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Hexamethyldisiloxane (HMDSO) is an organosilicon compound with a modifiable bandgap, depending on the deposition conditions. This material has many unique properties due to its stability, low toxicity, and strong adhesion, making it useful as a protective barrier against corrosion, moisture, and oxidation. In this work, HMDSO films were deposited on glass substrates by the Plasma Enhanced Chemical Vapor Deposition (PECVD) technique at different deposition times. The optical properties of HMDSO films, such as dielectric permittivity, refractive index, extinction and absorption coefficients, and band gap energy, are inferred from transmission and reflection spectra. As the deposition time increased, the real part of the dielectric constant, the refractive index, and the bandgap energy showed a decrease, dropping from 4.24 to 3.40, from 2.06 to 1.84, and from 2.85 eV to 2.03 eV, respectively. The latter result is determined using classical models such as the O'Leary-Johnson-Lim ('OJL') interband transition and the harmonic oscillator model. HMDSO and Silver are used in this study for the fabrication of optical filters using two types of structures, a multiple cavity metal–dielectric (MCMD) and the Fabry–Perot structure. The silver layers are deposited by a sputtering process. The MCMD optical filter shows a higher transmittance of about 30%, but a wide range of wavelengths is transmitted. In contrast, the Fabry–Perot filter showed high contrast but a lower transmittance of about 20%. [ABSTRACT FROM AUTHOR]

Hexamethyldisiloxane (HMDSO) is an organosilicon compound with a modifiable bandgap, depending on the deposition conditions. This material has many unique properties due to its stability, low toxicity, and strong adhesion, making it useful as a protective barrier against corrosion, moisture, and oxidation. In this work, HMDSO films were deposited on glass substrates by the Plasma Enhanced Chemical Vapor Deposition (PECVD) technique at different deposition times. The optical properties of HMDSO films, such as dielectric permittivity, refractive index, extinction and absorption coefficients, and band gap energy, are inferred from transmission and reflection spectra. As the deposition time increased, the real part of the dielectric constant, the refractive index, and the bandgap energy showed a decrease, dropping from 4.24 to 3.40, from 2.06 to 1.84, and from 2.85 eV to 2.03 eV, respectively. The latter result is determined using classical models such as the O’Leary-Johnson-Lim (‘OJL’) interband transition and the harmonic oscillator model. HMDSO and Silver are used in this study for the fabrication of optical filters using two types of structures, a multiple cavity metal–dielectric (MCMD) and the Fabry–Perot structure. The silver layers are deposited by a sputtering process. The MCMD optical filter shows a higher transmittance of about 30%, but a wide range of wavelengths is transmitted. In contrast, the Fabry–Perot filter showed high contrast but a lower transmittance of about 20%.

We report on a methodology for measuring the energy dissipated per AC high voltage cycle in a cold atmospheric pressure plasma jet (CAPJet). This method is adapted from research by Nisol et al. on plasma polymerization of hexamethyldisiloxane (HMDSO) organosilicon vapor in a large area planar dielectric barrier discharge (DBD) reactor. Here too, we measured ΔEg, the energy difference with and without small HMDSO vapor concentrations in the argon carrier gas flow. From ΔEg we then derived Em, the energy per molecule, and compared values with those of Nisol. Good agreements were found, including in film structures determined from attenuated total reflectance (ATR) Fourier transform infrared (FTIR) spectra, thus suggesting that realistic Em values can be successfully obtained also for the CAPJet case. [ABSTRACT FROM AUTHOR]

The plasma polymerization of hexamethyldisiloxane (HMDSO) leads to the environmentally friendly fabrication of water-repellent coatings through a vapor-phase surface functionalization process using alternatives to the controversial perfluoroacrylate precursors. However, the durability of these coatings is their Achilles' heel, which requires an in-depth study of the relationship between the structure and properties of these thin films in order to propose concrete solutions for the fabrication of fluorine-free water-repellent textiles. In this context, HMDSO plasma polymers have been deposited on cotton fabrics in an original reactor that allows easy tuning of temporal and spatial parameters of the glow discharge. The functionalized fabrics were characterized to gain insights into the chemical composition of the coatings, their morphology and, above all, their adhesion properties. Interestingly, the results after washing tests revealed a significant dependence of the durability of the superhydrophobic property on the elastic modulus of the deposited polymer. The formation of some radicals at the substrate–thin film interface in the early stages of deposition also correlates with some results. These relationships between the operating conditions of the plasma polymerization, the interfacial properties and the performances of the functionalized fabrics, but also the characterization methodology developed in this work, can undoubtedly serve the engineering of water-repellent fluorine-free coatings on fabrics with optimal durability. [ABSTRACT FROM AUTHOR]

