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The luminescence quenching by aggregation of carbon dots (CD) could be solved by functionalizing the surface with an alkoxysilane, bounding the nanoparticle directly in the polymer network.The reaction was monitored with ATR-FTIR and bacterial cellulose (BC) was coated with the precursor using sol-gel route, showing blue luminescence of CD.

Organic–inorganic coating has been desirable for practical applications in electrochemistry and analytical science. Up to this investigation, a report of a “flowerlike” structure made from organic ...

The organic-inorganic hybrid coating was fabricated for anti-corrosion application using bisphenol A diglycidyl ether (BADGE) epoxy resin with inorganic silica nanoparticles prepared by sol-gel method. The precursor, tetraethyl orthosilicate (TEOS) formed via hydrolytic condensation the silica dispersed in the protective coating on the metal substrate that could prevent the permeation of corrosive media. In order to increase the functionality of the coating, the photocatalyst zinc oxide (ZnO) nanoparticles were added to bestow the light degradation on the coating. The as-fabricated nanoparticles and coatings were analyzed using Fourier Transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV–vis spectrum (UV–vis) analysis. The anti-corrosion performance of the organic-inorganic hybrid coating was investigated by electrochemical impedance spectroscopy (EIS) and salt spray tests. Noteworthily, EIS results showed that the epoxy-silica organic-inorganic coating was109Ωcm2,which could increase the impedance modulus (at 0.01 Hz) of Q215 steel by about 7 orders of magnitude after immersion in 3.5 wt% NaCl aqueous solution for 96 h. The salt spray test results showed that metal substrate was still not completely corroded after 68 days. In addition, the addition of ZnO to the coating has photo-degradation effect on methyl orange and the photo-degradation efficiency can reach 55%.

Organophosphate pesticides (OPs) have been found as contaminants in surface and ground waters, soil, and agricultural products. Because OPs are toxic compounds, monitoring of OPs in groundwater is necessary to allow for real-time remediation. Various types of polymer-coated sensors are being investigated for the rapid detection/monitoring of OPs in groundwater. The focus of this paper is on analyzing the sensor response of an acoustic wave device for the detection of organophosphate pesticides in aqueous solutions to determine whether the analyte absorption is penetration limited or diffusion limited. In this work, kinetic studies for the absorption of organophosphates (parathion-methyl, parathion, and paraoxon) from aqueous solutions into a hybrid organic/inorganic chemically sensitive layer [bisphenol A–hexamethyltrisiloxane (BPA-HMTS)] coating are conducted using guided shear horizontal surface acoustic wave sensor platforms on 36° rotated Y-cut LiTaO 3 . The objective of the studies is to provide an understanding of the underlying physics of the sensor response. The sensor data are analyzed within the context of two absorption models: penetration-limited and diffusion-limited absorptions. It is shown that the absorption process is rate-limited by penetration with a concentration independent absorption time constant or mass transfer coefficient. The absorption time constants for parathion-methyl, parathion, and paraoxon are calculated. It is seen that even though paraoxon is only 3.8% smaller (by volume) than parathion, its absorption time constant (∼10.5 ± 2.1 min) is, for the same coating thickness, at least 50% faster than parathion (∼32.5 ± 1.6 min). On the other hand, parathion-methyl, which is 9.5% smaller than paraoxon, exhibited about the same absorption time (∼8.3 ± 0.5 min) as paraoxon. This difference in transient information can be used to improve analyte recognition (between parathion/paraoxon and parathion/parathion-methyl).

In the past, a very popular way to reduce the corrosion rate of zinc was the use of chemical conversion layers based on . However, the use of chromium salts is now restricted because of environmental protection legislation. Previous research investigated the optimum corrosion resistance of galvanized steel treated with an organic/inorganic solution containing Si. The result showed that the optimum corrosion resistance occurred by heat treatment of in 5 min. In this study, one organic and three hybrid organic/inorganic coating solutions were applied to cold-rolled (CR) carbon steel. The coatings were then evaluated for corrosion resistance under a salt spray test. The coating solutions examined in this study consisted of urethane-only, urethane-Si, urethane-Si-Ti, and urethane-Si-Ti-epoxy. The results of the 7 h salt spray test showed that the urethane-Si-Ti and urethane-Si-Ti-epoxy coating solutions had superior corrosion resistance on CR steel.

Organic–inorganic multilayer coating containing organically modified silicates, epoxy resins and TiO2 nanocontainers loaded with 8-hydroxyquinoline were produced on AA2024-T3 substrates via dip coating method. The parameters of the curing temperature and time were optimized via variation in a widespread range in order to realize coatings with best anticorrosive properties. Curing temperature at 110 °C for 24 h presented the best anticorrosive behavior. The morphology of the coating was examined via scanning electron microscopy. The composition of the coatings was determined by energy dispersive X-ray analysis and Fourier transform infra-red spectroscopy. Furthermore, the coatings were exposed to corrosive environment and evaluated by electrochemical impedance spectroscopy. We demonstrate that the presence of loaded TiO2 nanocontainers enhances the anticorrosive properties of the coatings; specifically, the total impedance values were increased about two orders of magnitude compare to the bare substrate after 400 h of exposure to aggressive environment.

The mechanical properties of various inorganic organic films were studied and compared in order to investigate the relation between structural modifications and the mechanical behavior. Films were prepared by a sol–gel process and spin-coated on silicon substrate. The organic–inorganic hybrid is composed of a mixture of colloidal silica and organosiloxane precursors. The functionality of the organosiloxane and the nature of its organic part have been modified to obtain a structural change. Mechanical properties were studied using nanoindentation. Analysis of the strength evolution as a function of depth of indentation shows the layer hardness and elastic modulus. Moreover, coating and interface toughness and residual stresses were determined by a time resolved study of energy dissipation during indentation. The structural changes were determined using liquid and solid 29Si NMR spectroscopy. Quantity of partially and fully condensed species in the deposited sol and final solid are discussed in relation to the mechanical properties.

