet system at three different power levels. Surface characterizations and quantification of biofilm formation during 1 week after deposition suggest that the higher concentration of oxygenated carbon groups on the coated samples than on uncoated ones can induce higher levels of oxidative stress in the bacteria in contact with the coatings. This causes an initial overproduction of extracellular polymeric substances that can avoid further bacterial attachment and biofilm formation at later cycles of biofilm development. [ABSTRACT FROM AUTHOR]

Superhydrophobic (SH) surfaces have great potential in numerous applications. Plasma polymerization is one of the most efficient technologies for engineering SH surfaces due to its unique feature of tailoring surface chemistry and surface topography simultaneously. Herein, a novel sandwich‐like plasma device that consists of contiguous two‐stage dielectric barrier discharges (DBDs) driven by the time‐modulated radiofrequency (RF) and pulsed power sources is proposed to polymerize hexamethyldisilazane (HMDSN) at atmospheric pressure for the purpose of SH surface engineering. The coordination of dual power sources shows effective performances in plasma operation and material surface treatment, compared to the case driven by any power source alone. Easy ignition and enhanced stability are achievable for the upper RF DBD with the assistance of the bottom pulsed DBD. Vice versa, a diffuser pulsed discharge is obtainable with the input of abundant active and energetic species and precursor fragments from the upper RF plasma. Diagnostic measurements by optical emission spectroscopy and Mie scattering demonstrate that HMDSN fragmentation and nanoparticle nucleation are initiated predominantly by the RF‐driven plasma. These species and nanoparticles are further fragmented and dispersed in the bottom pulsed discharge. Consequently, the desired SH surface is fabricated with a similar pattern to that of the pulsed DBD geometry. This study provides a new pathway based on the plasma‐assisted method to control surface hydrophobicity and provides insights on a new plasma deposition method suitable for atmospheric pressure material processing. [ABSTRACT FROM AUTHOR]

The chemical properties of plasma polymers strongly depend on the operating conditions of plasma polymerization and impact their final application. Low‐pressure pulsed plasma polymerization of maleic anhydride was investigated at different positions from the glow discharge in a unique 1‐m‐long reactor. Based on a macroscopic approach, the growth kinetics of maleic anhydride plasma polymerization was investigated, leading to the identification of three growth regimes. The calculation of apparent activation energies associated with each regime and each position and the chemical characterization of polymer films by X‐ray photoelectron spectroscopy and attenuated total reflection–Fourier‐transform infrared as well as optical emission spectroscopy analyses of plasma species formed during deposition strongly indicate a combined spatial and temporal influence on the plasma polymerization kinetics. [ABSTRACT FROM AUTHOR]

Solution‐based amine absorption technologies have been widely applied for CO2 capture, but they have several drawbacks. This paper reports on the synthesis of the first solid‐state amine adsorbent prepared through a simple plasma polymerization and deposition on physicochemically modified natural mordenite–clinoptilolite zeolite. The plasma deposition of amine polymer under certain conditions resulted in a significant increase in surface area‐weighted CO2 adsorption capacity as the natural zeolite. The strength of the interaction between CO2 and the adsorbent was weaker for the plasma polymer‐modified zeolite than without the plasma coating, which may facilitate regeneration. Both indications make the amine plasma polymer‐based zeolite adsorbent a good candidate for CO2 adsorption and separation. [ABSTRACT FROM AUTHOR]

In this study, an atmospheric‐pressure nanosecond impulse discharge initiated above the pyrrole microemulsion surface is applied to polymerize pyrrole and obtain a polypyrrole film. The films obtained under different number of plasma discharge times and duration of argon gas input time are investigated using a field emission scanning electron microscope. Results show that the roughness and thickness of the polypyrrole film can be tuned by controlling discharge times and the gas feed time. Four‐point sheet resistance measurements of the films reflect that those with a smoother and more complete surface have better electrical conductivity. The films are identified as polypyrrole by Fourier‐transform infrared spectroscopy, X‐ray diffraction, and X‐ray photoelectron spectrometry. Also, N2 is a critical factor in polymerizing polypyrrole and the gas–liquid plasma polymerization mechanism, which has three steps, is discussed. [ABSTRACT FROM AUTHOR]

