Preparation of fluorine containing hybrid coatings: investigation of coating performance onto ABS and PMMA substrates

UV‐curable fluorinated organic–inorganic hybrid coatings were prepared by the sol–gel technique. Perfluorinated urethane modified alkoxysilane was synthesized by the reaction between perfluoro alcohol and 3‐isocyanatopropyltrimethoxysilane. The prepared formulations were applied onto poly(methyl methacrylate) (PMMA) and acrylonitrile butadiene styrene (ABS) panels and polymerized by UV‐curing. The properties of the hybrid coatings such as hardness, chemical resistance, thermal stability, surface morphology, double bond conversion, and also contact angle measurements were investigated. Contact angle measurements have shown that the addition of fluorinated silane precursor to the hybrid system improved the water repellency and increased the contact angle from 65° to 106°. Copyright © 2009 John Wiley & Sons, Ltd.     

UV and thermally stable polystyrene‐MWCNT superhydrophobic coatings

A facile method for ultraviolet (UV) and thermally stable polystyrene‐multiwalled carbon nanotubes (PS‐MWCNT) superhydrophobic coatings was demonstrated by a simple spray coating method. The superhydrophobicity was understood by an increase in micro/nano roughness with the addition of MWCNTs. Surface morphology of the coatings showed protrusion like structure. The wetting behavior of the coatings was studied as a function of temperature, and it is observed that the coatings were superhydrophobically stable up to 250 °C. A transformation of superhydrophobic to superhydrophilic state is achieved at 300 °C. The coatings remained superhydrophobically stable when it was subjected to UV‐irradiation and water immersion of 50 h. Thermogravimetric analysis showed a small shift (10°) towards higher temperature region with an addition of MWCNTs, suggesting the presence of weak interactions between PS and MWCNT, which is also supported by Fourier transform infrared spectroscopy, Raman and X‐ray photoelectron spectroscopy studies. Both hydrophilic and superhydrophobic coatings find potential applications in our daily life. Copyright © 2016 John Wiley & Sons, Ltd.     

The maleimide modified epoxy resins for the preparation of UV‐curable hybrid coatings

In the present study, maleimide‐modified epoxide resin containing UV‐curable hybrid coating materials were prepared and coated on polycarbonate substrates in order to improve their surface properties. UV‐curable, bismaleimide‐modified aliphatic epoxy resin was prepared from N‐(p‐carboxyphenyl) maleimide (p‐CPMI) and cycloaliphatic epoxy (Cyracure‐6107) resin. The structure of the bismaleimide modified aliphatic epoxy resin was analyzed by FTIR and the characteristic absorption band for maleimide ring was clearly observed at 3100 cm^?1. Silica sol was prepared from tetraethylorthosilicate (TEOS) and methacryloxy propyl trimethoxysilane (MAPTMS) by sol–gel method. The coating formulations with different compositions were prepared from UV‐curable bismaleimide‐based epoxy oligomer and sol–gel mixture. The molecular structure of the hybrid coating material was analyzed by ²⁹Si‐CP/MAS NMR spectroscopy techniques. In the ²⁹Si CP/MAS NMR spectrum of the hybrid coating, mainly two kinds of signals were observed at ?68 and ?110 ppm that correspond to T³ and Q⁴ peaks, respectively. This result shows that a fully condensed structure was obtained. The thermal and morphological properties of these coatings materials were investigated by using TGA and SEM techniques. Hardness and abrasion resistance properties of coating materials were examined and both were found to increase with sol–gel precursor content of the coating. The photopolymerization kinetics was investigated by using RT‐IR. 70% conversion was attained with the addition of 15 wt% of BMI resin into the acrylate‐based coating formulation. It was found that the UV‐curable organic–inorganic hybrid coatings improved the surface properties of polycarbonate. Copyright © 2009 John Wiley & Sons, Ltd.     