A novel alumina-based hybrid organic-inorganic sol-gel coating was first developed for solid-phase microextraction (SPME) from a highly reactive alkoxide precursor, aluminum sec-butoxide, and a sol-gel-active organic polymer hydroxyl-terminated polydimethylsiloxane (OH-TSO). The underlying mechanism was discussed and confirmed by IR spectra. The porous surface structure of the sol-gel coating was revealed by scanning electron microscopy. A detailed investigation was conducted to evaluate the remarked performance of the newly developed sol-gel alumina-OH-TSO hybrid materials. In stark contrast to the sol-gel silica-based coating, the alumina-based coating demonstrated excellent pH stability. In addition, good thermal resistance and coating preparation reproducibility are also its outstanding performance. As compared to silica-based hybrids material, the ligand exchange ability of alumina makes it structurally superior extraction sorbents for polar compounds, such as fatty acids, phenols, alcohols, aldehydes and amines. Practical applicability of the prepared alumina-OH-TSO fiber was demonstrated through the analysis of volatile alcohols and fatty acids in beer. The recoveries obtained ranged from 85.7 to 104% and the relative standard deviation values for all analytes were below 9%.

The moisture diffusion in globtop material for a chip-on-board (COB) package coated with SiNx and silicone, respectively, or coated with SiNx plus silicone were measured by embedding a humidity sensor in the globtop and recording the capacitive change in three different temperature/humidity environments. The experimental results were simulated by Fick’s diffusion law with finite-element method modeling. The moisture diffusion coefficients and activation energies were calculated to quantitatively compare the moisture-resistance effects of different coatings. For example, at 85°C/85% RH, the moisture diffusion coefficients for the uncoated reference, SiNx-coated, silicone-coated, and silicone/SiNx double-layered coated samples are 1E-5, 0.8E-5, 0.7E-5, and 0.2E-5 mm2/s, respectively. The experimental and simulation results show that double-layered coating with silicone/SiNx has excellent moisture-resistance properties because it not only smoothes the steps on a printed circuit board (PCB) but also keeps the good moisture resistance of the inorganic films.

The effects of drying, aging and curing on an organic - inorganic coating deposited on float glass substrates were analyzed. Methyltrimethoxysilane was used to immobilize parts of the network connections and silica particles were used as seeds for the nucleation of the gel structure. The coating was produced under acidic conditions to enhance the hydrolysis reaction. The coatings were deposited using a spin-coating technique. The dependence of the elastic modulus, hardness, fracture toughness and residual stress obtained by indentation on the preparation conditions is reported. In addition results obtained by X-ray diffraction (XRD), Atomic Force Microscopy (AFM), X-ray Photon Spectroscopy (XPS) and Infrared-Spectroscopy are analyzed.

The effects of drying, aging and curing on an organic - inorganic coating deposited on float glass substrates were analyzed. Methyltrimethoxysilane was used to immobilize parts of the network connections and silica particles were used as seeds for the nucleation of the gel structure. The coating was produced under acidic conditions to enhance the hydrolysis reaction. The coatings were deposited using a spin-coating technique. The dependence of the elastic modulus, hardness, fracture toughness and residual stress obtained by indentation on the preparation conditions is reported. In addition results obtained by X-ray diffraction (XRD), Atomic Force Microscopy (AFM), X-ray Photon Spectroscopy (XPS) and Infrared-Spectroscopy are analyzed.

An organic–inorganic hybrid titania-hydroxy-terminated silicone oil (titania-OH-TSO) stir bar coating was prepared by sol–gel method. The extraction performance of titania-OH-TSO coated stir bar was evaluated and compared with poly(dimethysiloxane) (PDMS), poly(dimethysiloxane)–divinylbenzene (PDMS–DVB), poly(dimethysiloxane)–β-cyclodextrin (PDMS–β-CD) and C18 coated stir bar with five polar drugs of abuse including amphetamine (PA), methamphetamine (MA), 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA) and ketamine (Ke) as the model analytes. The experimental results revealed that the titania-OH-TSO coated stir bar exhibited highly pH-resistant ability, good preparation reproducibility, superior selectivity and high extraction efficiency for the target compounds. Based on this fact, a new method of titania-OH-TSO coated stir bar sorptive extraction (SBSE) combined with high performance liquid chromatography (HPLC)–ultraviolet visible (UV) detection was developed for the analysis of five drugs of abuse in urine samples. The factors affecting the extraction efficiency of SBSE such as sample pH, desorption solvent, sample volume, extraction time, desorption time, stirring rate and ionic strength were investigated and the optimal extraction conditions were established. Under the optimized conditions, the limits of detection (LODs) for titania-OH-TSO coated SBSE–HPLC–UV determination of five polar drugs of abuse were in the range of 2.3–9.1 μg/L with relative standard deviations (RSDs) ranging from 7.3 to 8.9% (c = 300 μg/L, n = 6), and all of the target compounds exhibited good linearity over a concentration range of 30–3000 μg/L. The developed method was applied to the determination of amphetamines and Ke in urine samples of drug abusers with satisfactory results.

