Organosilicon Films Research Articles

Simulation study of organosilicon coating of a spherical nanoparticle immersed in a low-pressure HMDSO/O2 plasma

Using numerical simulations of the multi-fluid equations along with a surface model, the deposition of thin organosilicon films on a spherical nanoparticle immersed in a low-pressure HMDSO/O2 plasma is studied. The effects of variation in the O2 fraction, electron temperature, gas pressure, and the processing temperature on the incident fluxes of the film precursors, the deposition rate, and film thickness, as well as on the relative concentrations of the silicon, oxygen, and carbon in the film structure are investigated. The results revealed that the deposition dynamics is dominated by the SiOC3H9 radical, produced mainly by the electron impact dissociation of the HMDSO molecules. is the most populated ion and plays a prominent role in the deposition process via both direct incorporation and ion-induced stitching. The deposition rate and consequently the film thickness are enhanced with an increase in the electron temperature and the total gas pressure but are reduced with an increase in O2 fraction and the gas temperature. The increase in O2/HMDSO ratio and also the elevation of the electron and gas temperatures lead to an enhanced oxygen/carbon ratio in the film structure, an indication of a high degree of cross-linking. As the pressure rises, the oxygen content of the film increases initially while the carbon content declines, but the reverse is true at higher pressures, due to less effective fragmentation.

Comparative investigation on organosilicon film growth by cyclonic plasma using hexamethyldisilazane and hexamethyldisilazane/nitrogen gas mixture

This study aimed to discover the surface characteristics of cyclonic plasma‐deposited films and the effect of nitrogen gas addition. The influence of nitrogen gas addition on the surface characteristics of organosilicon films in hexamethyldisilazane (HMDSN) and HMDSN/nitrogen (HMDSN/N2) cyclonic plasmas at atmospheric pressure was evaluated. It was found that the addition of nitrogen gas is a crucial factor affecting organosilicon film growth in the plasma cyclone in one atmosphere. SEM, AFM, and ATR‐FTIR results indicated that on adding nitrogen gas, the surface morphology became rougher, the peak corresponding to the Si–O–Si group was detected at approximately 1050 cm−1, the degree of porosity was relatively low, and the proportion of the SiCHx group decreased. In general, the surface energies of the films deposited in the HMDSN discharge and the HMDSN/N2 gas mixture discharge exhibited similar features. SEM and AFM evaluations showed high roughness values of 44.5 nm for the film formation in the HMDSN/N2 gas mixture discharge, while the films grown in the HMDSN discharge exhibited a relatively flat surface with a roughness of 24.5 nm. Based on ATR‐FTIR detection, cyclonic plasma‐deposited films deposited in the HMDSN discharge obtained organic moieties, while the films generated in the HMDSN/N2 gas mixture discharge exhibited strong Si–O–Si absorption signals. A possible nano‐organosilicon film growth that prevails in atmospheric pressure plasma deposition is proposed based on atmospheric‐pressure plasma chemistry, nitrogen gas addition, and experimental observations.

Plasma Polymerized Organosilicon Thin Films for Volatile Organic Compound (VOC) Detection

Plasma polymerized (PP) thin films deposited in a soft or intermediate plasma discharge from hexamethyldisiloxane (HMDSO) were developed as sensors for the detection of volatile organic compound (VOC) vapors. Energy dispersive X-ray spectroscopy (EDX) and X-ray reflectometry (XRR) were performed to determine the organosilicon films’ elemental composition and density. Spectroscopic ellipsometry measurements were carried out to determine the refractive index of the films. Quartz crystal microbalance (QCM) and ellipsometry coupled to vapor sorption were used to investigate the sorption mechanism of several VOC vapors into the films as a function of the plasma deposition conditions. The density and the refractive index of the PP-HMDSO films increased with the plasma energy due to a different chemical composition and different proportion of free volumes in the material network. The PP-HMDSO films showed different affinities towards the VOC vapors depending on the plasma discharge energy. The films elaborated in the lowest plasma energy revealed a good sensitivity towards the VOCs, especially toluene (one of the BTEX vapors), compared to the other films deposited under higher plasma energy. In addition, the selectivity between toluene and other non-BTEX VOCs such as heptane and ethanol decreased to become zero while increasing the plasma energy.

