Organosilicon Coatings Research Articles

Creation of Hydrophilic Organosilicon Coatings and Study of Their Resistance to Factors Accompanying Corona Discharge

Creation of Hydrophilic Organosilicon Coatings and Study of Their Resistance to Factors Accompanying Corona Discharge

Self-growing composite photocatalytic materials for surface self-renewal of marine antifouling coatings

The attachment of marine organisms leads to the problem of marine biofouling. Biofouling can be prevented by using antifouling coatings this provided a low surface energy surface to inhibit the attachment of marine organisms. However, microorganisms inevitably attach during their use, leading to failure of the fouling release coating. To address this problem, we report an innovative strategy of doping photocatalytic materials into silicone coatings. This approach enables the degradation of bacterial carcasses and their secretions, leading to surface self-renewal and extended fouling protection. In this work, we report the controlled crystallisation of Ag-TiO2 nanomaterials (APTES-Ag@TiO2) using various methods influenced by aminopropylsilane. This strategy ensures the full utilisation of sunlight and strong interfacial adhesion, thereby preventing the degradation of photocatalytic performance. APTES-Ag@TiO2 not only has a self-growth effect and excellent photocatalytic performance but also facilitates the degradation of bacterial carcasses, thereby renewing the surface in organosilicon coatings.

Preparation and properties of multiphase composite enhanced functional organosilicon nano-coatings

BackgroundTo improve the inherent stability and environmental compatibility of traditional organosilicon coatings, nano-reinforced composite materials were innovatively designed and synthesized to improve the performance of organosilicon coatings. MethodologyThe silicon dioxide (SiO2) clusters on the surface of graphene oxide (GO) incorporated with calcium carbonate (CaCO3) and dicyclohexylamine nitrite (Dn) nanocomposites (GO@SiO2/CaCO3/Dn) were prepared successfully. Then nanocomposites were integrated into the coating matrix to comprehensively assess their effects on morphology, mechanics, corrosion resistance, and anti-fouling properties. Significant findingsScanning Electron Microscopy (SEM) observations revealed that 4.0 wt.% of the nanocomposite reinforcement led to stratification within the organosilicon coating. The mechanical properties test shows that the hardness, bonding strength, and maximum impact resistance of SiNC2.0 coating is 10.3 HV, 2.8 MPa, and 75 kg·cm, respectively. Electrochemical assessments confirmed that SiNC2.0 displayed superior corrosion resistance, with a corrosion potential (Ecorr) of 0.199 V and a corrosion current density (Icorr) of 7.308 × 10–6 A/cm2. Furthermore, the surface free energy of the nano-coatings is calculated in the range of 20–30 mN/m by contact angle measurement, indicating the anti-fouling and self-cleaning of the organosilicon nano-coatings. Long-term immersion in natural lake water further confirms the stability and durability of the SiNC2.0 coating in real environments.

(Invited) Organosilicon Coatings Made By a Cold Plasma Processes at Atmospheric Pressure for Electrochemical Applications

Cell manufacturing is estimated to account for up to 40% of battery-industry and the related market will grow 14.1% in the next five years (108.4 B$ in 2019). In this context, high-power and stationary large-scale energy storage systems, such as lithium-ion batteries (LiBs), will be essential to make electricity quickly accessible to the power grid. This is particularly true when it comes to power plants located in remote areas or the use of renewable energy sources. Despite their advantages, commercial LiBs are today limited by their environmental and safety hazards. These limitations lead researchers around the world to discover and employ new technologies for safe recycling operations and a better control of the cycling processes. Currently, works are focused on the development of new advanced materials, composite design as well as advanced interfacial layers. In this context, surface modification by cold plasma is one of the most promising solutions to control and modify charge transport mechanisms at the interfaces. Although, the synthesis of nano-layers made by plasma at atmospheric pressure has already received a lot of interest, their use to modify electrochemical devices, such as electrochemical cells remain limited. In this work, the synthesis of organosilicon coatings on composite conductive layers by atmospheric pressure DBD is studied in detail. The influence of different organosilicon molecules has been analysed to highlight the effect of the growth mode as well as chemical functionalities on the operation of the final electrochemical device. The physical and chemical modifications of plasma on the conductive layer as well as the water stability of the coatings were investigated by ATR-FTIR, XRD, SEM and contact angle. Figure 1

Construction and performance of waterborne organosilicon anti-fouling coating based on hydrosilylation