Rapid detection of organophosphates pesticides (OPs) in groundwater is necessary to allow for real-time monitoring and cleanup. Detection of OPs in the liquid phase has already been demonstrated using poly(epichlorohydrin) [PECH] and polyurethane as the sensing layer. However, the response times are relatively long, on the order of hours. In this work, a hybrid organic/inorganic chemically sensitive layer [bisphenol A-hexamethyltrisiloxane (BPA-HMTS)] is synthesized and investigated for the rapid detection and analysis of organophosphate pesticides. Direct chemical sensing in aqueous solutions is performed using the guided shear horizontal surface acoustic wave sensor platform on 36° rotated Y-cut LiTaO 3 . It is shown that, for the same coating thickness, a 60% reduction in sensor response time is achieved without a significant reduction in sensitivity when compared with PECH. Considering the glass transition temperature, T g , for the polymers, it is seen that the faster sensor response exhibited by the BPA-HMTS coating is due to the porous siloxane backbone, HMTS. Furthermore, sensor signal analysis in the form of the extended Kalman filter (EKF) is employed on-line during the detection process. This allows for the steady-state sensor response and absorption time constant to be extracted on-line well before equilibrium, thus further reducing the time required for analyte identification and quantification. 500 µg/L of parathion has been detected and a limit of detection of 20 µg/L (ppb) for parathion and 100 µg/L (ppb) of paraoxon is reported for the present non-optimized sensor.

Sol-gel titania-poly(dimethylsiloxane) (TiO2-PDMS) coating was developed for capillary microextraction (CME) to perform on-line preconcentration and HPLC analysis of trace impurities in aqueous samples. A method is presented describing in situ preparation of the titania-based sol-gel PDMS coating and its immobilization on the inner surface of a fused silica microextraction capillary. To perform CME-HPLC, the sol-gel TiO2-PDMS capillary was installed in the HPLC injection port as an external sampling loop, and a conventional ODS column was used for the liquid chromatographic separation. The target analytes were extracted on-line by passing the aqueous sample through this sampling loop. The sol-gel titania-PDMS coated capillaries were used for on-line extraction and HPLC analysis of polycyclic aromatic hydrocarbons, ketones, and alkylbenzenes. The extracted analytes were then transferred to the HPLC column using an organic-rich mobile phase followed by HPLC separation via gradient elution. To our knowledge, this is the first report on the use of sol-gel titania-based organic-inorganic material as a sorbent in capillary microextraction. The newly developed sol-gel titania-based CME coatings demonstrated excellent pH stability and enhanced extraction capability over the commercial GC coatings that are conventionally used for the same purpose. Extraction characteristics of a sol-gel titania-PDMS capillary remained practically unchanged after continuous rinsing with a 0.1 M NaOH solution (pH 13) for 12h.

The effects of drying, aging and curing on an organic - inorganic coating deposited on float glass substrates were analyzed. Methyltrimethoxysilane was used to immobilize parts of the network connections and silica particles were used as seeds for the nucleation of the gel structure. The coating was produced under acidic conditions to enhance the hydrolysis reaction. The coatings were deposited using a spin-coating technique. The dependence of the elastic modulus, hardness, fracture toughness and residual stress obtained by indentation on the preparation conditions is reported. In addition results obtained by X-ray diffraction (XRD), Atomic Force Microscopy (AFM), X-ray Photon Spectroscopy (XPS) and Infrared-Spectroscopy are analyzed.

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The electric vehicle and energy storage markets have grown rapidly in recent years. Thermal runaway caused by malfunctioning Li-ion batteries is an urgent issue with many causes (e.g., mechanical, electrical, and thermal abuse). The most common cause of thermal runaway is the formation of an internal short circuit because of damage to the separator. There has been significant effort to improve the design of separators, but to our knowledge, only inorganic nanoparticle coatings are used in commercial Li-ion batteries. Here, hybrid organic/inorganic coating layers are synthesized in a pilot-scale process that was developed from a crosslinkable polyamide-imide synthesis technique. The fabrication process is optimized to achieve reproducible hybrid organic/inorganic coating layers that are thin (≤4 μm), permeable (≤250 s/100 cc), and thermally stable beyond 150 °C. The hybrid coating layer is applied to mini-18650 Li-ion cells to show that the discharge capacity did not change at low discharge rates, and the retention capacity after 500 cycles was better than that of the reference cells used for comparison. This work demonstrates that a novel hybrid coating layer has the potential to improve the stability of commercial Li-ion batteries.

A hybrid material of polystyrene (PS)–ZrO2 was developed by the sol–gel technique and deposited by spin-coating on AM60 and AM60–AlN nanocomposite surfaces to enhance corrosion resistance in marine environments.PS–ZrO2 with an average thickness of ≈305±20nm was dispersed homogeneously, presenting isolated micro–nano-structure defects with air trapped inside, which led to an increase in roughness (≈4 times). The wettability of the coated substrates was close to the hydrophobic border (θCA=90°–94°). The coated samples were exposed for 30 days to SME solution, simulating the marine–coastal ambience. The initial pH = 7.94 of the SME shifted to more alkaline pH ≈ 8.54, suggesting the corrosion of the Mg matrix through the coating defects. In the meantime, the release of Mg2+ from the PS–ZrO2-coated alloy surfaces was reduced by ≈90% compared to that of non-coated. Localized pitting attacks occurred in the vicinity of Al–Mn and β–Mg17Al12 cathodic particles characteristic of the Mg matrix. The depth of penetration (≈23 µm) was reduced by ≈85% compared to that of non-coated substrates. The protective effect against Cl ions, attributed to the hybrid PS–ZrO2-coated AM60 and AM60–AlN surfaces, was confirmed by the increase in their polarization resistance (Rp) in 37% and 22%, respectively, calculated from EIS data.

Reinforcement steel extensively applied in civil construction is susceptible to corrosion due to the carbonation process in reinforced concrete and chloride ions diffusion. Epoxy-silica-based coatings are a promising option to guarantee the long-term stability of reinforced concrete structures. In this study, the influence of the proportion between the poly (bisphenol-A-co-epichlorhydrin) resin (DGEBA) and the curing agent diethylenetriamine (DETA) on the structural, morphological, and barrier properties of epoxy–silica nanocomposites were evaluated. To simulate different stages of concrete aging, electrochemical impedance spectroscopy (EIS) assays were performed for coated samples in a 3.5 wt.% NaCl solution (pH 7) and in simulated concrete pore solutions (SCPS), which represent the hydration environment in fresh concrete (SCPS2, pH 14) and after carbonation (SCPS1, pH 8). The results showed that coatings with an intermediate DETA to DGEBA ratio of 0.4, presented the best long-term corrosion protection with a low-frequency impedance modulus of up to 3.8 GΩ cm2 in NaCl and SCPS1 solutions. Small-angle X-ray scattering and atomic force microscopy analysis revealed that the best performance observed for the intermediate DETA proportion is associated with the presence of larger silica nanodomains, which act as a filler in the cross-linked epoxy matrix, thus favoring the formation of an efficient diffusion barrier.