The key processes in an atmospheric‐pressure plasma jet containing Ar and tetraethyl orthosilicate (TEOS) are studied by means of two‐dimensional imaging of the important discharge radicals: OH, CH, and atomic O. The kinetics of the species generation is investigated by laser‐induced fluorescence spectroscopy. The work is focused on the behavior of the ground‐state radicals' density as a function of the applied voltage and of the Ar/TEOS mixing ratio. First insights on the physicochemical mechanisms of precursor fragmentation are provided. The influence of precursor admixture and precursor fragmentation on the OH, CH radicals, and atomic oxygen kinetics is revealed. The dominant role of gas‐phase oxidation processes in CH radical formation and polymerization is discussed and analyzed. [ABSTRACT FROM AUTHOR]

In this paper, plasma enhanced chemical vapor deposition (PECVD) of acrylic acid (AA) was employed as a one-step and solvent-free technique to prepare durable organic anti-fogging coatings on mirror and glass surfaces. The effects of important PECVD parameters including substrate temperature and plasma power on the deposition kinetics, as well as on the structural and morphological properties of the as-deposited films were investigated. Employing a low substrate temperature (5 °C) and a high plasma power (30 W) combination resulted in the highest observed deposition rate of 27.7 nm/min. Fourier-transform infrared (FTIR) spectroscopy showed high structural resemblance between PECVD-PAA and reference poly(acrylic acid) (PAA). The PAA-deposited surfaces showed excellent and durable anti-fogging performance without any loss in their optical transparencies. Successive antifogging tests showed that the PAA thin film exhibited high functional durability without delamination, indicating that it can be used in real-world applications. • PECVD is a one-step and solvent-free technique to deposit poly(acrylic acid). • Poly(acrylic acid) thin film deposited by PECVD possess anti-fogging functionality. • High PAA deposition rates can be achieved at low substrate temperatures in PECVD. • PAA-deposited surfaces show excellent and durable anti-fogging performance. [ABSTRACT FROM AUTHOR]

Temperature-responsive films of poly(N-isopropylacrylamide) (PNIPAM) were facilely fabricated by one-step plasma-initiated polymerization and then functionalized by self-polymerization of dopamine on the surface. High retention of the monomer structure and temperature-responsive properties in PNIPAM films were confirmed. After plasma-initiated polymerization, PNIPAM films formed protrusions and ridges surfaces. Moreover, cross-linker of N,N′-methylenebisacrylamide with different dosage was introduced into the systems to effectively modulate the roughness of PNIPAM films and to supply better adhesive surface. Furthermore, in cell culture, satisfactory survival rate of the attached Hela cells was obtained on PNIPAM films, and the cell viability was improved further on PNIPAM/PDA films. The results indicated that such films might be applicable in medical treatment and tissue engineering, due to their adjusted adhesion ability and less toxicity to cells. [ABSTRACT FROM AUTHOR]

Titanium implants have been widely used for orthopedic and trauma surgery, while they often encounter the predicament of implant-associated infection, which leads to surgery failure. To address this issue, polycation surface coatings that are able to improve the antibacterial properties of implants have been developed. The objective of this study is to fabricate amine cationic polymer onto the surface of titanium alloys via a combination of plasma polymerization and layer-by-layer assembly and to investigate their antibacterial property after implantation. Titanium alloys were coated with poly(allylamine) (PAA) as the first polycationic monolayer via plasma polymerization. The obtained PAA-coated titanium alloys were then assembled with multilayers of anionic poly(sodium 4-styrenesulfonate) (PSS) and cationic poly(allylamine hydrochloride) (PAH) through layer-by-layer (LbL) self-assembly. Surface characterization using scanning electron microscopy, contact angle measurement, atomic force microscopy and X-ray photoelectron spectroscopy confirmed the successful multilayer coatings of PAA, PSS and PAH onto the surface of titanium alloys. Such amine cationic polymer-coated titanium alloys exhibited a negligible in vitro cytotoxicity, while showed an effective antibacterial property against Escherichia coli and Staphylococcus aureus. In addition, no neutrophil distribution was observed between the implanted amine cationic polymer-coated titanium alloys and tissues, which suggested in vivo antibacterial property. These multilayer coated titanium alloys were able to minimize the implant-related infection and showed a great promise for bioimplantation. [ABSTRACT FROM AUTHOR]