Titanium dioxide has attracted a great deal of attention in the field of environmental purification due to its photocatalytic activity under ultraviolet light. Photocatalytic efficiency and the energy required to initiate the process remain the drawbacks that hinder the widespread adoption of the process. Consistently with this, it is proposed here the polymerization of hexamethyldisiloxane fragments simultaneously to TiO2 sputtering for the production of thin films in low-pressure plasma. The effect of plasma excitation power on the molecular structure and chemical composition of the films was evaluated by infrared spectroscopy. Wettability and surface energy were assessed by a sessile drop technique, using deionized water and diiodomethane. The morphology and elemental composition of the films were determined using scanning electron microscopy and energy dispersive spectroscopy, respectively. The thickness and roughness of the resulting films were measured using profilometry. Organosilicon-to-silica films, with different properties, were deposited by combining both deposition processes. Titanium was detected from the structures fabricated by the hybrid method. It has been observed that the proportion of titanium and particles incorporated into silicon-based matrices depends on the plasma excitation power. In general, a decrease in film thickness with increasing power has been observed. The presence of Ti in the plasma atmosphere alters the plasma deposition mechanism, affecting film deposition rate, roughness, and wettability. An interpretation of the excitation power dependence on the plasma activation level and sputtering yield is proposed. The methodology developed here will encourage researchers to create TiO2 films on a range of substrates for their prospective use as sensor electrodes, water and air purification systems, and biocompatible materials. [ABSTRACT FROM AUTHOR]

Hydrogen sensors are easily deactivated by hexamethyldisiloxane (HMDSO) poisoning. Moreover, the existing anti-poisoning strategies can also damage the overall sensing performance of these hydrogen sensors. Therefore, a new bilayer design with a Pd/In 2 O 3 sensitive layer and an In 2 O 3 /Al 2 O 3 catalytic filter layer is proposed to avoid the deactivation of hydrogen sensors. The In 2 O 3 /Al 2 O 3 layer helps in hindering HMDSO and its decomposition products from reaching the Pd/In 2 O 3 layer. The H 2 response of the sensors is enhanced due to the small size of In 2 O 3 and the electronic sensitization of Pd. As a result, the bilayer sensors exhibit high response (Ra/Rg = 53) and ultra-fast response time (1 s) towards 3000 ppm H 2 at 365 °C. The resistance and the H 2 response of the bilayer sensors are almost unchanged after 40 min of 10 ppm HDMSO poisoning. In this paper, the mechanism of resistance against silicone poisoning and the H 2 response of the bilayer sensors are discussed from the separation of sensing and catalytic filtration reactions to the behavior of adsorbed oxygen. [Display omitted] • Unique two-layer sensor design with catalytic filter layer and sensitive layer. • Bilayer sensors exhibit very short response/recovery times while resisting HMDSO. • After poisoning, the resistance and response of the sensor remain stable. • The sensing mechanism of the double-layer sensor is discussed. [ABSTRACT FROM AUTHOR]

Plasma co-polymers (co-p) were deposited with an atmospheric pressure plasma jet (APPJ) using a precursor mixture containing hexamethyldisiloxane (HMDSO) and limonene. A coating with fragments from both precursors and with siloxane, carbonyl and nitrogen functional groups was deposited. The flow rate of limonene was found to be an important parameter for plasma co-polymerization to tune the formation and structure of the functional groups. The FTIR and XPS analysis indicates that with increasing flow rate of limonene a higher proportion of carbon is bound to silicon. This is related to a stronger incorporation of fragments from limonene into the siloxane network and a weaker fragmentation of HMDSO. The formation mechanism of the nitroxide and carboxyl groups can be mainly differentiated into in-plasma and post-plasma reactions, respectively.

جرى توضيع أغشية رقيقة من سداسي ميثيل السيلوكسان المتبلمرة بلازمياً (pp-HMDSO) باستخدام تقنية توضيع البخار الكيميائي المعزز بالبلازما (PECVD)، وجرى دراسة تأثير هذه الأغشية من ناحية تحسين حماية السطوح الموضَّع عليها (وهي الفولاذ المقاوم للصدأ SS316L) من التآكل، وذلك في وسط مخرِّش من محلول 0.9% NaCl، وقياس القساوة الميكروية، حيث رُسّبت الأغشية الرقيقة من HMDSO على ركائز من الفولاذ المقاوم للصدأ SS316L وعلى ركائز من السليكون بهدف تحليل مورفولوجية هذه الأغشية بمجهر القوة الذرية (AFM) Atomic Force Microscope، اضافةً الى توضيع هذه الأغشية على مجاوب بلورة من مادة الكوارتزQuartz Crystal Microbalance (QCM)، وذلك ضمن الشروط المحددة نفسها بهدف قياس ثخانتها، كما أجريت الاختبارات الكهروكيميائية باستخدام تقنية الاستقطاب تافل لدراسة مقاومتها للتآكل الكهروكيميائي، وتم كذلك إجراء اختبار القساوة الميكروية على هذه الركائز والعينات المرجعية. وبعد غمر الركائز(الموضع عليها الأغشية الرقيسقة المونه عنها أنفاً) لمدة عشرة أيام في الوسط المخرش، أظهرت النتائج خواصاً واعدة للحماية من التآكل لهذه الأغشية الرقيقة pp-HMDSO (موضوع البحث).