Organosilicon Self-Assembled Surface Nanolayers on Zinc-Formation and Their Influence on the Electrochemical and Corrosion Zinc Ongoing.

The adsorption of vinyltrimethoxysilane (VS) on the surface of sputtered (by thermal spraying in vacuum) zinc has been investigated. The adsorption isotherms of VC on zinc from an aqueous solution were obtain. In order to determine the adsorption characteristics of VS molecules and to calculate the heats of adsorption, the obtained adsorption isotherms were mathematically processed in terms of the well-known adsorption approaches (approximations, adsorption isotherms). It has been established that this organosilane was chemisorbed on the surface of freshly deposited zinc after 60 min. After the sample was immersed in the solution, a self-organized organosilicon layer was formed on the metal surface. The application of Fourier transform infrared spectroscopy, atomic-force microscopy, and scanning electron microscopy allowed to us study in detail the interactions between VS molecules and the metal surface and to determine the structural features of the formed surface films. The mechanism of formation of self-assembled surface layers on zinc has been proposed. Electrochemical and corrosion research methods have been used to investigate the anticorrosion characteristics of organosilicon films on zinc. High stability of surface organosilicone layers with respect to the corrosive components of electrolyte action was shown by an infrared spectroscopy study carried out after corrosion tests.

Сравнительный анализ качества маркировки полимерной и кремнийорганической пленки при обработке волоконным наносекундным лазером

To identify products at all stages of production, a code mark is used by two-dimensional DataMatrix barcoding. Due to the fact that there are different types of surfaces, marking with the help of self-adhesive polymer film materials, where the infor-mation is recorded by a laser using the DPM (Direct Part Marking) method, is becoming increasingly popular. These films, called "laser films", are often used in manufacturing, especially in the automotive industry, as they have a number of ad-vantages compared to other information carriers. However, such films (tesa 6930, 3M 7847) are mostly imported and expen-sive, and also have an operating temperature limit of up to 250 °C, which is sometimes insufficient. The article discusses foreign and domestic films, including polymer NPM012 and organosilicon LP2. LP series are a new group of organosilox-ane–based laser films allowing the use of laser marking for parts operating up to 1000 °C. The article provides a compara-tive analysis of the labeling of polymer films and organosilicon films in accordance with international standards of auto-matic identification and data collection technologies. Laser marking is performed using a nanosecond fiber laser with a power of 30 watts and a wavelength of 1,064 microns. DataMatrix (GS1) is used as a barcode according to the Russian sys-tem of marking and keeping track of goods "Honest Mark". Marking quality assessment is carried out by scanning verifier to check the compliance validation for ISO/IEC standards. The article describes the adjustment of laser barcoding technologi-cal parameters for ensuring high-quality marking.

Study of Organosilicon Films Deposited on SAE 1020 Steel by Atmospheric Plasma Jet for Corrosion Protection

Study of Organosilicon Films Deposited on SAE 1020 Steel by Atmospheric Plasma Jet for Corrosion Protection

Atmospheric Pressure Plasma Deposition of Organosilicon Thin Films by Direct Current and Radio-frequency Plasma Jets

Thin film deposition with atmospheric pressure plasmas is highly interesting for industrial demands and scientific interests in the field of biomaterials. However, the engineering of high-quality films by high-pressure plasmas with precise control over morphology and surface chemistry still poses a challenge. The two types of atmospheric-pressure plasma depositions of organosilicon films by the direct and indirect injection of hexamethyldisiloxane (HMDSO) precursor into a plasma region were chosen and compared in terms of the films chemical composition and morphology to address this. Although different methods of plasma excitation were used, the deposition of inorganic films with above 98% of SiO2 content was achieved for both cases. The chemical structure of the films was insignificantly dependent on the substrate type. The deposition in the afterglow of the DC discharge resulted in a soft film with high roughness, whereas RF plasma deposition led to a smoother film. In the case of the RF plasma deposition on polymeric materials resulted in films with delamination and cracks formation. Lastly, despite some material limitations, both deposition methods demonstrated significant potential for SiOx thin-films preparation for a variety of bio-related substrates, including glass, ceramics, metals, and polymers.