Using atomic force microscopy, the evolution of the morphology of island poly(p-xylene) films formed on silicon substrates by vapor deposition polymerization at two deposition temperatures of +23 and 0°C and a fixed monomer flow is studied. The dependences of the surface coverage, the effective thickness of the island coating, and the density and average size of the polymer islands on the deposition time are investigated. Within the framework of the dynamic scaling theory, the size distribution of islands and the size distribution of their capture zones are analyzed. It is shown that the observed features of the evolution of the morphology of island poly(p-xylylene) films cannot be fully described in the framework of classical models based on diffusion-limited aggregation. However, they can be explained by the reversibility of aggregation, which is a specific feature of the polymeric nature of the island coatings being formed. [ABSTRACT FROM AUTHOR]

Atmospheric plasma treatment followed by a plasma polymerisation coating produced an aluminium surface having high water repellency and icephobicity. We varied the plasma parameters and the amount of hexamethyldisiloxane precursor to optimise surface hydrophobicity. The static contact and sliding angles of the surface reached 163° and <1°, respectively. Furthermore, the prepared surfaces remained superhydrophobic after seven days of immersion in acid--base media as well as after five icing/de-icing cycles. [ABSTRACT FROM AUTHOR]

Highlights • Functional plasma polymer was prepared on electrospun polymer nanofibrous mat. • Plasma polymerization run at atmospheric pressure in Ar/maleic anhydride/C 2 H 2 mixture. • Anhydride/carboxyl plasma polymer thin films coated uniformly the polymer nanofibers. • The coating penetrated deep into the nanofibrous mat. Abstract This work investigates for the first time the penetration depth, nanoscopic homogeneity and conformality of the plasma polymerization onto an electrospun nanofibrous mat. The study is carried out on the model example of atmospheric pressure plasma co-polymerization of anhydride-rich films onto polycaprolactone mats that can find a significant practical applications, for example in tissue engineering and regenerative medicine. Since the surface-to-volume ratio of nanofibrous mats is enormous and the structure of mats resembles extracellular matrix the successful plasma coating of each whole fiber and understanding the penetration of the polymerization into the mat structure are extremely important. The films with reactive anhydride groups were prepared by co-polymerization of maleic anhydride and acetylene using dielectric barrier discharge. The studies were accompanied by the quantification of anhydride groups directly on the PCL electrospun mat using the chemical derivatization with trifluoroethylamine and X-ray photoelectron spectroscopy. The nanoscopic homogeneity and conformality of the anhydride plasma polymer coating on the front side and backside of the nanofibrous mat, 30–40 μ m in thickness, did not differ according to the dynamic SIMS mapping. The films containing approximately 6 anhydride groups per 100 carbon atoms coated homogeneously the nanofibers deeper in the PCL mat. The characteristic penetration depth of the deposition was estimated as 46 ± 5 μ m. [ABSTRACT FROM AUTHOR]

Presents a study which prepared and examined the electrical properties of polymeric tetracyanoquinodimethane and tetracyanoethylene films by plasma polymerization. Experimental details; Results; Discussion.