Titanium dioxide has attracted a great deal of attention in the field of environmental purification due to its photocatalytic activity under ultraviolet light. Photocatalytic efficiency and the energy required to initiate the process remain the drawbacks that hinder the widespread adoption of the process. Consistently with this, it is proposed here the polymerization of hexamethyldisiloxane fragments simultaneously to TiO2 sputtering for the production of thin films in low-pressure plasma. The effect of plasma excitation power on the molecular structure and chemical composition of the films was evaluated by infrared spectroscopy. Wettability and surface energy were assessed by a sessile drop technique, using deionized water and diiodomethane. The morphology and elemental composition of the films were determined using scanning electron microscopy and energy dispersive spectroscopy, respectively. The thickness and roughness of the resulting films were measured using profilometry. Organosilicon-to-silica films, with different properties, were deposited by combining both deposition processes. Titanium was detected from the structures fabricated by the hybrid method. It has been observed that the proportion of titanium and particles incorporated into silicon-based matrices depends on the plasma excitation power. In general, a decrease in film thickness with increasing power has been observed. The presence of Ti in the plasma atmosphere alters the plasma deposition mechanism, affecting film deposition rate, roughness, and wettability. An interpretation of the excitation power dependence on the plasma activation level and sputtering yield is proposed. The methodology developed here will encourage researchers to create TiO2 films on a range of substrates for their prospective use as sensor electrodes, water and air purification systems, and biocompatible materials.

A series of 3 C-SiC coatings were prepared by organometallic chemical vapor deposition (MOCVD) using precursor solution containing a varying proportion of commercial-grade hexamethyldisiloxane (HMDSO) and n-hexane. The phase composition, bonding state, and microstructure of 3 C-SiC coatings were studied in detail by grazing incidence X-ray diffraction (GIXRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). The microstructure and mechanical properties of the optimal 3 C-SiC coating were characterized by scanning transmission electron microscopy (STEM) and nanoindentation, respectively. Our results revealed that the amount of undesired graphite phase can be significantly reduced in the 3 C-SiC coating by introducing hydrogen gas in the reaction chamber alongside increasing the ratio of HMDSO/n-hexane in the precursor mixture. The STEM results revealed that the optimal coating was predominantly composed of nano-crystalline 3 C-SiC grains alongside a small amount of amorphous graphite. The hardness and elastic modulus of the optimal coating were 38.19 GPa and 363.2 GPa, respectively. [ABSTRACT FROM AUTHOR]

Organosilicon films were deposited on SAE 1020 steel by an atmospheric pressure plasma jet system using hexamethyldisiloxane (HMDSO) monomer as a polymerizing agent. Several experimental parameters, such as deposition mode (continuous or alternated), deposition time, and number of deposition steps, were varied to obtain stable coatings with improved corrosion resistance. To evaluate the surface characteristics of the obtained films, the following analyses were performed: water contact angle (WCA) measurements, scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). Additionally, some electrochemical analyses like open circuit potential (OCP), electrochemical impedance spectroscopy (EIS), and linear potentiodynamic polarization measurements were carried out to evaluate the corrosion resistance and the stability of the obtained films. From these results, it can be concluded that the corrosion resistance of the coated samples increased significantly when compared to the pristine SAE 1020 steel. Moreover, the three-step deposition process was more efficient in promoting corrosion resistance than the continuous film deposition. [ABSTRACT FROM AUTHOR]

The high corrosivity of MgLi alloy limits its wide application in maritime, aerospace, electronic device, etc. Therefore, there is an urgent need for an efficient coating to effectively protect it. In this study, hexamethyldisiloxane (HMDSO) was utilized as a precursor to deposit polysiloxane films on MgLi alloy using Plasma Enhanced Chemical Vapor Deposition (PECVD) technology, aimed at improving surface properties and enhancing corrosion resistance. By adjusting the O 2 flow rate, a series of films with different properties were prepared, and their structures were transitioned from organic (SiO x C y H z) to inorganic (SiO x). The test results showed that different O 2 flow rates led to different deposition rates, the film thickness initially increased and then decreased. With the increase in O 2 flow rate, the content of O element in the film gradually increases, the molecular chain extension of the film increases the crosslinking degree, which changes the mechanical properties and wettability. Electrochemical tests showed that the corrosion current density of the coated MgLi alloy is decreased by 5 orders of magnitude compared to the bare MgLi alloy. Additionally, in the voltage corrosion test at 10 V, the film showed good endurance against current breakdown, and the film surface was not damaged after 2 min of test. • Polysiloxane films were prepared on the Mg Li alloy surface by PECVD technique. • Various properties of the films prepared at different O 2 flow rates were analyzed. • Electrochemical tests show that the film greatly enhances the corrosion resistance of the Mg Li alloy. • Constant voltage corrosion tests show that the film has excellent barrier properties. [ABSTRACT FROM AUTHOR]

Abstract Recently, there has been growing interest in the incorporation of particles in plasma deposited thin films to creation of multifunctional surfaces. In this work a new hybrid methodology based on the plasma enhanced chemical vapor deposition (PECVD) of hexamethyldisiloxane combined to the reactive sputtering of TiO2 is proposed for the preparation of SiOxCyHz-TiO2 composite films. Specifically, the effect of the proportion of O2 in the plasma environment on the morphology, chemical structure, elemental composition, wettability, thickness and surface roughness, of the films was studied. Agglomerates of TiO2 (16-83 μm) were detected into the organosilicon matrix with the concentration of particulates growing with the percentage of oxygen in the feed. In general, there was elevation in the angle of contact of the surfaces as the oxygen supply increased. Interpretation is proposed in terms of the influence of the oxygen supply on the TiO2 sputtering rate and in the oxidation of plasma species.