Made available in DSpace on 2022-05-01T13:41:37Z (GMT). No. of bitstreams: 0 Previous issue date: 2022-02-25 In the absence of preventive maintenance, corrosion of structural steel by the deterioration of the passive layer due to exposure to aggressive environments is the main failure factor of reinforced concrete. To overcome economic, safety, and environmental implications, present research efforts focus on eco-friendly organic-inorganic hybrid coatings to achieve effective protection of reinforcing steel. Nanostructured PMMA (poly(methyl methacrylate))-silica coatings developed by combining reactions of the polymerization of methyl methacrylate and 3-[(methacryloxy)propyl]trimethoxysilane with the sol-gel hydrolytic condensation of tetraethyl orthosilicate using isopropanol as a solvent represent a promising approach to accomplish this goal. The nanoscale dispersion of silica nodes covalently conjugated with PMMA chains led to transparent, homogeneous, and pore-free coatings deposited with a thickness of 15 μm on 2D and 3D reinforcing steel. Mechanical, thermal, and surface analyses showed a strong adhesion of the coating to the substrate surface (15.9 MPa), a thermal stability of up to 256 °C, and a contact angle of about 75°. Electrochemical assays in standard 3.5 wt % NaCl solution, simulated carbonated, and alkaline concrete pore solutions confirmed effective corrosion protection, with an impedance modulus of up to 100 Gω cm2(at 4 mHz) and a lifetime of more than 670 days. Hence, PMMA-silica hybrid coatings are an eco-friendly and efficient alternative to protect reinforcing steel against corrosion, helping to prevent structural failures and fatal accidents. São Paulo State University (UNESP) Institute of Chemistry São Paulo State University (UNESP) Institute of Chemistry

Made available in DSpace on 2022-05-01T09:30:59Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-12-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Organic-inorganic hybrids are considered an effective and environmentally compliant alternative to chromate-based anticorrosive coatings, currently banned due to the high toxicity of hexavalent chromium. In this work, hybrid nanocomposites based on poly(methyl methacrylate) (PMMA), covalently bonded to cerium oxide nanoparticles through the 2-hydroxyethyl methacrylate (HEMA) coupling agent, were tailored by carefully tuning the inorganic colloidal precursor to provide films with active corrosion protection for metallic substrates. Lithium hydroxide was exploited as oxidizing agent of cerium nitrate to form ceria nanoparticles. Precursor solutions and solid nanocomposites with different LiOH to Ce(NO3)3.6H2O molar ratios were analyzed using spectroscopic and electron microscopy techniques and theoretical simulations. Electrochemical impedance spectroscopy (EIS) was used to study the anticorrosive performance of the coatings on carbon steel and 7075 aluminum alloy. The results showed that increasing amounts of LiOH lead to the formation of higher ceria content and larger primary nanoparticles, ranging from 1.7 to 2.8 nm. The homogenous ~20 μm-thick coatings present excellent anticorrosive performance on carbon steel and AA7075 substrates. Coatings on carbon steel with low LiOH loading (1Li:1Ce) showed long-term durability and high impedance modulus of up to 29 GΩ cm2 after 1 day in saline solution. On the AA7075 alloy, the presence of larger cerium oxide particles at higher LiOH content (3Li:1Ce) acted as effective reservoirs of cerium ions, providing high barrier coatings (395 GΩ cm2) with active corrosion protection. São Paulo State University (UNESP) Institute of Chemistry São Paulo State University (UNESP) Institute of Chemistry CAPES: 001 CNPq: 142305/2020-0 FAPESP: 2015/09342-7 FAPESP: 2015/11907-2 FAPESP: 2019/13871-6 CNPq: 307905/2018-7 CNPq: 309419/2020-4 CNPq: 421081/2016-3 CNPq: 424133/2016-4 CNPq: 430758/2018-9

Made available in DSpace on 2020-12-12T02:34:44Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-05-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Ti6Al4V is the mostly applied metallic alloy for orthopedic and dental implants, however, its lack of osseointegration and poor long-term corrosion resistance often leads to a secondary surgical intervention, recovery delay and toxicity to the surrounding tissue. As a potential solution of these issues poly(methyl methacrylate)-silicon dioxide (PMMA-silica) coatings have been applied on a Ti6Al4V alloy to act simultaneously as an anticorrosive barrier and bioactive film. The nanocomposite, composed of PMMA covalently bonded to the silica phase through 3-(trimethoxysilyl)propyl methacrylate (MPTS), has been synthesized combining the sol-gel process with radical polymerization of methyl methacrylate. The 5 μm thick coatings deposited on Ti6Al4V have a smooth surface, are homogeneous, transparent, free of pores and cracks, and show a strong adhesion to the metallic substrate (11.6 MPa). Electrochemical impedance spectroscopy results proved an excellent anticorrosive performance of the coating, with an impedance modulus of 26 GΩ cm2 and long-term durability in simulated body fluid (SBF) solution. Moreover, after 21 days of immersion in SBF, the PMMA-silica coating presented apatite crystal deposits, which suggests in vivo bone bioactivity. This was confirmed by biological characterization showing enhanced osteoblast proliferation, explained by the increased surface free energy and protein adsorption. The obtained results suggest that PMMA-silica hybrids can act in a dual role as efficient anticorrosive and bioactive coating for Ti6Al4V alloys. São Paulo State University (UNESP) Institute of Chemistry Federal University of Piauí (UFPI) Interdisciplinary Laboratory for Advanced Materials (LIMAV) Department of Materials Engineering Department of Chemical Engineering Northeastern University São Paulo State University (UNESP) Institute of Chemistry CNPq: 303752/2017-3