[Display omitted] • A 3D view in plasma polymerization is crucial for coating functional materials. • HMDSO yields plasma film-forming species with different sticking probabilities. • Surface oxidation is relevant in plasma polymerization for complex geometries. Hexamethyldisiloxane (HMDSO) low-pressure plasmas are known for their versatility in the deposition of plasma polymer films (PPFs) with different properties and applications. Although they have been studied for decades, the reaction mechanisms of plasma polymer formation leave open questions, particularly when deposition on 3D materials with complex geometries such as cavities and undercuts is considered. In the present study, two configurations named "cavity" and "undercut" have been selected to study the influence of diffusion of film-forming species and surface reactivity in HMDSO plasmas without and with O 2 admixture. A varying spatial chemical composition of the plasma polymer deposit along the penetration depth of the studied configurations indicates different sticking probabilities of the film-forming species. Furthermore, although ion-induced effects are usually only considered for direct plasma exposure, the obtained results and additional etching experiments reveal that the contribution of high-energy particles might still be considered underneath small openings. Finally, the relevance of oxidizing chemical reactions at the surface inside the configurations is clarified when O 2 is added to the plasma. [ABSTRACT FROM AUTHOR]

[Display omitted] • Development of substrate-independent coatings with controllable surface chemistry. • HMDSO plasma polymerization on PCL-PLGA nanofibers without fiber damage. • APTES silanization of HMDSO-based coatings makes primary amine containing surfaces. • Improvement in cell-material interactions by APTES silanized coatings on nanofibers. Surface modification of hydrophobic nanofibers (NFs) to introduce cell-interactive chemical functionalities remains a challenge in biomedical applications. This study presents a novel three-step plasma-based method for synthesizing coatings with improved chemical selectivity compared to conventional plasma polymers. The process involved hexamethyldisiloxane (HMDSO) plasma polymerization followed by helium plasma activation, both performed in a medium-pressure dielectric barrier discharge. Scanning electron microscopy analysis demonstrated that the plasma-based steps did not cause damage to the NFs. X-ray photoelectron spectroscopy (XPS) and water contact angle measurements revealed the formation of a hydrophilic silanol-rich layer after HMDSO plasma polymerization and helium plasma activation. In the third step, (3-aminopropyl)triethoxysilane (APTES) was grafted onto the plasma polymer to introduce primary amine groups onto the surface, as confirmed by XPS. Although the APTES-based layer exhibited partial removal when exposed to aqueous environments, a stable aminated layer remained on the NF surface, which significantly enhanced Schwann cell responses compared to untreated and HMDSO-based coated NFs. This enhancement was confirmed through fluorescent imaging using live-dead staining, immunostaining, and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. These coatings with a high selectivity in their chemical functionality (amines, or other functionalities via silanization agent selection), offer a promising surface functionalization approach for tissue engineering scaffolds. [ABSTRACT FROM AUTHOR]

Abstract Oxygen rich organic coatings are synthesized in a dielectric barrier discharge at atmospheric pressure. The critical effect of the precursor structure on the final chemical and physical properties of the synthesized coatings and the plasma characteristics are reported. A correlation is proposed between the electrical, optical emission spectroscopy and atmospheric mass spectrometry (MS) measurements of the plasma phase with the chemical properties of the synthesized films. It is shown that the addition of a precursor in an argon plasma leads to a stabilization of the discharge, critically dependent on the precursor structure itself. Different polymerization pathways are evidenced for the saturated and unsaturated precursors by the monitoring of some specific fragments by MS. The polymerized coatings are also characterized with X-Ray Photoelectron Spectroscopy, Infrared Spectroscopy and Atomic Force Microscopy. The presented results not only evidence a stronger preservation of the precursor structure with double bonds in the plasma phase but also reveal the essential role of the distance separating the unsaturation and a function of interest. Highlights • Double bonds in organic precursors modify the electrical behaviour of an atmospheric DBD • Double bonds in organic precursor induce a specific polymerization pathway in the plasma phase • A specific fragment for polymerization is evidenced when double bonds are present • The position of the double bond is of crucial importance in the preservation of the precursor chemistry [ABSTRACT FROM AUTHOR]