Under the background of “Dual Carbon” strategy, the coating technology of silicon-based materials replacing carbon-based materials has become a research hotspot. Owing to high-viscosity characteristic of raw materials involving divinyl-terminated polydimethylsiloxane (ViPDMSVi) and reinforcing components, existing approaches for the preparation of organosilicon coatings by hydrosilylation still consume a large amount of organic solvents, causing environmental pollution and inconsistent with the low-carbon strategy. Herein, a robust strategy to prepare hydrosilylation waterborne organosilicon coatings via rational design of the emulsification system to obtain two-component aqueous emulsions is reported. In this strategy, two reactive organosilicon surfactants were synthesized and compounded with corresponding anionic surfactants for emulsification of vinyl organosilicon components and polymethylhydrosiloxane (PMHS), respectively. The resultant two emulsions were cured via hydrosilylation to obtain the desired coating. Additionally, vinyl MQ resin was selected as reinforcing component to increase the density of the coating. The facts that water, ethanol, mud water and other common liquids can slide off cleanly, and oily markers on the coating surface can be easily wiped off, indicate the outstanding anti-fouling properties of the coating. Furthermore, even under various harsh environments such as high temperature, ultraviolet radiation and chemical corrosion, the coating still shows good anti-fouling performance. This work opens up a viable avenue for the preparation of waterborne organosilicon anti-fouling coatings.

Study of the photodegradation of polypropylene: Effect of the silane coupling agents as organosilicon coatings in TiO2 fillers, evaluation of the thermomechanical properties

In this work, the effect of the side group of a series of silane coupling agents, as well as the subsequent anchoring of an imidazole derivative, for TiO2 particles, within the polypropylene polymeric matrix, with emphasis on their mechanical properties and their crystallization kinetics, and their rate of degradation. Differences were the following: the 3-Glicydoxypropyltrimethoxysilane was the best in photostability overall. On the other hand, 3-Chloropropyltrimethoxysilane promoted the degradation. All the other silane coupling agents avoided the anatase's photocatalytic activity, inhibiting the polymer matrix's degradation.

Plasma-Deposited Organosilicon Hydrophobic Coatings on Cellulosic Materials for Wet Packaging Applications

Non-toxic organosilicon coatings with hydrophobic properties were deposited on Kraft paper films using atmospheric-pressure dielectric barrier discharge. In order to assess the applicability of the plasma-deposited coating in the food packaging industry, its stability in different liquids (i.e., food simulants) was studied. Chemical analyses reveal that the food simulants, namely, de-ionized water, acetic acid, ethanol, and heptane, do not significantly alter the chemical composition or the hydrophobicity of the coatings. Based on inductively coupled plasma-optical emission spectroscopy analyses, the amount of Si released from the plasma-deposited coating is less than that typically detected in tap water. Overall, the results obtained suggest that hydrophobic plasma-deposited organosilicon coatings have great potential for use in food and wet packaging applications, especially considering their environmentally friendly character.

Investigation of the Wear Resistance of Anticorrosive Organosilicon Coatings under Various Operating Conditions

Investigation of the Wear Resistance of Anticorrosive Organosilicon Coatings under Various Operating Conditions

Soft polymerization of hexamethyldisiloxane by coupling pulsed direct‐liquid injections with dielectric barrier discharge

AbstractThis work examines the combination of pulsed direct‐liquid injections with dielectric barrier discharge at atmospheric pressure for the deposition of organosilicon coatings using hexamethyldisiloxane (HMDSO) as the precursor and nitrogen as the carrier gas. In such conditions, deposition relies on the charging of micrometer droplets and their transport toward the substrate by the Coulomb force. The thin‐film morphology and extent of precursor fragmentation are strongly linked to the amount of energy provided by the filamentary discharge to HMDSO droplets. While cross‐linked and smooth coatings were achieved at low energies as in standard gas phase plasma polymers, viscous and droplet‐like structured thin films were deposited at higher energies. The latter material is attributed to the soft polymerization of HMDSO droplets related to plasma–droplet interactions.