Current parenteral containers used for the storage and delivery of protein-based drugs, contain silicone oil which may seep into the protein solution and can result in adsorption, aggregation and denaturation of the protein. Tightly adherent surface coatings prepared by radio frequency glow-discharge (RFGD) plasma polymerization are described in this paper. Using this robust technique, methacrylic acid (MA) (hydrophilic), hexamethyldisiloxane (HMDSO) (hydrophobic), tetraglyme (TG) (hydrophilic) were plasma polymerized onto glass. In addition, HMDSO and MA were copolymerized to create a plasma polymerized HMDSO-MA (hydrophobic) surface. Untreated glass and glass dip-coated in PDMS were used as controls. TG and MA plasma coatings adsorbed the least amount of protein in all pH conditions. Interestingly HMDSO-MA retained significantly lesser protein compared to HMDSO and dip-coated PDMS samples. In the presence of Polysorbate 80 (PS80) all plasma polymerized coatings adsorbed and retained negligible amounts of protein, compared to controls. Furthermore, the peak glide force of plasma coated syringes did not significantly increase compared to syringes without plasma coating. Due to the versatility of RFGD plasma, this process is scalable and could potentially be used for the treatment of hypodermic syringes used for the storage and delivery of protein-based therapeutics. [ABSTRACT FROM AUTHOR]

Using SEM and EDX, we observed the conversion of the HMDS molecule to the HMDSO molecule as a result of contact with moisture or water. We prepared the samples by incubating them for 8 to 24 h at room temperature in moisture and moisture-free environments. After gradual imaging of the samples, the formation stages of the HMDSO molecule were observed. [ABSTRACT FROM AUTHOR]

In this work, we present the performance improved InGaZnO thin film transistors by inserting low temperature processed 10 nm thick SiOCH buffer layers between SiN x insulator and InGaZnO channel layer. The influences of oxygen flow rate during the deposition of SiOCH buffer layer have been intensively investigated. Basing on the analysis of hall effect measurement and Fourier transform infrared spectrum, the SiOCH buffer layer can effectively increase the carrier concentration of the channel layer by the hydrogen doping due to re-sputtering and diffusion effect. The InGaZnO thin film transistor with buffer layer exhibits an enhanced performance with mobility of 13.09 cm2/vs, threshold voltage of −0.55 V and I on /I off over 106. In this work, we present the performance improved InGaZnO based thin film transistors by inserting low temperature processed 10 nm thick SiOCH buffer layers between SiN x insulator and InGaZnO channel layer. The influences of oxygen flow rate during the deposition of SiOCH buffer layer have been intensively investigated. Basing on the analysis of hall effect measurement and Fourier transform infrared spectrum, the SiOCH buffer layer can effectively increase the carrier concentration of the channel layer by the hydrogen doping due to re-sputtering and diffusion effect. Image 1 • The SiOCH buffer layer was inserted between insulator and channel layer to modify the performance of InGaZnO TFT. • The influence of oxygen flow rate during the deposition of buffer layer on InGaZnO TFT has been investigated in detail. • The SiOCH buffer layer could increase the carrier concentration of adjacent InGaZnO layer by hydrogen doping effect. [ABSTRACT FROM AUTHOR]

Plasma enhanced chemical vapor deposition is a promising process for the generation of tailor-made polymer coatings on medical devices in order to improve their implant/ host interaction. The ultra-thin coatings can fulfil a variety of purposes, depending on the monomers used, the process conditions and the location of the coated implants in the human body. In addition, even complex geometries can be coated easily and without the application of solvents. Particularly hydrophilic and hydrophobic plasma polymer coatings can improve biocompatibility, especially in blood contact. Furthermore, the selection of the monomers used enables the generation of specific functional groups for further surface immobilization of drugs, such as proteins, by chemical crosslinking. The release of toxic residues from polymeric implants, such as monomers, additives or degraded components, can also be avoided. The aim of our investigation was the generation of plasma polymer films, their characterization and application as coatings for biodegradable metallic biomaterials in order to retard the degradation process. Metallic biomaterials, in various forms are frequently used in orthopaedics, dentistry, cardiovascular and neurosurgical equipment, because of their tensile strength, fracture toughness, fatigue strength and electrical conductivity. Plasma polymerization was performed using the monomers hexamethyldisiloxane and allylamine. The resulting plasma polymers were analysed in an accelerated degradation test. Both plasma polymers appear to be promising, while polyHMDSO appears to degrade over time and polyallylamine indicates to be stable.