Abstract Plasma-polymerized silicon oxynitride (SiO x N y) oxygen barrier thin film was deposited on polyethylene terephthalate substrate by plasma enhanced chemical vapor deposition at low temperature. The deposition reactor utilizes capacitively coupled plasma operating at radio frequency (13.56 MHz). Nitrogen incorporation during the polymerization leads to a SiO x N y dense film with low defects which assists to improve the oxygen barrier properties. The gas mixture of tetraethyl orthosilicate as organosilicon precursor with oxygen and nitrogen gases was used to deposit the transparent polymerized SiO x N y thin films. The effects of nitrogen flow rate on deposition rate, refractive index, surface morphology, surface wettability, chemical structure and binding composition and oxygen permeability of the barrier films were investigated. Moreover, the plasma parameters were monitored by optical emission spectroscopy. SiO x N y oxygen barrier films showed 89–91% transparency. Under the optimal deposition conditions the minimum oxygen permeability of 0.08cm3/cm2day bar was obtained. Highlights • Oxygen barrier films are obtained in low RF power and low temperature. • Transparent gas barrier is obtained which makes it possible to check inside a package. • Nitrogen content, ordered structure and low impurity led to very low O 2 permeability. • Low value O 2 permeability achieved which is favorable for OTFTs and drug packaging. • The lowest value of O 2 permeability obtained is 0.08cm3/cm2day bar. [ABSTRACT FROM AUTHOR]

Atmospheric pressure plasma jet polymerization of methyl methacrylate (MMA) was performed in order to deposit a PMMA-like coating on ultrahigh molecular weight polyethylene (UHMWPE). This study is a first step in the transfer from MMA plasma polymerization experiments previously performed in a dielectric barrier discharge (DBD) reactor to a newly designed atmospheric pressure plasma jet. In this novel plasma setup, the substrate is not directly exposed to the plasma region, but placed in the plasma jet afterglow. The effect of several plasma jet process parameters on the coating properties was investigated using different surface characterization techniques such as XPS, FTIR, AFM, and OPS. Results show that the stationary deposition of PMMA-like thin films results in a radial gradient in surface chemistry, surface morphology, and coating thickness. Additionally, the coating properties were found to significantly depend on the monomer-containing gas flow rate. This observation is also confirmed by CFD modeling, which shows that the monomer-containing gas flow rate strongly influences the gas flow pattern of the plasma afterglow and therefore the final properties of the deposited PMMA-like film. [ABSTRACT FROM AUTHOR]

To enhance the adhesion and polymerization of lipase‐plasma‐polymerized‐ethylene (lipase‐PPE) coatings deposited by aerosol‐assisted atmospheric plasma deposition (AAAPPD), the effects of voltage, ceramic‐dielectric thickness, and pre‐coated PPE layer were investigated. In AAAPPD system, ethylene and lipase‐phosphate‐buffered‐saline aerosol were used as precursors to polymerize ethylene and embed lipase simultaneously. The deposited lipase‐PPE coatings were analyzed with FTIR, SEM, and surface profiler. The results show that increasing voltage from 3 to 4 kV and decreasing ceramic‐dielectric thickness from 1 to 0.38 mm improved the coating adhesion and polymerization. Also, depositing a PPE layer with high energy prior to lipase‐PPE coating enhanced adhesion. These improvements of the biomolecule‐PPE coatings facilitate further bioapplications of this new biomolecule‐embedding method. [ABSTRACT FROM AUTHOR]