Role of the Plasma Activation Degree on Densification of Organosilicon Films.

The possibility of controlling the density of organosilicon films was investigated by tuning the plasma activation degree without providing extra energy to the structure, as usually reported in the literature. For this purpose, thin films were deposited in plasmas fed with hexamethyldisiloxane/Ar mixtures at a total pressure of 9.5 Pa. The power of the radiofrequency excitation signal, P, ranged from 50 to 300 W to alter the average energy of the plasma species while the electrical configuration was chosen to avoid direct ion bombardment of the growing films. In this way, it was possible to evaluate the effect of P on the film properties. Thickness and deposition rate were derived from profilometry data. X-ray energy dispersive and infrared spectroscopies were, respectively, applied to analyze the chemical composition and molecular structure of the layers. Surface topography and roughness were determined by atomic force microscopy while nanoindentation was used to evaluate the mechanical properties of the films. From electrochemical impedance spectroscopy the total resistance to the flow of electrolyte species was derived. The main alteration observed in the structure with changing P is related to the proportion of the methyl functional which remains connected to the Si backbone. Chain crosslinking and film density are affected by this structural modification induced by homogeneous and heterogeneous plasma reactions. The density increase resulted in a film with hardness comparable to that of the silica and more resistant to the permeation of oxidative species, but preserving the organosilicon nature of the structure.

Optimization of cold plasma process parameters for organosilicon films deposition on carbon steel: Study of the surface pretreatment effect on corrosion protection performance in 3 wt% NaCl medium

Organosilicon films were deposited on carbon steel using plasma enhanced chemical vapour deposition (PECVD) process prepared from cold plasma polymerization of 1,1,3,3-tetramethyldisiloxane (TMDSO). The experimental design technique allowed determining the optimal conditions of the plasma process. The effect of different surface pretreatments was investigated using amorphous phosphatation, argon (Ar) and nitrogen (N2) plasma. Coatings showing a hydrophobic character and good adhesion were obtained. Several surface characterization techniques using Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), scanning electron microscopy (SEM), contact angle, cross-cut and surface profilometry were used. The protection efficiency against corrosion of the deposited films has been demonstrated by coupling different electrochemical techniques such as open circuit potential (OCP) and electrochemical impedance spectroscopy (EIS) in 3 wt% NaCl solution. The organosilicon coatings showed good barrier against corrosion even after long immersion time in the aggressive environment, especially when N2 plasma pretreatment is performed.

Characterization of plasma polymerized organosilicon thin films deposited on 316L stainless steel

This study focused on the characterization of the organosilicon films deposited on 316L stainless steel (316L SS) substrate using a plasma polymerization process with hexamethyldisiloxane (HMDSO) precursor and different N2 gas flow rates. The organosilicon film had a C-rich composition as deposited using only HMDSO precursor. The nitrogen content of thin film consecutively increased with increasing N2 flow rate up to 15 sccm. The film deposition rate increased with increasing N2 flow rate. All films exhibited the smooth and pinhole free surfaces. Good adhesion property was obtained for each film after scratch test. Better biocompatibility and cell adhesion was observed for the nitrogen free organosilicon film as compared with that of the untreated 316L SS. Further enhancement of biocompatibility was found for those films with N2 addition. The best biocompatibility, highest transmittance, less hydrophobic surface, and excellent wear resistance were noted for the film grown under 5 sccm N2 flow rate. Such film performance makes it become a promising candidate as the surface coating layer on 316L SS for biomedical application.