Organic–inorganic hybrid materials can be defined as materials combining organic and inorganic domains in a nanometric scale. The development of these organic–inorganic hybrids has achieved properties from both organic and inorganic materials. In this research we have studied the scratch behaviour of coatings of organic–inorganic hybrid materials prepared by sol–gel processing, using as precursors, trialkoxysilanes with organic functionalities that react via free radical polymerization. We have also evaluated the influence of pure inorganic precursor as tetralkoxysilanes or pure organic precursors on the scratch behaviour. The main goal of this research was to evaluate how the chemical structure of the organic–inorganic hybrid influences the scratch behaviour of the coatings.

Soft magnetic materials with an excellent performance are desired for functional applications. We present an innovative method for manufacturing the soft magnetic composites that may pave the way for magnetic cores with improved electromagnetic properties. In this paper, soft magnetic composites based on FeSi powder coated with the hybrid organic-inorganic coating composed of boron phenol-formaldehyde resin and Ni0.3Zn0.7Fe2O4 ferrite fibres were fabricated to investigate the effects of ferrite nanofibres on the structural and electromagnetic properties. A uniformity of hybrid organic-inorganic coating is reflected in a high value of the electrical resistivity. A low porosity and extraordinary high values of mechanical hardness and flexural strength were found in prepared soft magnetic composites.

Flower-like organic materials have been used for applications in supercapacitors, catalysis, corrosion science, but no report of “flower” from metal-organic compounds on porous inorganic surface has been available. Here, we report the successful fabrication of flowerlike organic-inorganic materials via the combination of TiO2-MgO film prepared on magnesium alloy through plasma electrolytic oxidation (PEO) as inorganic components and metal-quinoline, Na-8-hydroxyquinoline-5-sulfonic acid (NaHQS) and Co(II)-8-hydroxyquinoline-5-sulfonic acid (CoHQS), as the organic component. Interaction between the CoHQS complex and the porous inorganic materials then leads to the formation of flowerlike organic-inorganic coating on the magnesium surface. Furthermore, a detailed analysis of surface morphologies indicates that MHQS molecules are linked together via kinds of intermolecular hydrogen bonds and non-covalent π-π bonds between heterocyclic molecules. PEO-TiO2-CoHQS and PEO-TiO2-NaHQS exhibit enhanced electrochemical performance and chemical stability compared with the free MHQS, which was discussed based on polarization and impedance interpretation. This is attributed to the physical and chemical adsorption on the coating surface as well as the high surface area of the CoHQS in the nanoflowers.

The combination of clay and intumescent, also termed hybrid organic−inorganic coating is an attractive strategy to improve the flame retardancy of polyurethane foam (PUF). However, the fabrication of such flame retardants remains challenging as it requires the deposition of many layers to achieve the desired level of the intumescing effect. Herein, we describe a facile route to fabricate a hybrid clay−intumescent coating comprising a OnePot−deposited chitosan (CH)−phytic acid (PA) polyelectrolyte complex (PEC) intumescent stacked on top of a layer-by−layer self−assembled clay trilayer (TL) of poly− d −lysine, CH, and alginate-stabilized montmorillonite. Combustibility tests using cone calorimetry revealed that a PUF coating of CH−PA PEC intumescent on a 5 TL clay nanobrick wall (CH−PA@5 TL@PUF) can reduce the peak heat release rate (a critical flammability metric), peak rate of smoke release, and peak CO2 production rate of neat PUF by 73%, 33%, and 65%, respectively. Additionally, this hybrid coating imparted UL−94 horizontal burning rating by avoiding melt dripping and flashover, while the neat foam was completely consumed during the UL−94 flammabilty test. The proposed method is adaptable for the facile construction of other multifunctional surfaces in various application fields.

Surface chemistry is a significant field of research, especially for the preparation of organic-inorganic hybrid materials in which nearly every atom is anchored at the interface. Herein we report on the functional binding agents (FBAs), Mg(OH)2 or Co(OH)2-Mg(OH)2-Co(OH)(NO3), as efficient tools for functionalising surfaces, whereby the morphology and growth of the organic-inorganic coating can be varied by varying the interfacial composition to achieve improved functionality. To demonstrate the potential of this strategy, we combine plasma electrolytic oxidation (PEO) and a two-step dip chemical coating (DCC) technique to deliver multi-layered constructions of several chemical compositions comprising inorganic and organic components. A novel single layer of FBAs is fabricated on the rough inorganic coating through chemical treatment via DCC, transforming it into a binding site for primary clusters of 2-mercaptobenzimidazole (MBI) molecules. Thus, FBAs form coordination complexes with organic molecules, which grow on FBA surfaces. Finally, electrochemical measurements reveal that the self-assembly of organic-inorganic hybrid heterostructures appreciably suppresses metal oxidation and oxygen reduction, due to a synergistic effect arising from the combination of FBAs with organic and inorganic coatings.