Preparation and properties of Ni–Co–P/nano‐sized Si3N4 electroless composite coatings

Ni–Co–P/nano‐sized Si₃N₄ composite coating was successfully fabricated on aluminum alloys by electroless plating in this work. The surface and cross‐sectional morphologies, composition, microstructure, microhardness, friction and wear behavior of deposits were investigated with SEM, EDS, XRD, Vickers hardness and high‐speed reciprocating friction, respectively. It was found that a Ni–Co–P/nano‐sized Si₃N₄ composite coating on aluminum alloy substrate is uniform and compact. The existence of nano‐sized Si₃N₄ particles in the Ni–Co–P alloy matrix causes a rougher surface with a granular appearance, and increases the microhardness but decreases the friction coefficients and wear rate of electroless coatings. Meanwhile, the effects of heat treatment at 200, 300, 400 and 500 °C for 1 h on the hardness and tribological properties were researched. It is revealed that both of the microhardness and tribological properties of Ni–Co–P coatings and Ni–Co–P/Si₃N₄ composite coatings increase with the increase of heating temperature in the range of 200–400 °C, but show different behavior for the two coatings after annealing at 500 °C. Copyright © 2011 John Wiley & Sons, Ltd.     

Functional properties of microwave‐absorbent nanocomposite coatings based on thermoplastic polyurethane‐based and hybrid carbon‐based nanofillers

This paper describes the effect of nanofillers, such as nanographite, nickel–zinc ferrite (NiZnFerrite), and in‐house developed hybrid nanographite particles (i.e. iron‐coated nanographite [FeNG] and iron–nickel co‐deposited nanographite [FeNiNG] particles), on microwave‐absorption properties of thermoplastic polyurethane (TPU) based nanocomposite coatings on textile substrate. The flexible coatings were tested for various functional properties such as microwave absorbency, gas barrier property, impedance, and weather resistance. The comparison has also been made with other fillers such as bulk graphite (G) and iron powder (Fe) and carbon nanofiber (CNF) in coating form. The nanoparticles' dispersion was observed through optical microscope and phase image analysis on atomic force microscopy. The impedance behavior of such coated samples with 10 wt% nanofillers is frequency dependent except for CNF, which shows frequency‐independent behavior even at 2 wt% loading. The gas barrier property of the FeNG‐based and FeNiNG‐based coatings is better than that of pure TPU; however, G‐based, NG‐based, and NiZnFerrite‐based coatings show excellent barrier property. The coatings were evaluated for their microwave absorbency at low‐frequency (from 0.3 to 1.5 GHz) as well as high‐frequency (8–18 GHz) ranges. The FeNG‐based and FeNiNG‐based nanocomposite coatings showed good absorbency over a frequency range of 8 to 14 GHz as compared with those of others. The flexibility of the nanocomposite films is almost retained even at 10 wt% nanofiller loading. The weather resistance of the films was also evaluated, and the FeNiNG‐based coating outperformed the FeNG‐based coating as the latter is prone to oxidation on exposure to environment. Copyright © 2011 John Wiley & Sons, Ltd.     

UV curing of organic–inorganic hybrid coating materials

The effect of UV-curing time on the mechanism of interaction between the various precursor phases in a novel sol–gel-derived organic–inorganic hybrid coating material and the resulting mechanical and thermal properties of this material when coated onto substrates in thin film form have been examined using a variety of chemical and physical characterisation methods. Microstructurally, the hybrid coating materials examined were all a single amorphous phase and were all optically transparent. The degree of interaction between the organic and inorganic phases, the scratch behaviour of the coating materials and the thermal stability of the coating materials were all found to depend strongly on the UV curing time. For the particular proportions of inorganic and organic components used to make up this hybrid coating material, an optimum UV curing time of 10 min under a UV intensity of 46.3 mW cm⁻² was found to produce transparent coatings which adhered well to the substrates and which were robust in scratch tests on aluminium and polycarbonate substrates and abrasion tests on polycarbonate substrates.     

Polysilazane as the source of silica: the formation of dense silica coatings at room temperature and the new route to organic–inorganic hybrids

Xylene solutions of perhydropolysilazane (PHPS) were used as the coating solutions for preparing silica coatings at room temperature. The PHPS-to-silica conversion was achieved by exposing the spin-on coatings to the vapor from aqueous ammonia. In order to examine the significance of the mechanical properties of the PHPS-derived silica coatings, the pencil hardness was measured, which was compared with that of tetraethoxysilane (TEOS)-derived silica coatings. The pencil hardness was over 9H at a load of 1 kg, which was much higher than that of the TEOS-derived silica gel films, and was comparable to that of the TEOS-derived films heat treated at 300 °C. Second, poly(methyl methacrylate) (PMMA)–silica hybrid coatings were prepared from xylene solutions of PMMA and PHPS via exposure to the vapor from aqueous ammonia. Crack-free, optically transparent PMMA–silica hybrid coatings could be prepared, where PHPS-to-silica conversion was confirmed by infrared absorption spectroscopy. The refractive index was around 1.42–1.50, and the contact angle with water increased from 35 to 70° with increasing PMMA content. The pencil hardness greatly increased during the PHPS-to-silica conversion, and was much higher than that of the non-heat treated TEOS-derived hybrid coatings. The durability in tetrahydrofuran (THF) was also evaluated by measuring the reduction in thickness occurring during soaking in THF. The durability decreased with increasing PMMA content, but was much higher than that of the non-heat treated TEOS-derived hybrid coatings. Both the hardness and the durability were comparable to those of the TEOS-derived coatings heated at 300 °C. The hybrid coatings could also be deposited on poly(ethylene terephthalate) substrates, where no cracks were observed at high PMMA contents even when the substrate was bent.     