Electrically conductive nonwoven polyester fabric MILIFE® with a chemically deposited copper layer was coated by the PECVD method using the mixture of HMDSO (hexamethyldisiloxane) as organosilicate precursor and oxygen. The metallized fabric with and without silica coating was subsequently tested under strongly corrosive conditions of acid and oxidizing environment. The degree of corrosion damage of the electrically conductive copper layer was determined by changes in electrical resistance measured on its surface. We have proven that silicon-based thin layer can protect the conductive metallic layers from corrosive environmental influences. The plasma-polymerized coating of silicon-based nanolayer significantly prolongs the life of metallized polyester nonwoven and extends its use to areas of long4erm corrosive conditions. [ABSTRACT FROM AUTHOR]

This study investigates the feasibility of plasma‐supported in‐line functionalization of silicon nanoparticles (NPs) in an atmospheric pressure gas‐phase reactor. The approach utilizes the synthesis of core silicon NPs and their subsequent coating downstream of the particle formation zone. In‐line coating is accomplished with a cylindrical coating nozzle to achieve homogenous mixing of coating precursor vapors with in‐coming NPs. Multiple siloxanes were tested for their coating suitability and their ability towards coating homogeneity. It was found that tetraethyl orthosilicate is favored for thin layers consisting of almost pure silica while hexamethyldisiloxane and octamethylcyclotetrasiloxane (OMCTS) coatings contained reasonable amounts of hydrocarbons. Moreover, OMCTS showed a pronounced tendency towards homogeneous nucleation, thus leading to the additional formation of silica NPs due to homogeneous nucleation. [ABSTRACT FROM AUTHOR]

In this study, hexamethyldisiloxane was polymerized on the biaxially oriented polypropylene films by low-pressure radio frequency (RF) plasma. The samples were polymerized by using RF plasma in the frequency range of 13.56 MHz at the different polymerization times. The surface properties and chemical structure of samples were examined by contact angle measurement, atomic force microscopy, scanning electron microscopy and Fourier transformation infrared (FTIR). Also, the scratch behavior and the mechanical properties of samples were evaluated by using SPM lithography. In this work, some distinguishing changes were observed in properties of polymerized samples in comparison with raw sample. Results showed that the scratch resistance increased by prolonging polymerization time, whereas the surface energy decreased dramatically. It can be inferred from SPM and FTIR data that there is a direct relationship between scratch resistance and chemical composition of samples. Scratch resistance is mostly affected by silicon compounds deposited on the samples. Plasma polymerization causes changes in the chemical structure and surface properties of samples. [ABSTRACT FROM AUTHOR]

[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]

To overcome challenges for manufacturing of modern smart medical plastic parts by injection molding, e.g. for active implants, the optimization of the interface between electronics and the polymer component concerning adhesion and diffusion behavior is crucial. Our results indicate that a nano-sized SiOxCyHz layer formed by plasma-enhanced chemical vapour deposition (PE-CVD) via open air atmospheric pressure plasma jet (APPJ) and by use of a hexamthyldisiloxane (HMDSO) precursor can form a non-corrosive, anti-permeable and biocompatible coating. Due to the open air character of the APPJ process an inline coating before overmolding could be an easy applicable method and a promising advancement.

This work aims at studying the impact of silane-based coatings, generated by atmospheric pressure plasma spraying (APPS) of a liquid precursor (hexamethydisiloxane – HMDSO), on dairy antifouling and antibacterial properties of food-grade 316L stainless steel. The influence of the manufacturing parameters (precursor flow rate, nozzle-to-substrate distance and scanning speed) on the coatings properties was investigated using a wide range of characterization techniques (drop shape analysis, X-Ray Mappings, Scanning Electron Microscopy, Fourier-Transformed Infrared Spectroscopy, Atomic Force Microscopy). Coating’s roughness in particular was shown to strongly increase when precursor flow rate increases. A pilot pasteurizer, fed with a model foulant solution (whey protein and calcium), allowed performing two consecutive industrial-like isothermal dairy fouling tests, revealing the promising anti-fouling properties of the HMDSO-coated steel. A fouling reduction of up to 90% compared to bare stainless steel was achieved after first cycle for all samples. The second fouling run allowed to select the best-performing sample, which kept the same antifouling properties as in the first test. Its mechanism of action was investigated, which revealed that a nanostructured, Si-O-Si rich surface was efficient to prevent isothermal dairy fouling. The adhesion of the pathogenic bacterium Staphylococcus aureus also proved to be impacted by this plasma coating, with a significant decrease of adhered cells (−30% compared to native stainless steel). [ABSTRACT FROM AUTHOR]

The aim of this study was to develop and characterize wettability, morphology, chemical composition and color of plasma-deposited thin films on the surface of dental materials. A porcelain (VM9, VITA (PC)) and two indirect composite discs (Enamic, VITA (EN) and Lava Ultimate, 3M ESPE (LU)) were used. Different methodologies of film deposition were established: plasma-enhanced chemical vapor deposition (PECVD) with HMDSO/Ar (PAr); PECVD with HMDSO/O 2 (PO 2 ); plasma immersion ion implantation and deposition using HMDSO/Ar (PII). Surface roughness and film thickness were determined by profilometry. Contact angles were measured with a goniometer. Morphological analysis was evaluated using SEM and chemical composition was investigated by FTIR and XPS. Color differences (ΔE) were verified by a spectrophotometer. The films' thicknesses were 620 nm (PAr), 540 nm (PO 2 ) and 70 nm (PII). Surface roughness was not changed for most of the groups. An increase in contact angles for all film groups was detected, except for LU-PII group. In PO 2 films, granular structures covered the entire surface and their presence decreased in PAr and PII. Color differences maintained below 3.0. PO 2 showed a silica-like and PII silicon oxycarbide-like structure and PAr presented an organic behavior. Plasma-deposited thin films were developed and altered surface characteristics of restorative materials, maintaining the materials color and adequate surface roughness potentially working as a protective barrier. [ABSTRACT FROM AUTHOR]