Statement of Problem: Despite the numerous positive features of acrylic denture base, there are a number of undeniable associated disadvantages. The properties of denture base have been improved through various interventions including application of different types of filler and coatings. Objectives: This study aimed to evaluate the surface roughness, thickness and coating quality of organic-inorganic coating on the denture base through scanning electron microscopy. Moreover, the colour change was evaluated visually. Materials and Methods: The organic-inorganic hybrid coatings were prepared. Acrylic discs of 10×10 mm were fabricated. The test discs were dipped in the hybrid coating and cured. In order to evaluate the surface roughness and coating thickness, the surface and cross-section of the samples in both coated and control groups were subjected to scanning electron microscopy. The colour change and transparency were visually evaluated with naked eyes. The data were statistically analyzed by student’s t test. Results: The hybrid materials perfectly covered all the surfaces of acrylic resin and established proper thickness. The coated group seemed smoother and flatter than the control group; however, the difference was not statistically significant ( for all parameters p > 0.05). It was quite a thin coating and no perceptible colour change was observed. Conclusions: The hybrid coating maintained good binding, caused no noticeable discoloration, and thoroughly covered the acrylic resin surface with uniform delicate thickness. It also slightly improved the acrylic resin surface roughness.

The analysis of methods of determining the intumescent ability of fire­retardant coatings was performed, and the need to develop reliable methods for the study of the blistering process for the creation of new types of coatings was identified. Evaluation of the swelling ratio of inorganic and organic coatings, revealed the unreliability of the real values of the kinetics of decomposition of materials. The method for determining the kinetics of swelling of coatings was validated, and with the constant heat and mass transfer conditions during the test, the device was designed. Studies of the kinetics of swelling of organic­inorganic coatings by this method have shown that under prolonged exposure to high temperature, the swelling coefficient decreases due to the foam­coke burnout. The results of determining the intumescent ability of coatings when adding fillers showed that when exposed to high­temperature stream, the material burnout and the coating weight loss are reduced by more than half due to the formation of high­temperature compounds, and this increases the time to reach the limit temperature. As a result of thermogravimetric study, the weight loss of the coatings depending on the temperature was determined, the activation energy was investigated in the temperature expansion of the coatings and it was found that for organic­inorganic coating, it was 18.79 kJ/mol, and in the case of the introduction of fillers – tripled. These data suggest the feasibility of the use of fillers based on oxides and hydroxides to improve the efficiency of organic­inorganic coatings.

Neodymium–iron–boron magnets are able to ensure a magnetic flux with high maximum energy product also at miniaturized size. In the past, due to their marked corrosion in saliva they were unsuccessfully implemented in orthodontic systems. Thereby, we propose a multi-layered organic–inorganic coating able to supply anticorrosion resistance, wear resistance and durability to the whole assembly. We evaluated the influence on the magnetic force of commercial nickel plated and silanized Nd–Fe–B during aging time in synthetic Fusayama saliva. Two magnets based-micromagnetic simulations were performed in order to analyze the magnetic field generated which is linked to the magnetic force. Our key results underline that the proposed hybrid coating does not affect the magnetic force of Nd–Fe–B magnets, moreover, preventing corrosion degradation in aggressive solution. Thus the limiting aspects avoiding the use of Nd–Fe–B magnets for orthodontic and prosthodontic applications can be overcome by using silane agents as surface coating.

Surface properties like hydrophobicity and morphology of the substrate are essential for cell proliferation affecting its growth, survival and also for its communication with other cells on fabrics. The combination of low surface energy and a specific surface morphology (micro/nano-roughness) leads to significantly less wettable surfaces, known as superhydrophobic characterized by high contact angle above 150 degrees and a very small hysteresis. Such high water repellent coatings feature small area available to be exploited in many applications where interactions with aqueous environment are strongly to be avoided. In this work, the authors have investigated the influence of coating polyester fabric at different degree of hydrophobicity by mixed organic inorganic coating with moderated to highly water repellence. Depending on the coating composition and structure, the hydrophobicity of the fabric can be finely modulated by an easy-to-prepare method applicable to commercial, low cost fabric substrates providing advanced performance. In vitro experiments have been performed in order to establish the influence of surface modification on adhesion of representative model mammalian cell lines such as 3T3 fibroblasts, HaCaT keratinocytes and HeLa epithelial carcinoma cells. The obtained results suggested that, in addition to the chemistry and morphology of the coating, the characteristics of the substrate are important parameters on the final cell viabilities.

In the present study, the synergistic effect on the corrosion protection properties of Mg alloys subjected to plasma electrolytic oxidation and chemically treated with thiourea as an inhibitor is investigated by surface microstructure analysis, evaluation of the electrochemical performance, and chemical quantum calculations. Physical adsorption of thiourea on the inorganic material surface might be due to physical interaction between thiourea with a low ionization potential serving as an electron donor and the inorganic components with high electron affinities acting as acceptors. The results from potentiodynamic polarization and electrochemical impedance spectroscopy for organic-inorganic coating reveal a clear decrease in the corrosion rate owing to the introduced thiourea.

The protection of stainless-steel implants by applying a hybrid organic–inorganic coating generates a barrier for ion migration and a potential holder for functional particles. Chemical composition of bioactive silicate-glasses (BG) can be varied to tailor their rate of dissolution in the biological environment. The substitution of calcium by strontium (Sr) generates a locally-controlled release of Sr-ions to the media. Strontium is known to reduce bone resorption and stimulate bone formation. This work presents coatings made by sol–gel method containing tetraethoxysilane, methyl-triethoxysilane and silica nanoparticles as precursors, and functionalized either with BG or Sr-substituted BG particles onto surgical grade stainless steel. The coated implants were tested in vitro for corrosion resistance and bioactivity, and in vivo to analyze bone formation. The applied coating system provided an excellent protection to aggressive fluids, even after 30 days of immersion. The presence of hydroxyapatite is shown as a first evidence of bioactivity. The evaluation of in vivo tests in Wistar–Hokkaido rat femur 4 or 8 weeks after the implantation showed slight differences in the thickness of newly formed bone measured by ESEM, and remarkable changes in bone quality characterized with Raman microscopy. The in vivo response of the coatings containing Sr-substituted bioglass is better at early times of implantation as regards the bone morphology and quality making this functionalized coatings a very promising option for implant protection and bone regeneration. Fil: Omar, Sheila Ayelén. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentina Fil: Repp, Felix. Institut Max Planck fuer Bioanorganische Chemie; Alemania Fil: Desimone, Paula Mariela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentina Fil: Weinkamer, Richard. Institut Max Planck fuer Bioanorganische Chemie; Alemania Fil: Wagermaier, Wolfgang. Institut Max Planck fuer Bioanorganische Chemie; Alemania Fil: Ceré, Silvia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentina Fil: Ballarre, Josefina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentina

Purpose – The purpose of this paper was to prepare a hybrid organic/inorganic coating with interesting barrier properties against the corrosion of plain carbon steel sheets in 3.5 per cent NaCl solution. The search for replacing chromates in protective coatings has led to the development of hybrid sol-gel anticorrosive coatings. Appropriate functionalization can dramatically enhance the chemical durability and mechanical strength of these coatings. Design/methodology/approach – To prepare the targeted coating, 1,2-epoxybutane (EB) was mixed with 2 to 4 per cent aminoethylaminopropyl-methylsiloxane dimethylsiloxane (APDMS) copolymer and 1,6-diaminohexane. The above coating (EBAC) has been further mixed with three different corrosion inhibitors “Moly-white® 101-ED, Heucophos Zapp® and cerium ammonium nitrate”, yielding the coatings EBAC-M, EBAC-Z and EBAC-Ce, respectively. The corrosion characteristics of all coatings on the steel panels immersed in 3.5 per cent NaCl solution were obtained using different electrochemical methods such as electrochemical impedance spectroscopic and Tafel polarization measurements. Findings – The newly prepared coatings showed interesting protection properties for protecting the steel substrate against corrosion in chloride-containing media. Originality/value – The results provide a good approach for the modification of polydimethylsiloxane coatings using a simple organic modifier.

Purpose – The purpose of this work was to prepare a hybrid organic/inorganic coating with interesting barrier properties against the corrosion of plain carbon steel sheets in 3.5 per cent NaCl solution. The search for replacing chromates in protective coatings has led to the development of hybrid sol-gel anticorrosive coatings. Appropriate functionalization can dramatically enhance the chemical durability and mechanical strength of these coatings. Design/methodology/approach – To prepare the targeted coating, 1,2-epoxybutane (EB) was mixed with 2-4 per cent aminoethylaminopropyl-methylsiloxane dimethylsiloxane copolymer and 1,6-diaminohexane. The above coating (EBAC) was further mixed with three different corrosion inhibitors “Moly-white® 101-ED, Hfucophos Zapp®” and Cerium Ammonium Nitrate, yielding the coatings (EBAC-M), (EBAC-Z) and (EABC-Ce), respectively. The corrosion characteristics of all coatings on carbon steel panels immersed in 3.5 per cent NaCl solution were obtained using different electrochemical methods such as electrochemical impedance spectroscopic and Tafel polarization measurements. Findings – The newly prepared coatings showed interesting properties for protecting the steel substrate against corrosion in chloride containing media. Originality/value – The results provide a good approach for the modification of polydimethylsiloxane coatings using a simple organic modifier.

Organic-inorganic SiO2-TiO2 sol-gel coatings were prepared and applied on a mild steel substrate using dip coating technique and subsequently heat treated at 200 and 300 °C to improve the corrosion resistance. The coating sols were synthesized using Glycidoxytrimethoxysilane and titanium tetraisopropoxide as precursor materials. The corrosion resistances of the both coated and uncoated samples were evaluated by the Tafel polarization and electrochemical impedance spectroscopy in NaCl solution. The microstructure of coated specimens was characterized by scanning electron microscopy. Fourier transformed infrared and energy dispersive spectroscopy analyses were used to identify the presence of various functional groups in the coating solutions. A comparison of the corrosion resistance of the coated and uncoated mild steel was presented. i corr values of coated specimens heat treated at 200 °C were between 6.9 and 9.2 times smaller than those of uncoated specimen. In the case of coated specimens heat treated at 300 °C, i corr values were 4.4 and 5 times smaller than those of uncoated specimen. The coating film was noted to be smooth and between 7.2- and 7.5-µm thick. The measured electrochemical parameters indicated that the corrosion resistance was improved by the coating film. The elasticity of the coating can be improved by the presence of organic groups in the coating which reduces stress and crack formations during sintering. Ultimately, crack-free and elastic coating was obtained by heat treating of organic-inorganic coating at as low as 200 °C.

Plasma polymerisation of an organophosphorus monomer in atmospheric pressure-dielectric barrier discharge was studied. Phosphate-based molecules were introduced as a vapour into a nitrogen plasma at atmospheric pressure and a phosphorus-containing coating was obtained. Scanning electron microscopy and ellipsometry revealed the morphology of the coating while Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy indicated a hybrid organic–inorganic coating containing phosphate, organophosphate and different N-containing groups. The new polymer structure of the coating was highlighted by secondary ion mass spectrometry.

PurposeThe purpose of this paper is to focus on the corrosion protection of magnesium alloy ZK10 by applying via the dip‐coating process an hybrid organic‐inorganic coating that contains nanocontainers of TiO2 loaded with corrosion inhibitor.Design/methodology/approachThe coating consists of cross‐linked polymers containing epoxy groups, conductive polymer polypyrrole as well as organic modified silicates. The morphology and the composition of the coating were examined with scanning electron microscopy and energy dispersive X‐ray analysis, respectively.FindingsCorrosion tests via electrochemical impedance spectroscopy denoted that the incorporation of loaded nanocontainers improved the anticorrosion properties of the coating by increasing the impedance values in the low frequency range. Moreover, the surface of the aforementioned coating remained crack free after the exposure of the sample to corrosive environment.Originality/valueThe paper presents a new system which has been developed for the corrosion protection of magnesium alloy ZK10.