[Display omitted] • HEMA:DEAEMA hydrogel synthesis by atmospheric-pressure plasma polymerization. • One-step environmentally friendly polymerization synthesis. • Simultaneous surface microstructuration by plasma polymerization. • Surface charge of hydrogels changes when exposed to solutions of different pH. • Tunable chemical and physical properties by varying the HEMA:DEAEMA mixture ratio. The simple, direct fabrication of pH-responsive hydrogel coatings with microstructured wrinkles from a monomer mixture containing 2-hydroxyethyl methacrylate and 2-(diethylamino)ethyl methacrylate, grafted on silicon substrates via atmospheric-pressure plasma polymerization is reported. The process allows the synthesis of hydrogels with high conversion degree, which preserve the functionalities of both monomers as proven by XPS and FT IR analysis. Atomic force microscopy was conducted to characterize the wrinkle dimension, which revealed an increase of the wrinkle wavelength λ and amplitude A with the film's thickness. The chemical and morphological properties of the hydrogel films are preserved, even after immersion in deionized water for several days, indicating the high stability of the plasma-polymerized hydrogels. The simplicity of atmospheric-pressure plasma polymerization to deposit responsive hydrogels which are highly stable and having tunable properties as "materials on demand", will certainly extend the applications of plasma-based hydrogels especially for biomedical applications. [ABSTRACT FROM AUTHOR]

Although polymerized aniline (polyaniline, PANI) with and without iodine (I2) doping has already been extensively studied, little work has been done on the synthesis of PANI films using atmospheric pressure plasma (APP) deposition. Therefore, this study characterized pure and I2-doped PANI films synthesized using an advanced APP polymerization system. The I2 doping was conducted ex-situ and using an I2 chamber method following the APP deposition. The pure and I2-doped PANI films were structurally analyzed using field emission scanning electron microscope (FE-SEM), atomic force microscope (AFM), X-ray Diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and time of flight secondary ion mass spectrometry (ToF-SIMS) studies. When increasing the I2 doping time, the plane and cross-sectional SEM images showed a decrease in the width and thickness of the PANI nanofibers, while the AFM results showed an increase in the roughness and grain size of the PANI films. Moreover, the FT-IR, XPS, and ToF-SIMS results showed an increase in the content of oxygen-containing functional groups and C=C double bonds, yet decrease in the C-N and C-H bonds when increasing the I2 doping time due to the reduction of hydrogen in the PANI films via the I2. To check the suitability of the conductive layer for polymer display applications, the resistance variations of the PANI films grown on the interdigitated electrode substrates were also examined according to the I2 doping time. [ABSTRACT FROM AUTHOR]

We report dielectric barrier discharge (DBD)-based atmospheric pressure (AP) plasma polymerization (PP) experiments using argon carrier gas and a wide variety of hydrocarbon molecules as the precursors ('monomers'). As in our preceding research with other reagents, unprecedented precision and reproducibility in energy measurements is again demonstrated. Measurements based on various aliphatic and aromatic hydrocarbon compounds have yielded values of Em, the energy absorbed from the plasma by each monomer molecule. Systematic differences among families of compounds enabled us to draw several important conclusions about fragmentation and polymerization in the DBD plasma environment, observations which are in fair qualitative agreement with low-pressure radio-frequency PP data by Yasuda and Hirotsu from the 1970s. [ABSTRACT FROM AUTHOR]

Although plasma polymerization is traditionally considered as a substrate-independent process, we present evidence that the propensity of a substrate to form carbide bonds regulates the growth mechanisms of plasma polymer (PP) films. The manner by which the first layers of PP films grow determines the adhesion and robustness of the film. Zirconium, titanium, and silicon substrates were used to study the early stages of PP film formation from a mixture of acetylene, nitrogen, and argon precursor gases. The correlation of initial growth mechanisms with the robustness of the films was evaluated through incubation of coated substrates in simulated body fluid (SBF) at 37° for 2 months. It was demonstrated that the excellent zirconium/titanium-PP film adhesion is linked to the formation of metallic carbide and oxycarbide bonds during the initial stages of film formation, where a 2D-like, layer-by-layer (Frank-van der Merwe) manner of growth was observed. On the contrary, the lower propensity of the silicon surface to form carbides leads to a 3D, island-like (Volmer-Weber) growth mode that creates a sponge-like interphase near the substrate, resulting in inferior adhesion and poor film stability in SBF. Our findings shed light on the growth mechanisms of the first layers of PP films and challenge the property of substrate independence typically attributed to plasma polymerized coatings. [ABSTRACT FROM AUTHOR]