Study of the fillers influence on the organosilicon polymers resistance to high temperatures

Organosilicon varnishes, such as polymethylphenylsiloxane and polyaluminomethylphenylsiloxane, filled with modified clay minerals are the object of research The most vulnerable place of the organosilicon coating is insufficient mechanical properties (hardness, impact strength, etc.) and low adhesive strength of the film to the surface, especially when operating at elevated temperatures. Various oxides, ceramic compounds, natural and synthetic silicate materials are introduced into organosilicon compositions to improve the specified properties. But only individual units can comprehensively improve both the mechanical and heat-resistant properties of organosilicon compounds although the range of such materials is quite wide. The clay minerals palygorskite, which is classified as an intermediate type between strip and layered silicates, and montmorillonite from the subclass of layered silicates, which have a natural high dispersion, were used as fillers during the study. The choice of palygorskite and montmorillonite is explained by the sufficient study of their behavior in organic environments by a number of scientists, availability and economic advantages for introduction into production. Existing clay minerals, which are traditionally used to solve the problem of improving the physical and mechanical properties of organosilicon coatings, are not sufficiently active due to the hydrophilic properties of the particles surface. Based on this, a modifier that has proven itself well in this field was used for the study. A number of compositions of heat-resistant organosilicon varnishes with modified fillers based on the above-mentioned clay minerals were obtained. It was established that the introduction of modified forms of natural aluminosilicates contributes to the increase of temperature resistance in filled coatings, compared to coatings made of pure polymer. At the same time, the best effect is achieved when using montmorillonite. This is related with the fact that the proposed compositions of polymethylphenylsiloxane varnish and montmorillonite have a number of features, in particular, the highest comprehensive result of simultaneous improvement of the physical, mechanical and thermal properties of the specified coatings. It is possible to obtain compositions with stable physico-mechanical properties, as they withstood heat treatment at 400 °C for 100 hours without visible changes in integrity, due to the introduction of the optimal amount of modified montmorillonite into organosilicon varnishes KO-08K and KO-921. Compared to similar heat-resistant polymethylphenylsiloxane varnishes, longer service life at elevated temperatures is ensured.

Stability of trimethylsilyl acetate-based plasma polymers towards atmospheric and water environments

In the present work, SiOxCyHz coatings were prepared in capacitively coupled RF glow discharge from gaseous mixture of trimethylsilyl acetate (TMSAc) monomer and oxygen. Properties of thin solid films prepared using continuous wave (CW) plasma and pulsed wave (PW) plasma were examined, including long–term stability in contact with air and water environments. The presented study proves that it is possible to prepare organosilicon coatings showing properties in a wide range from soft organic polymeric structures to materials similar to SiO2 with Martens hardness of 4 GPa. The content of carbon species in organosilicon structure and water contact angle (WCA) decreased with increasing oxygen ratio from 7.7 % to 75.0 %. The water contact angle of TMSAc-based coatings prepared in CW mode decreased from 95° to 76°. The application of pulsed mode using an oxygen ratio of 50 % and pulse repetition frequencies in the range of 0.33 Hz to 300 Hz led to materials with hydrophobic character (WCA in range of 86°–94°) with increased content of CHx and Si-CH3 structures in comparison to CW mode. This study proves that the aging mechanism significantly depends on deposition parameters. The increase of oxygen ratio, as well as the increase of pulse repetition frequency, led to the higher resistance towards the atmospheric environment. On the other side, organosilicon coatings prepared in CW mode using high oxygen ratios (50–75 %) showed significant delamination after immersion in water. However, the use of PW plasma for the preparation of SiOxCyHz thin films significantly improved the stability of resulting materials under water environment.

Исследование износостойкости антикоррозионных кремнийорганических покрытий в различных условиях эксплуатации

Methods for protecting machine parts from corrosion, types of protective anticorrosive coatings and types of anti-icing materials used in Russian cities, as well as their effect on the rate of corrosion extension are discussed. The results of determining the frictional properties of anticorrosive organosilicon coatings modified with various dispersed fillers under conditions of dry and liquid friction with water and liquid reagent are presented. It is shown that the introduction of mica, nanotubes, and aluminum hydroxide into the composition of the organosilicon matrix made possible to reduce values of the friction coefficient in both dry and liquid friction.

Cold plasma assisted deposition of organosilicon coatings on stainless steel for prevention of adhesion of Salmonella enterica serovar Enteritidis

The persistence of Salmonella enterica on abiotic surfaces in hospitals and the agri-food industries leads to several infections worldwide. In this context, this work aimed to study the adhesion of S. Enteritidis on plasma-modified stainless steel to prevent biofilm-associated-infections. Surface modification was achieved by the elaboration of organosilicon coatings from the monomer 1,1,3,3-tetramethyldisiloxane, mixed with oxygen, using a flowing nitrogen microwave post-discharge plasma polymerization technique. The effect of cold plasma parameters on the properties of the coatings, the coated surface topography and S. Enteritidis cell adhesion was studied. The results showed that the surface topography influenced the bacterial adhesion rate. Indeed, rough surfaces did not repel S. Enteritidis since the number of attached cells on these coatings was between 30 ± 4 to 65 ± 4 bacteria per microscopic field. Otherwise, smoother surfaces demonstrated an anti-adhesive character since the number of attached cells was almost nil on these coatings.