New approach to fabricate an extremely super‐amphiphobic surface based on fluorinated silica nanoparticles

Superoleophobic surfaces possessing static contact angles greater than 140° with organic liquids are extremely rare. A simple approach has been developed to fabricate an extremely superamphiphobic coating material based on fluorinated silica nanoparticles resulting contact angles of water and diiodomethane at 167.5° and 158.6°, respectively. The contact angle of diiodomethane at 158.6° is substantially higher than the highest literature reported value we know of at 110°. In addition, this developed film also possesses extremely high contact angles with other organic liquids such as soybean oil (146.6°), decahysronaphthalene (142.5°), diesel fuel (140.4°), and xylene (140.5°). This developed superamphiphobic organic–inorganic hybrid film possesses unique liquid repellency for both water and organic liquids that can be used as functional coatings on numerous substrates by a simple coating process. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 1984–1990, 2008     

Inhibition effect of cerium in hybrid sol–gel films on aluminium alloy AA2024

Aluminium alloys such as AA2024 are susceptible to severe corrosion attack in aggressive solutions (e.g. chlorides). Conversion coatings, like chromate, or rare earth conversion coatings are usually applied in order to improve corrosion behaviour of aluminium alloys. Methacrylate‐based hybrid films deposited with sol–gel technique might be an alternative to conversion coatings. Barrier properties, paint adhesion and possibly self‐healing ability are important aspects for replacement of chromate‐based pre‐treatments. This work evaluates the behaviour of cerium as corrosion inhibitor in methacrylate silane‐based hybrid films containing SiO₂ nano‐particles on AA2024. Hybrid films were deposited on aluminium alloy AA2024 by means of dip‐coating technique. Two different types of coating were applied: a non‐inhibited film consisting of two layers (non‐inhibited system) and a similar film doped with cerium nitrate in an intermediate layer (inhibited system). The film thickness was 5 µm for the non‐inhibited system and 8 µm for the inhibited system. Film morphology and composition were investigated by means of GDOES (glow discharge optical emission spectroscopy). Moreover, GDOES qualitative composition profiles were recorded in order to investigate Ce content in the hybrid films as a function of immersion time in 0.05 M NaCl solution. The electrochemical behaviour of the hybrid films was studied in the same electrolyte by means of EIS technique (electrochemical impedance spectroscopy). Electrochemical measurements provide evidence that the inhibited system containing cerium displays recovery of electrochemical properties. This behaviour is not observed for the non‐inhibited coating. GDOES measurements provide evidence that the behaviour of inhibited system can be related to migration of Ce species to the substrate/coating interface. Copyright © 2010 John Wiley & Sons, Ltd.     

Electrochemical impedance spectroscopy and in situ UV‐vis spectroelectrochemistry studies of Poly(N‐vinyl carbazole)/ Polydimethylsiloxane composite electrodes

Poly(N‐vinyl carbazole)/polydimethylsiloxane (PNVCz/PDMS) composite electrodes were prepared by electrochemical polymerization of NVCz monomer onto PDMS‐coated platinum (Pt) and glassy carbon (GC) electrode surfaces to investigate the influence of the insulating constituent, PDMS and process temperature on the capacitive performance of the coated layers. The electrochemical properties of the bilayer coatings were studied by electrochemical impedance spectroscopy and UV‐vis spectroelectrochemistry measurements. The low‐frequencies capacitance values of composite electrodes indicated that the capacitive behaviors of the composites decreased with increasing PDMS content (from 5.0 to 10.0; in wt/v%) in coating solutions at 25 °C, and with decreasing coating temperatures (from 25 °C to ? 15 °C) of PDMS and PNVCz and, more resist PDMS/PNVCz layers formed. Copyright © 2011 John Wiley & Sons, Ltd.     