Residual stress measurements of thin films are common practice in device technology and are extremely important in particular for the characterization of thin film coatings. A largely ignored stress contribution is the difference in coefficient of hygroscopic expansion between the coating and substrate. This paper presents a rather novel approach to accurately evaluate the residual stress and coefficient of hygroscopic expansion of strongly curved specimens. Silicon-containing plasma polymer coatings with different carbon contents were deposited using hollow cathode arc discharge based PECVD. Samples of different layer composition were produced comprising silicon-containing plasma-polymer layers with a high carbon concentration and more “inorganic” SiO 2 like layers with lower carbon concentration. All coatings show a compressive stress state. The highest stress was measured in the coating with the highest carbon content (239 ± 6 MPa) and decreases to 94 ± 31 MPa at lower carbon contents. Variation of the humidity showed that all coatings expand under influence of increasing relative humidity. The most inorganic coatings exhibits the highest expansion coefficient of 29.2 ± 2·10 −6 (% r.h.) −1 . The results obtained were compared with the results from contact angle measurements. An increase in the hygroscopic expansion corresponds with an increasing hydrophilicity of the coatings. [ABSTRACT FROM AUTHOR]

Recently, plasma deposition at atmospheric pressure has become a promising technology due to its reduced equipment costs and its possibility of in‐line processing. The main aim of this work was to show a process for the deposition of functional layers on hollow objects surface by plasma discharge generated above the liquid electrolyte. In principle, this process is based on the surface dielectric barrier discharge, where the plasma is generated from the boundary line of liquid precursor and dielectric surface. As a model precursor compound a hexamethyldisiloxane was chosen for deposition on external and internal wall surface of polytetrafluoroethylene tube. [ABSTRACT FROM AUTHOR]

A dielectric barrier discharge containing argon and oxygen is used to dissociate HMDSO with the purpose of producing silica-like particles. Solid material is deposited in an electrostatic precipitator and analyzed with SEM, FTIR, and weight measurements. The variation of oxygen concentration shows an optimum for particle yield at an oxygen-to-monomer ratio of 20. Increasing yield and nanoparticle formation are also found with increasing excitation frequency and explained with the corresponding higher power input and nanoparticle survival rates from aerosol theory. Nanoparticles only form when residence time allows decomposition, nucleation, and growth. [ABSTRACT FROM AUTHOR]

In this work, the deposition of SiOx films from O2/hexamethyldisiloxan (HMDSO) or Ar/HMDSO mixtures in an inductively coupled plasma is investigated. Substrate temperature and electron density are measured during the deposition process. Furthermore, the deposited layers are analyzed with a profilometer (thickness), infrared absorption spectroscopy (FTIR), and X‐ray photoelectron spectroscopy (XPS). Processes with continuous and pulsed HMDSO flows are compared to characterize the effect of surface treatment of a grown layer. Pure O2 or Ar plasmas between the HMDSO gas flow pulses can offer a “post‐oxidation” or “post‐treatment” of the grown films. The discharge dynamics during the different phases are also investigated by time‐resolved electron density measurements. This approach has led to formation of carbon and Si‐OH group free SiOx films even without addition of O2 gas under atmospheric pressure conditions. [ABSTRACT FROM AUTHOR]

In this work, we study the hydrophobic properties of silk fabrics by deposition of plasma-polymerized (pp) hexamethyldisiloxane (HMDSO) using low-pressure plasma-enhanced chemical vapor deposition. Recently, hydrophobic properties are under active research in textile industry. The effects of coating time and power on the HMDSO-coated silk fabrics are investigated. Water contact angle of pp-HMDSO-coated silk fabric surface is measured as a function of power and coating time. Fabric surface shows an enhancement in hydrophobicity after coating. Attenuated total reflectance-Fourier transform infrared spectroscopy reveals the surface chemistry, and scanning electron microscopy shows the surface morphology of the uncoated and HMDSO-coated fabrics, respectively. In the case of uncoated fabric, water droplet absorbs swiftly, whereas in the case of HMDSO-coated fabric, water droplet remains on the fabric surface with a maximum contact angle of 140. The HMDSO-deposited silk surface is found to be durable after detergent washing. Common stains such as ink, tea, milk, turmeric and orange juice are tested on the surface of both fabrics. In HMDSO-coated fabrics, all the stains are bedded like ball droplet. In order to study the self-cleaning property, the fabric is tilted to 45 angle; stain droplets easily roll off from the fabric. [ABSTRACT FROM AUTHOR]

This study focused on the corrosion protection performance of plasma polymerized HMDSO thin films in two different corrosive medias, 0.3M NaCl and 0.3M H2SO4. The pp-HMDSO thin films were deposited on steel substrates for electrochemical tests using the potentiodynamic polarization technique, they were deposited also on aluminum and silicon substrates to investigate their resistance to corrosion, through the analysis of the degradation of microhardness and morphology, respectively, after immersion of the substrates for one week in the corrosive media. The results showed promising corrosion protection properties of the pp-HMDSO thin films. [ABSTRACT FROM AUTHOR]

The original article contained errors in a number of symbols within the text. Extraneous characters were added before and after the symbol. The original version is now corrected and is available at https://doi.org/10.1255/jsi.2017.a3.