Heat-Resistant Coatings of Heat-Shielding Tiles

We consider the principles of creating organosilicon natural-drying coatings with thermal resistance up to 1200°C and minimal internal stresses and present the design of a heat-shielding tile for a life-saving appliance capable of overcoming a burning oil slick. The necessary heat-shielding properties of the tile, providing an increase in the cladding temperature of the universal life-saving equipment of no more than 30°C under heating of the outer tile surface up to 1150°C for 10 min, are achieved by means of development of heat-resistant organosilicon coatings.

Deposition of organosilicon coatings from trimethylsilyl acetate and oxygen gases in capacitively coupled RF glow discharge

The aim of the present work was to prepare SiOxCyHz coatings in capacitively-coupled RF glow discharge from gaseous mixture of trimethylsilyl acetate (TMSAc) monomer and oxygen. The properties of deposited coatings have been investigated using several characterization methods. The presented study proves that properties of TMSAc-based thin films are significantly dependent on the monomer ratio in TMSAc/O2 mixture which varied from 25.0% to 92.3%. Using a low TMSAc ratio (high content of oxygen gas) resulted in organosilicon materials similar to SiO2 in terms of chemical composition and mechanical properties. Increasing the fraction of TMSAc in gaseous mixture led to the formation of more organic polymeric structures enriched with carbon atoms bonded in CHx chains. Values of Martens hardness decreased from 3.97 to 0.76 GPa with increasing TMSAc fraction from 25.0% to 92.3%. The degree of hydrophobicity of prepared coatings evolved in accordance with observed structural changes corresponding to applied monomer ratios. The water contact angle gradually increased from 75.0° to 95.3° with increasing TMSAc fraction. The prepared TMSAc plasma polymers became more hydrophobic with more intensive integration of hydrocarbon species into the surface structure.

Icing Intensity of Passive Organosilicon Anti-Icing Coatings

The results of experimental studies of anti-acing property of passive organosilicon coatings with hydrophobic groups are presented. The high efficiency of that coating with hydrophobic groups -CF3 is found. It is shown that such coatings can provide low icing intensity and, at the same time, high abrasion resistance.

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.

Atmospheric-pressure-plasma-enhanced fabrication of nonfouling nanocoatings for 316 stainless steel biomaterial interfaces

Atmospheric-pressure plasma, which was generated with electrical RF power, was fed to a tetramethyldisiloxane/argon gas mixture to prepare bioinert organosilicon coatings for 316 stainless steel. The surface characteristics of atmospheric-pressure-plasma-deposited nanocoatings were evaluated as a function of RF plasma power, precursor gas flow, and plasma working distance. After surface deposition, the chemical features, elemental compositions, and surface morphologies of the organosilicon nanocoatings were examined. It was found that RF plasma power and plasma working distance are the essential factors that affect the formation of plasma-deposited nanocoatings. Fourier transform infrared spectroscopy spectra indicate that the atmospheric-pressure-plasma-deposited nanocoatings formed showed inorganic features. Atomic force microscopy analysis showed the surface roughness variation of the plasma-deposited nanocoating at different RF plasma powers and plasma working distances during surface treatment. From these surface analyses, it was found that the plasma-deposited organosilicon nanocoatings under specific operational conditions have relatively hydrophobic and inorganic characteristics, which are essential for producing an anti-biofouling interface on 316 stainless steel. The experimental results also show that atmospheric-pressure-plasma-deposited nanocoatings have potential use as a cell-resistant layer on 316 stainless steel.

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.

Organosilicon and Titanium Oxide Coatings for Mitigation of CaCO3 Depositions

Fouling reduces the thermal efficiency of heat transfer units, and it causes economic losses and has a marked effect on CO2 releases and thus on climate change. In order to improve the energy efficiency, deposition formation (precipitation and crystallization) onto the heat transfer surfaces is going to be mitigated. A way to achieve this goal is the development of new surface materials with controlled chemical composition and morphology. In this study, formation mechanism of CaCO3 depositions was investigated on modified (–CH3 and –COOH) organosilicon (SiOC), and anatase and rutile TiO2 surfaces. The results were compared to those of stainless steel surfaces. Based on the molecular modeling results, anatase and –COOH functionalized SiOC coatings are promising materials for mitigation of fouling caused by CaCO3.