Renewable epoxidized cardanol‐based acrylate as a reactive diluent for UV‐curable resins

A novel kind of biobased monomer, epoxidized cardanol‐based acrylate (ECA), was successfully synthesized from cardanol via acrylation and epoxidization. The chemical structure was confirmed by Fourier transform infrared spectroscopy and proton nuclear magnetic resonance. Then, the ECA was employed to produce UV‐curable films and coatings copolymerized with castor oil‐based polyurethane acrylate. Compared to coatings from petroleum‐based diluent hydroxyethyl acrylate‐based castor oil‐based polyurethane acrylate resins, ECA‐based biomaterials exhibited a little inferior dilution ability but overcome the drawback of high volumetric shrinkage with a special lower value. Moreover, ultimate properties of the UV‐cured biomaterials such as thermal, mechanical, coating, swelling, and hydrophobic properties were investigated. The UV‐curing behavior was investigated using real‐time IR, and the overall double bond conversion was more than 90%. This biobased UV‐curable cardanol‐based diluent shows a promise in “green + green” materials technologies.     

Synthesis and characterization of UV‐curable phosphorus containing hybrid materials prepared by sol–gel technique

In this study, a series of ultraviolet (UV)‐curable organic–inorganic hybrid coating materials containing phosphorus were prepared by sol–gel approach from acrylate end‐capped urethane resin, acrylated phenyl phosphine oxide oligomer (APPO), and inorganic precursors. TEOS and MAPTMS were used to obtain the silica network and Ti:acac complex was employed for the formation of the titania network in the hybrid coating systems. Coating performance of the hybrid coating materials applied on aluminum substrates was determined by the analysis techniques, such as hardness, gloss, impact strength, cross‐cut adhesion, taber abrasion resistance, which were accepted by international organization. Also, stress–strain test of the hybrids was carried out on the free films. These measurements showed that all the properties of the hybrids were enhanced effectively by gradual increase in sol–gel precursors and APPO oligomer content. The thermal behavior of the hybrid coatings was investigated by thermogravimetric analysis (TGA) analysis. The flame retardancy of the hybrid materials was examined by the limiting oxygen index (LOI); the LOI values of pure organic coating (BF) increased from 31 to 44 for the hybrid materials containing phosphorus (BF‐P:40/Si:10). The data from thermal analysis and LOI showed that the hybrid coating materials containing phosphorus have higher thermal stability and flame resistance properties than the organic polymer. Besides that, it was found that the double bond conversion values for the hybrid mixtures were adequate in order to form an organic matrix. The polycondensation reactions of TEOS and MAPTMS compounds were also investigated by ²⁹Si‐NMR spectroscopy. SEM studies of the hybrid coatings showed that silica/titania particles were homogenously dispersed through the organic matrix. In addition, it was determined that the hybrid material containing phosphorus and silica showed fibrillar structure. Copyright © 2009 John Wiley & Sons, Ltd.     

Effects of hydrophobic polyhedral oligomeric silsesquioxane coating on water vapour barrier and water resistance properties of paperboard

The substitution of fossil based packaging materials with materials from renewable sources is a topic of current interest. Polyhedral oligomeric silsesquioxanes with fatty acid moieties can have a renewable content of more than 90 % and are therefore called bio-POSS. In this study the bio-POSS octa-(ethyl erucamide) silsesquioxane was coated on a paperboard substrate as a liquid coating. The water resistance and the water vapour barrier properties of the paperboard were improved. Samples on which the bio-POSS coating layer was dried at 80 °C had a slightly higher water resistance and water vapour barrier than samples dried at room temperature. UV treatment of the coating layer had little effect. Solid state ¹H-NMR of UV treated coatings showed no reaction of double bonds of bio-POSS in the coating layer. Multiple coating considerably enhanced the water resistance and water vapour barrier properties of the paperboard, due to an increase in the coating thickness and a reduction in number of pores on top coated surfaces.     