This study investigates the potential use of attenuated total internal reflection-Fourier transform infrared (ATR-FT-IR) imaging, a hyperspectral imaging modality, to investigate molecular level trends in the interaction of water with polymeric surfaces of varying hydrophobicity. The hydrophobicity of two categories of polymeric biomaterials is characterised using contact angle (CA) measurements and their relationship with the band area of the OH stretching vs vibration of water over time is presented. This is supported with correlations between CA data and single wavenumber intensity values (univariate analysis). Multivariate analysis of the spectra captured at the OH stretch for all polymers is carried out using principal component analysis to study the spatial variation in the interaction between the polymeric surfaces and water. Finally, a comparison between the univariate and multivariate strategies is presented to understand the interaction between polymeric biomaterials and water. This is a corrected version of the original paper; this corrected version was published on 15 May 2017. Please see Erratum at https://doi.org/10.1255/jsi.2017.a3e.

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Electrochemical migration (ECM) in silver (Ag) mesh transparent conductive films (TCFs) was evaluated by thermal humidity bias (THB) and water drop (WD) tests, showing color change and dendrites formation at the unprotected electrode gaps. Flexible barrier layer deposited by low temperature inductively coupled plasma enhanced chemical vapor deposition (IC-PECVD) process was applied to prevent Ag mesh TCFs from ECM. The barrier layer structure was organosilicon/SiOx pairs deposited with the mixture of HMDSO, O2 and Ar at different ratios in the same PECVD chamber. The study indicated that the ECM behavior of Ag mesh can be well suppressed by the barrier layer at water vapor transmission rate (WVTR) of 8.8×10-3g/m2/day. [ABSTRACT FROM AUTHOR]

An RF driven non-thermal atmospheric pressure plasma jet used for plasma enhanced chemical vapor deposition is investigated by hydrodynamic modeling. The model describes the gas flow and heating, the plasma generation in the active zone, reactions of active plasma particles with precursor molecules in the effluent, and the transport of precursor fragments toward the substrate. Molecular argon ions are found to be the dominant active species transported into the effluent together with slow electrons. The radial profiles of the fluxes of precursor fragments onto the substrate depend sensitively on the flow conditions. Satisfactory agreement of the calculated gas temperature with measured profiles is obtained. [ABSTRACT FROM AUTHOR]

Films were produced on stainless-steel substrates by radiofrequency Plasma Enhanced Chemical Vapor Deposition (RF-PECVD) of mixtures containing 70% hexamethyldisiloxane, 20% oxygen and 10% argon. While the plasma excitation power was varied from 15 to 75 W, the deposition time and total gas pressure were kept constant at 1800 s and 8.0 Pa, respectively. The influences of the plasma power on the plasma kinetics and the ion bombardment of the growing film are discussed. Film composition and chemical structure were determined using X-ray photoelectron- and infrared reflectance-absorbance spectroscopy, respectively. Profilometry was used to measure the thicknesses of the resulting layers. The root mean square roughness was evaluated from surface topographic profiles acquired by atomic force microscopy. Scanning electron microscopy and energy dispersive spectroscopy were employed to evaluate the morphology and elemental composition of the coatings. Electrochemical impedance spectroscopy and potentiodynamic polarization tests were used to derive the corrosion resistance of the samples to a saline solution. Substantial changes in the material structure and progressive increases in film thickness were observed with increasing applied power. The resulting material was an organosilicon layer composed of Si O backbones surrounded by methyl groups, very similar to conventional polydimethylsiloxane. Increases in the proportions of Si O and methylsilyl groups in the structure were observed at greater plasma excitation powers, indicating densification of the structure owing to greater ion bombardment. The surface morphology and roughness were also dependent on the treatment power. Independently of the deposition conditions, application of the film increased the corrosion resistance of the stainless steel. A 10,000-fold elevation in the total system resistance under electrochemical testing was achieved for the film prepared with the greatest ion bombardment intensity. Film thickness was observed to be a key parameter but the coating structure had a major effect on this result. [ABSTRACT FROM AUTHOR]