The simple production of a new type of anti -bacterial polymer coating with embedded silver nano particles is described. This biologically active polymer layer was deposited using the plasma polymerization of allyl alcohol. Then, these plasma polymer layers were impregnated with silver ions by dipping into a solution of silver nitrate. Subsequently, Ag + was reduced by the polymer itself and more completely by dipping into a solution of sodium boron hydride. Addition of O 2 gas to the allyl alcohol monomer was used to increase the concentration of O functional groups in the layer and to improve the fixation of homogeneously distributed silver nano-particles. The thus produced films have been reduced growth of gram-negative Escherichia coli by > 99%. The morphology of prepared films was studied by Scanning Electron Microscopy and Atomic Force Microscopy. Chemical compositions in the whole layer and on the surface of films were investigated using Fourier transform infrared and X-ray photoelectron spectroscopy, respectively. [ABSTRACT FROM AUTHOR]

Thiol (SH)-terminated surfaces have been progressively gaining interest over the past years as a consequence of their widespread potential applications. Here, SH-terminated thin films have been prepared by 'co-polymerizing' gas mixtures comprising ethylene (C2H4) or butadiene (C4H6) with hydrogen sulfide (H2S). This has been accomplished by either vacuum-ultraviolet (VUV) irradiation of the flowing gas mixtures with near-monochromatic radiation from a Kr lamp, or by low-pressure r.f. plasma-enhanced chemical vapor deposition (PECVD). Varying the gas mixture ratio, R, allows one to control the films' sulfur content as well as the thiol concentration [SH]. The deposits were characterized by X-ray photoelectron spectroscopy (XPS), before and after chemical derivatization with N-ethylmaleimide, and by ATR FTIR. VUV- and plasma-prepared coatings were found to possess very similar structures and characteristics, showing chemically bonded sulfur concentrations, [S], up to 48 at% and [SH] up to 3%. All coatings remained essentially unchanged in thickness after immersion in water for 24 h. [ABSTRACT FROM AUTHOR]

This work reports about the significant impact of the substrate temperature ( TS) on the chemical composition, bond structure, and refractive index of propanethiol plasma polymers. The experiments are conducted for a TS range (30-120 ºC) related to the inherent heating observed during plasma polymerization processes. This highlights the importance of defining TS in order to reach a real control over the deposition process. Stabilizing TS is essential to establish a good correlation between the plasma chemistry and the chemical composition of the films. This allows the identification of some of the plasma species responsible for the high sulfur content reached under certain growth conditions ( S > 40%). This knowledge provides an ample control over the refractive index which is tuned within a wide range (1.63-1.82). [ABSTRACT FROM AUTHOR]

In order to confer adhesive properties to commercial polypropylene (PP) meshes, a surface plasma-induced deposition of poly-(acrylic acid) (PPAA) is performed. Once biomaterials were functionalized, different post-deposition treatments (i.e. water washing and/or thermal treatments) were investigated with the aim of monitoring the coating degradation (and therefore the loss of adhesion) after 3 months of aging in both humid/oxidant (air) and inert (nitrogen) atmospheres. A wide physicochemical characterization was carried out in order to evaluate the functionalization effectiveness and the adhesive coating homogeneity by means of static water drop shape analysis and several spectroscopies (namely, FTIR, UV–Visible and X-ray Photoemission Spectroscopy). The modification of the adhesion properties after post-deposition treatments as well as aging under different storage atmospheres were investigated by means of Atomic Force Microscopy (AFM) used in Force/Distance (F/D) mode. This technique confirms itself as a powerful tool for unveiling the surface adhesion capacity as well as the homogeneity of the functional coatings along the fibers. Results obtained evidenced that post-deposition treatments are mandatory in order to remove all oligomers produced during the plasma-treatment, whereas aging tests evidenced that these devices can be simply stored in presence of air for at least three months without a meaningful degradation of the original properties. [ABSTRACT FROM AUTHOR]