Simple preparation routes for corrosion protection hybrid sol‐gel coatings on AA 2024

In recent years, many hybrid inorganic‐organic systems have been proposed in order to replace the traditional conversion coatings on metals like aluminum, and some results have been promising. However, many proposed solutions are based on complicated processes which are not easy to be adapted to industrial scale. The aim of this study was to establish a simple process leading to the production of highly efficient corrosion protective hybrid sol‐gel coating systems for the aluminum alloys as replacement for the highly hazardous conventional chromate conversion coatings. Hybrid coatings have been realized by means of the sol‐gel process. CeO₂ and ZnO have been introduced as dispersions of nanoparticles in the system and used as corrosion inhibitors. The aim of this work was to obtain pore‐free coatings with increased barrier properties using nanoparticles that possess the double function of pore fillers and corrosion inhibitors. The proposed processes led to coating materials with good adherence to the aluminum substrate and an extremely long life in the accelerated neutral salt spray test according to DIN ISO 9227. Electrochemical impedance spectroscopy approves these results by high impedance values in the low‐frequency region of the Bode plot. Copyright © 2011 John Wiley & Sons, Ltd.     

Photocatalytic TiO2 coatings on limestone

The application of photocatalytic coatings on stone has been investigated for providing surface protection and self-cleaning properties. Sol–Gel and hydrothermal processes were used to synthesise TiO₂ colloidal suspensions and coatings with enhanced photocatalytic activity without any thermal curing of the coated stone. The stone was a porous limestone (apulian sedimentary carbonatic, calcite stone). Films and powders prepared from TiO₂ sols were studied using X-ray diffraction to evaluate the microstructure and identify rutile and anatase phases. A morphological and physical characterisation was carried out on coated and uncoated stone to establish the changes of appearance, colour, water absorption by capillarity and water vapour permeability. The photocatalytic activity of the coated surface was evaluated under UV irradiation through NO _x and organics degradation tests. The performances of the synthesised TiO₂ sols were compared with commercial TiO₂ suspension. Since the coating doesn’t need temperature treatments for activating the photocatalytic properties, the nano-crystalline hydrothermal TiO₂ sols seem good candidate for coating applications on stone that cannot be annealed after the coating application.     

Preparation and characterization of polyurethane based self-cleaning and antibacterial coating containing silver ion exchanged montmorillonite/TiO<Subscript>2</Subscript> nanocomposite

In order to reach an antibacterial, photocatalytic, and hydrophilic coating, commercial grade polyurethane (CPU) resin was modified with silver ion exchanged montmorillonite/TiO₂ nanocomposite in various montmorillonite to TiO₂ nanoparticle ratios. To characterize the prepared nanocomposites and coatings, X-ray diffraction patterns, FTIR and UV–Vis spectroscopy and SEM images were used. The modified commercial grade polyurethane coatings containing nanocomposites show better properties, including hydrophilicity, degradation of organic pollutants, antibacterial activity and water resistivity, compared to unmodified commercial grade polyurethane coatings. The water droplet contact angle of unmodified CPU coating was 70°, however it decreased to lower than 10° in modified CPU coatings after 24 h LED lamp irradiation. Decolorization efficiency of malachite green dye solution by the use of modified CPU coatings achieved up to 70% after 5 h LED lamp illumination, compared to less than 5% for unmodified CPU coatings. Modified CPU coatings also showed significant water resistivity and antibacterial properties.     

Synergistic effect of functional carbon nanotubes and graphene oxide on the anti‐corrosion performance of epoxy coating

In this work, we reported the synergistic effect of functional carbon nanotubes (CNTs) and graphene oxide (GO) on the anticorrosion performance of epoxy coating. For this purpose, the GO and CNTs were firstly modified by the 3‐aminophenoxyphthalonitrile to realize the nitrile functionalized graphene oxides (GO‐CN) and carbon nanotubes (CNTs‐CN). As modified GO‐CN and CNTs‐CN were characterized and confirmed by Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopy, and gravimetric analyzer. It was found that about 19 and 24 wt% of 3‐aminophenoxyphthalonitrile were grafted onto the surface of the GO and CNTs, respectively. The electrochemical impedance spectroscopy results showed that the GO‐CN&CNTs‐CN hybrid materials exhibit a remarkable superiority in enhancing the anticorrosion performance of epoxy coatings. Significant synergistic effect of the lamellar structural GO‐CN and CNTs‐CN on the anticorrosion performance of epoxy composite coatings was designed. Besides, the epoxy coating with 1 wt% of the GO‐CN&CNTs‐CN hybrid exhibited the best anticorrosion performance, in which the impedance showed the largest one (immersion in 3.5 wt% of NaCl solution for 168 hr). Copyright © 2016 John Wiley & Sons, Ltd.     