Silicon dioxide nanoparticles are generated in a lean hydrogen/oxygen flat flame doped with small amounts of hexamethyldisiloxane (HMDSO) stabilized by a water-cooled sintered bronze matrix. The burner is housed in an optically-accessible low-pressure (3 kPa) chamber. Temperature fields were determined via multi-line laser-induced fluorescence (LIF) using added NO as target species. Gas-phase silicon oxide (SiO) was detected via laser-induced fluorescence (LIF) by exciting the weakly temperature-dependent rovibrational Q 11 (32) transition in the A–X (0,0) vibronic band system at 235.087 nm. Semi-quantitative concentration profiles as a function of height-above-burner (HAB) were obtained after exploiting the measured temperature fields and correcting measured LIF intensities for the temperature-dependence of the ground-state population and collisional quenching using measured effective fluorescence lifetimes. Particle sizes were determined as a function of HAB via molecular-beam sampling with subsequent particle mass spectrometry (PMS). The experimental data were used to develop a simple kinetics model of HMDSO combustion and SiO 2 particle precursor formation with subsequent nucleation and particle growth in the H 2 /O 2 flame. The model was incorporated in a CFD simulation to account for facility effects that arise from modified flow fields and heat transfer between the flame and the reactor chamber. [ABSTRACT FROM AUTHOR]

The mass sensitivity of thin aluminum nitride (AlN) film S0 Lamb wave resonators is theoretically and experimentally studied. Theoretical predictions based on modal and finite elements method analysis are experimentally verified. Here, two-port 888 MHz synchronous FPARs are micromachined and subsequently coated with hexamethyl-disiloxane(HMDSO)-plasma-polymerized thin films of various thicknesses. Systematic data on frequency shift and insertion loss versus film thickness are presented. FPARs demonstrate high mass-loading sensitivity as well as good tolerance towards the HMDSO viscous losses. Initial measurements in gas phase environment are further presented.

Recently, various nanotechnologies have been utilized with regard to membrane modification due to their high activities and the low cost of the nanomaterials involved. In order to enhance the hydrophobicity of the membrane surface for membrane distillation applications by decreasing the surface energy, a radio-frequency plasma-enhanced chemical vapor deposition (RF-PECVD) process is suggested with surface nanostructuring and a subsequent hydrophobic coating step. In this research, a commercial PVDF membrane was modified by plasma treatments with the two different gases of O 2 and CF 4 . The water contact angles of the active layers increased from 73 to 117 and 101° and the fluxes of the treated membranes increased to 63 and 27.9% as compared to a virgin PVDF membrane when the feed used was D.I. water by the O 2 and CF 4 plasma modifications, respectively. Defluorination at the long exposure time (120 min) of the plasma treatment and increase of the overall hydrophobicity (the decrease of the contact angle hysteresis) by the HMDSO coating were the reasons of the flux variations for the plasma modified membranes. [ABSTRACT FROM AUTHOR]

Polyamide, PA, is a thermoplastic very used in practical applications once it associates a series of convenient properties. However, its affinity towards water promotes swelling and thus dimensional changes, a drawback for most of the applications. There exist alternative polymers but the fully bulk replacement is hindered by costs. In this sense, the modification of polymer surfaces using a versatile, simple and low cost methodology emerges as an important tool. In this work, low pressure plasmas were employed to adjust the surface properties of the commercial polyamide 6 aiming to decrease its affinity to water. Organosilicon films were deposited from hexamethyldisiloxane, HMDSO, oxygen and argon plasma mixtures. The plasma reactor was pumped down to 3.0 Pa and HMDSO, oxygen and argon were admitted to the reactor establishing the pressure of 24 Pa. In each one of the four deposition cycles, the HMDSO proportion was fixed at 70% while those of oxygen (0 to 30%) and argon (30 to 0%) were varied in opposite ways. The plasma was ignited by the application of radiofrequency power (13.56 MHz, 150 W) to the lowermost sample holder, earthening the top electrode. Deposition was conducted for 1800 s. It was specifically investigated if the receptivity of the organosilicon film to water can be further reduced by adjusting its topography. Infrared spectroscopy was used to determine the molecular structure of the samples while water wettability was measured by the contact angle approach. Surface microstructure was inspected by scanning electron microscopy and atomic force microscopy. Elemental composition was derived from energy dispersive spectroscopy. Films are in general organosilicon with methyl functionals connected to the SiOSi backbone as lateral groups and/or chain termination in a more crosslinked way than the conventional silicone. A granular structure composed by agglomerates of different diameters was generated. Roughness is affected by the proportion of the dilution gases since it influences the deposition kinetics and then the rate of polymerization in the plasma phase. Independently of the oxygen and argon proportions used in the plasma polymerization process, the bare hydrophilic PA was converted into hydrophobic upon film deposition. [ABSTRACT FROM AUTHOR]

Many studies have shown that starch is a good alternative to produce biodegradable plastics. Corn starch based films were prepared by solvent evaporation using water and glycerol as plasticizers and their surfaces were modified by chemical vapor deposition (CVD) employing different plasma treatments in order to induce different surface wettability characteristics. Three different surfaces were produced: (i) starch modified by helium (He) plasma at −100 V for 10 min; (ii) starch coated using hexamethyldisiloxane (HMDSO) monomer at −60 V for 20 min;and (iii) starch surface modification by He plasma at −100 V for 10 min followed by coating with HMDSO monomer at −60 V for 20 min. The results indicated that He plasma treatment under this condition was not able to induce changes in the surface wettability, but HMDSO coating led to surface hydrophobization, both of the as-prepared starch films and the He-modified surfaces. [ABSTRACT FROM AUTHOR]