This study is focused on corrosion protection of magnesium alloy ZK10. The aim of the research was the production of a hybrid organic–inorganic coating that would be a combination of epoxy resin, organically modified silicates as well as conductive polymer. Furthermore, ceramic containers loaded with corrosion inhibitor were incorporated into the coating for the improvement of its corrosion protection properties. The composition and structure of the coatings were investigated by Fourier transform infrared spectroscopy, energy dispersive X-ray analysis and scanning electron microscopy. Extent of the anti-corrosion protection of the formed coatings was examined electrochemically using electrochemical impedance spectroscopy. The results showed that the incorporation of the containers loaded with inhibitor into the coatings improved their corrosion protection properties. Furthermore, artificial defects of 1 mm were made to the coatings with the best anticorrosive performance in order to study the electrochemical processes taking place in the scratched area and to estimate the effect of the corrosion inhibitor in the corrosion of the substrate.

The work presented in this paper focuses on the synthesis and characterization of a hybrid organic/inorganic chemically sensitive layer for rapid detection and analysis of OPs in aqueous solutions using SH-SAW devices. Coated SH-SAW devices on 36° YX-LiTaO and 42.75° YX-Quartz (ST-90° X Quartz), are used to determine the optimum operating conditions for achieving rapid sensor responses with high sensitivity. Three analytes (parathion-methyl, parathion, and paraoxon), having similar molecular mass and volume, are used to evaluate the performance of the hybrid organic/inorganic coating in terms of sensor properties of interest including sensitivity, selectivity, reproducibility. It is shown that the coating has a high degree of partial selectivity and sensitivity towards the analytes. With the present non-optimized chemical sensor, a limit of detection of 60 (ppb), 20 (ppb) and 100 (ppb) is estimated for parathion-methyl, parathion, and paraoxon, respectively, when using a 0.5 -thick BPA-HMTS sensing layer. Concentrations as low as 500 (ppb) parathion have been measured. This concentration is significantly much lower than the typical concentrations found on agricultural produce (≥10 ppm).

Cotton fabrics were treated with a hybrid organic–inorganic coating obtained through a dual-cure process, i.e. a photopolymerization reaction followed by a thermal treatment for promoting the formation of silica phases through a sol–gel process. To this aim, different amounts of a silica precursor were added to an acrylic UV-curable formulation in the presence of a suitable coupling agent. The thermo-mechanical properties of the treated fabrics were investigated and correlated to the composition and morphology of the hybrid organic–inorganic system. Furthermore, their flame retardancy and combustion behavior were evaluated by flammability tests and cone calorimetry and compared with the performances of pure cotton.

Dielectromagnetics made from organic–inorganic hybrid silica-coated iron powders were characterised by determination of their physical, mechanical and magnetic properties. The influence of three main factors, dielectric composition, addition level and heat treatment conditions were investigated. Results showed that these factors have significant effects on the performance of the dielectromagnetics. Increase in the organic phase content in these dielectric coatings tends to increase both the electrical resistivity and magnetic permeability of dielectromagnetics, although the strength and density are slightly impaired. Increasing the coating thickness leads to improvements in resistivity and thus reduced eddy current losses, but these are offset by reductions in density, strength and particularly magnetic permeability. A hybrid organic–inorganic coating formulation based on 40 mol% MTMS and 60 mol% TEOS precursors was found to be the optimum composition investigated. Addition levels between 0.1% and 0.3% were found to offer a good compromise between maximum permeability ( μ max >400) and minimum loss (typically

The increasing relevance of active electronic implants for medical surgery and the progress in encapsulation technology open up a new field of applications for high quality coatings in order to remove expensive and damageable ceramic housings. This article intends to show a possible way to create an organic-inorganic coating system based on a highly filled polymer film in combination with an inorganic barrier layer.

We propose a novel composite organic-inorganic coating in the form of a redox polymer film for protection of stainless steel against general corrosion in strong acid medium (2 M H2SO4). We utilize an anion exchange polymer, protonated poly(4-vinylpyridine), into which hexacyanoferrate anions have been introduced. Owing to the presence of Fe(CN)6 3−/4− at the interface formed by the film and the steel, a sparingly soluble metal hexacyanoferrate (mostly Prussian blue, PB) is formed as an overcoating on the steel’s surface, presumably on the passive (metal oxide) layer. The redox polymer film on the steel seems to act as a composite three-dimensional bilayer-type coating in which hexacyanoferrate(III,II) anions (that are capable of effective charge storage) exist in the outer portions of the film, whereas the inner PB layer improves the system’s overall adherence and stability. By analogy to a conducting polymer (e.g. polyaniline, polypyrrole), introduction of the redox polymer composite film leads to stabilization of the steel substrate’s potential within the passive range.

A comprehensive investigation of the morphological and interfacial changes of Mn3O4 particles at different lithiation stages was performed in order to improve our understanding of the mechanism of the irreversible conversion reaction of Mn3O4. The micronization of Mn3O4 into a Mn-Li2O nanocomposite microstructure and the formation of a solid electrolyte interphase (SEI) on the Mn3O4 surface were carefully observed and characterized by combining high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), and in situ X-ray absorption fine structure (XAFS) measurements. Accumulation of a thin SEI film of 2-5 nm thickness on the surfaces of the Mn3O4 particles due to their catalytic decomposition was observed at a depth of discharge (DOD) of 0%. As the DOD increases from 25% to 75%, the SEI layer composed of Li2CO3 and LiF continues to grow to 20-30 nm, and Li2O nanoparticles are clearly observed. At 100% DOD, the Mn-Li2O particles with diameters of 2-5 nm become totally encapsulated within a huge organic-inorganic coating structure, while the overall starting shape of the particles remains.

Results on the subcritical crack growth in a hybrid organic–inorganic coating are reported. The crack growth rate appeared to depend on the crack length and the coating thickness. The crack growth rate is related to the energy release rate and a tentative explanation of the fracture behavior is proposed.