Elimination of a zero-growth in thickness of Al<Subscript>2</Subscript>O<Subscript>3</Subscript> protective film deposited by cycles of dip-coating method

Multilayered alumina film was deposited onto metallic substrate using cycles of dip-coating method. The film thickness was found not always growing linearly with the increase of the number of dipping cycles, and even a zero-growth in thickness was observed after 20 cycles of dip coatings. This phenomenon was found to be attributed to the dissolving behavior of alumina gel material in original sol. A heat treatment at a temperature higher than 230 °C was found to be able to effectively lower the dissolvability of Al₂O₃ gel material, but an extra high temperature, i.e., 600 °C led to the formation of cracks in the multilayered film due to the increase of interfacial tension force. It was examined by IR and XRD analyses that a heat treatment at 250 °C for 10 min before each coating process could yield an amorphous multilayered film with no crack formed after calcinations at 600 °C. A crack-free Al₂O₃ film with a thickness up to 2 μm after 22 cycles of dip coating process could be produced and it showed an excellent antioxidation performance for steel substrate.     

Silica/Silicone Nanofilament Hybrid Coatings with Almost Perfect Superhydrophobicity

A facile method for the preparation of silica/silicone nanofilament hybrid coatings with almost perfect superhydrophobicity (contact angle=179.8° and sliding angle=1.3°) is presented. The coatings are obtained by dip‐coating of silica nanoparticles, followed by chemical vapor deposition of silicone nanofilaments. Predominant growth of silicone nanofilaments onto aggregated silica nanoparticles generates a two‐tier structure. The effect of silica nanoparticle size on the growth of silicone nanofilaments, along with their anti‐wetting properties and transparency are investigated in detail. Surface roughness and anti‐wetting properties can be simply regulated by controlling the size of silica nanoparticles.     

A high-throughput screening method for the exploration of optimal curing parameters and resistance to solvents of NANOMER®coating materials

A high-throughput screening method for the exploration of optimal curing parameters and resistance to solvents of NANOMER® coating materials based on the temperature-dependent swellability was developed. The screening method was first tested using a model sol made of pre-hydrolyzed (3-glycidoxypropyl)triethoxysilane (GPTES), tetraethoxysilane (TEOS), (heptadecafluoro-1,1,2,2-tetrahydrodecyl)triethoxysilane (FTS) and zirconium complex (prepared of zirconium-tert-butoxide complexed with acetylacetonate) charged with reactive diluent trimethylolpropan-triglycidether and defined amounts of fluorescein and cured at different temperatures. Afterwards, fluorescein was extracted with sodium hydroxide solution and the optical density of the supernatant of all samples was measured at 490 nm which is sensitive to the dye concentration. The optical density (OD) correlates with the degree of curing. According to this screening a temperature $CDATA \geq 140 ^\circA high-throughput screening method for the exploration of optimal curing parameters and resistance to solvents of NANOMER? coating materials based on the temperature-dependent swellability was developed. The screening method was first tested using a model sol made of pre-hydrolyzed (3-glycidoxypropyl)triethoxysilane (GPTES), tetraethoxysilane (TEOS), (heptadecafluoro-1,1,2,2-tetrahydrodecyl)triethoxysilane (FTS) and zirconium complex (prepared of zirconium-tert-butoxide complexed with acetylacetonate) charged with reactive diluent trimethylolpropan-triglycidether and defined amounts of fluorescein and cured at different temperatures. Afterwards, fluorescein was extracted with sodium hydroxide solution and the optical density of the supernatant of all samples was measured at 490 nm which is sensitive to the dye concentration. The optical density (OD) correlates with the degree of curing. According to this screening a temperature C is necessary for proper curing. The time dependence of extraction reveals information on resistance against sodium hydroxide solution, i. e. alkali resistance. The time dependent extraction of fluorescein at C of coatings cured at 100 and 140°C, respectively, shows a better resistance against 0.1 M sodium hydroxide solution for the one cured at 140°C, especially in the time range 10–60 min. The whole process — sol preparation, mixing of sols with dye, extraction, and optical spectroscopy—can be performed automatically. Further testes were made to proof the usability of this process. 96 hybrid materials were screened in regard to their alkali resistance and finally, a total number of 14 clear organic-inorganic hybrid coating systems with improved stability against sodium hydroxide solution were derived from this study.