Anticorrosion behaviour of amorphous silicon-based coatings prepared by remote cold plasma-assisted chemical vapour deposition process

Organosilicon films were deposited on carbon steel samples using remote microwave nitrogen plasma-assisted chemical vapour deposition. The deposits were obtained using TetraMethyDisoloxane monomer mixed with oxygen. The formed films were characterised using electron microprobe analysis, Fourier transformed infrared spectroscopy, contact angle measurements, scanning electron microscopy and atomic force microscopy. The electrochemical properties of the organosilicon coatings were evaluated using gravimetric experiments next to electrochemical tests. A significant increase in the corrosion resistance behaviour of the organosilicon coated carbon steel specimen was found when the samples were immersed in 3% aqueous sodium chloride solutions. Also, the surface pre-treatment process of carbon steel had an important influence on the morphological and electrochemical behaviour. Argon pre-treatment improves significantly the corrosion resistance or organosilicon coated steel samples. Gravimetric tests in particular showed that samples pre-treated with argon result in lower weight loss and decreased corrosion rates compared to interfaces pre-treated with nitrogen plasma. Keywords: PACVD, carbon steel, organ silicon, corrosion, pre-treatment, electrochemical impedance spectroscopy.

Surface characterization of organosilicon films by low-temperature atmospheric-pressure plasma jet

A new plasma discharge jet was created to carry out the vacuum-free formation of organosilicon thin films at atmospheric pressure. The properties of the plasma-jet-deposited organosilicon film surfaces were evaluated for different plasma powers by contact-angle, scanning electron microscope (SEM), atomic force microscope (AFM), and X-ray photoelectron spectroscopy (XPS) analyses. The surface analysis indicates that the plasma power is the main factor affecting film growth by plasma chemical vapor deposition at atmospheric pressure. Analysis of the surface morphology by SEM and AFM indicates that smooth and uniform organosilicon thin films can be synthesized at a relatively low plasma power. Chemical detection by XPS is used to examine the mainly inorganic characteristics of the plasma-jet-deposited organosilicon films. The results of this investigation demonstrate the possibility of growing vacuum-free plasma-deposited films for large-area processing.

Plasma Enhanced Chemical Vapour Deposition (PECVD) at Atmospheric Pressure (AP) of Organosilicon Films for Adhesion Promotion on Ti15V3Cr3Sn3Al and Ti6Al4V

Plasma Enhanced Chemical Vapour Deposition (PECVD) at Atmospheric Pressure (AP) of Organosilicon Films for Adhesion Promotion on Ti15V3Cr3Sn3Al and Ti6Al4V

Wettability and surface microstructure of polyamide 6 coated with SiOXCYHZ films

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 3.0Pa and HMDSO, oxygen and argon were admitted to the reactor establishing the pressure of 24Pa. 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 (13.56MHz, 150W) to the lowermost sample holder, earthening the top electrode. Deposition was conducted for 1800s. 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.

Large-Area Organosilicon Film Deposition Using Cyclonic Atmospheric Pressure Glow Discharge

Cyclonic atmospheric pressure plasma is developed for chamberless deposition of organosilicon thin films from argon/hexamethyldisoxane (HMDSO) mixtures. The surface properties of the resulting plasma films were investigated as a function of RF plasma power. Film characterization was performed by static contact angle measurement, scanning electron microscopy (SEM), atomic forced microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). It was found the RF plasma power is the key factor that to affects the film growth in the atmospheric pressure plasma chemical vapor deposition process. SEM and AFM results indicated that a smooth, continuous, and uniform surface of organosilicon thin films can be formed at a relatively low plasma power input. XPS indicated that atmospheric-pressure plasma-deposited organosilicon films present mainly inorganic characteristics. This study shows a potential of chamberless film growth at atmospheric pressure to form organosilicon thin films for large-area deposition.

Raman spectra of heterogeneous nanostructures based on organosilicon films

We studied the effect of ion bombardment on the structure of SOG (spin-on-glass) films. We used IR and Raman spectroscopy and plan-view transmission electron microscopy to study the characteristic features of the structural transformation in organosilicon films when bombarded by nitrogen ions. We show that they are heterogeneous and we establish the presence of inclusions of nanocrystalline graphite.

Organosilicon function of gas barrier films purely deposited by inductively coupled plasma chemical vapor deposition system

The novel design of inductively coupled plasma (ICP) source with the parallel electrodes embedded in quartz tubes was developed in this study. The advantages of the inductively coupled plasma chemical vapor deposition (ICPCVD) system were less ion-bombardment effect during the OLED encapsulation process and low cost to manufacture. The encapsulation structure of organosilicon/SiOx thin films deposited on flexible plastic substrates was purely deposited by the single chamber ICPCVD system under various hexamethyldisiloxane (HMDSO) and Ar flow ratios. To investigate the organosilicon film function, the ratio of HMDSO ambient was varied during deposition process and the associated bonding configurations were measured. With an adequate power of 400W and HMDSO atmosphere of 60%, the polymer-like organosilicon films were obtained due to the long chain structures. Finally, the water vapor transmission rate (WVTR) of one dyad barrier decreases to the 0.021g/m2/day due to the stress release of SiOx films caused by the polymer-like films.

Complex analysis of SiOxCyHz films deposited by an atmospheric pressure dielectric barrier discharge

SiOx films are deposited with an atmospheric pressure dielectric barrier discharge (apDBD) using Ar, O2 and different precursor gases (HMDSO and Silane). An experimental study on the influence of the discharge operation parameters on the chemical composition of the deposited films and the vertical structure over the film thickness is carried out by means of SEM, EDX, and ATR–FTIR. Particularly the IR absorption of hydroxyl groups (OH) incorporated in the films is considered in dependence of the deposition conditions. OH can be regarded as an indicator for the barrier properties of the coating or its capability to transport metal ions through the film. The latter process leads to applications in antimicrobial coatings that gradually, over time release e.g. copper or silver ions under wet conditions. The potential of organosilicon films produced in such an atmospheric pressure PECVD with regard to this application is demonstrated for the first time.

Atmospheric Pressure Plasma Discharge for Polysiloxane Thin Films Deposition and Comparison with Low Pressure Process

An atmospheric pressure dielectric barrier plasma discharge has been used to study a thin film deposition process. The DBD device is enclosed in a vacuum chamber and one of the electrodes is a rotating cylinder. Thus, this device is able to simulate continuous processing in arbitrary deposition condition of pressure and atmosphere composition. A deposition process of thin organosilicon films has been studied reproducing a nitrogen atmosphere with small admixtures of hexamethyldisiloxane (HMDSO) vapours. The plasma discharge has been characterized with optical emission spectroscopy and voltage-current measurements. Thin films chemical composition and morphology have been characterized with FTIR spectroscopy, atomic force microscopy (AFM) and contact angle measurements. A strong dependency of deposit character from the HMDSO concentration has been found and then compared with the same dependency of a typical low pressure plasma enhanced chemical vapour deposition process.

Single‐Chamber Deposition of Multilayer Barriers by Plasma Enhanced and Initiated Chemical Vapor Deposition of Organosilicones

AbstractA novel technique, combining the plasma assisted deposition of SiOx‐like coatings with the initiated chemical vapor deposition (iCVD) of organosilicon films in a single‐chamber process, was investigated for the production of multistack barriers against the water vapor permeation. Hexavinyldisiloxane (HVDSO) was used as the film precursor for both kinds of polymerization. iCVD of HVDSO resulted in highly crosslinked and adherent carbon‐rich polymer which reduced the substrate roughness of the substrate, thus acting as a primer for the deposition of the denser C‐depleted uplayer. The plasma ion bombardment of the C‐rich underlayer produced a graded interphase which enhanced the adhesion between the layers and of the multilayer stack to the polymer substrate. The C‐rich interlayers effectively decoupled the defects of the C‐depleted layers, indeed a barrier improvement factor of 100 over the single C‐depleted barrier layer was obtained with a hexalayer structure. magnified image