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Single-layer films from cellulose nanofibrils on a plastic support were coated with sol–gel coated with inorganic–organic copolymers (ORMOCER®s), consisting of inorganic Si–O–Si-based networks combined with ceramic (Al–O– and Zr–O–) groups and special organic fluoroalkyl chain containing functional groups. Sol–gel coatings decreased the surface hydrophilicity and water vapor transmission rate. The water contact angle of uncoated films was 24°, indicating high affinity between water and the cellulose nanofibrils. All sol–gel coatings tested increased the surface hydrophobicity with the contact angles ranging between 54° and 102°. The water vapor transmission rates varied between 230 and 410 g/m2/day. With UV curable highly organically crosslinked coating, the water vapor transmission rate was decreased by 77% as compared to uncoated film. The uncoated film had oxygen transmission rates of 0.7 and 107 cc/m2/day at 50% and 80% RH, respectively. At high humidity conditions, the films tended to swell, thus allowing permeation to increase. Sol–gel coatings significantly improved the oxygen barrier properties especially at 80% RH. The transmission rates varied between 0.4 and 0.5 cc/m2/day (50% RH) and between 51 and 86 cc/m2/day (80% RH).

Two organic–inorganic hybrid sol–gel coatings were developed in order to modify the surface energy and moisture behaviour of the commercial impregnated paper. The surface characteristics of the paper samples were studied by scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), atomic force microscopy (AFM), attenuated total reflectance Fourier transform infrared spectrometry (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and time of flight secondary ion mass spectroscopy (ToF-SIMS). It was found that the applied sol–gel coatings as well as the curing process changed the surface structural and chemical properties of the impregnated paper. The chemical bonding between the hydroxyl groups present on paper surface and silanol groups from sol–gel coatings was confirmed by the FTIR spectra. The measured surface energies divided into polar and dispersive components indicated that the coating B resulted in less polar surface than did the coating A which was more polar than the reference (the impregnated paper with water and heat treatment). Coating B brought about the lowest total surface energy. It was obtained that the water repellence of the impregnated paper was improved by both coatings and the curing process.

Two hybrid coatings synthesized by using alkoxysilanes as precursors in a sol–gel process, differing from each other in terms of the organic components in alkoxysilanes, have been developed to improve the water repellent properties of base paper. The sol–gel-coated base paper samples were characterized by scanning electron microscopy, atomic force microscopy, confocal laser scanning microscopy, X-ray photoelectron spectroscopy, time-of-flight secondary ion mass spectrometry, and contact angle measurements. The sol–gel coatings were found to clearly change the surface properties of base paper. Thin coating layers were formed on base paper surfaces. The topographical data indicated the formation of discontinuous thin films; the time-of-flight secondary ion mass spectrometry analyses confirmed that the coatings were covering the fibres but only partially covered the fibre–fibre intersections. Water and the subsequent heat treatment used as a reference treatment reduced the surface roughness and porosity and slightly changed the surface chemistry of the base paper. The wettability and absorptivity of base paper was clearly reduced by the applied coatings. Copyright © 2011 John Wiley & Sons, Ltd.

The surface morphology and moisture behaviour of pine (Pinus sylvestris) sapwood and heat-treated spruce (Picea abies) deposited with two types of silane-based sol–gel coatings were studied by atomic force microscopy (AFM) and water contact angle measurement. The chemical composition and distribution of sol–gel coatings on wood surfaces were investigated by X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The AFM images revealed that the sol–gel coatings applied by spreading covered the fine structure of the wood substrates. The surface roughness analysis of the AFM topographical images indicated that the sol–gel coatings, especially the one with short aliphatic chain, had a tendency to smooth the wood surface. The XPS results confirmed that the sol–gel coatings had successfully deposited onto pine sapwood and heat-treated spruce changing their surface chemistries. ToF-SIMS images showing Si ion distribution on treated surfaces revealed that the coatings fully covered pine sapwood surfaces. The thin coating layers formed on heat-treated spruce surfaces followed the original wood surface structure. The contact angle measurements indicated that the water repellent properties of both pine and heat-treated spruce were improved to certain extent by the sol–gel coatings.

The surface pretreatments of the austenitic stainless steel and copper surfaces for the sol–gel coating were carried out by chemical, plasma electrolytic or CO2 cryoblasting techniques. With the austenitic stainless steel the smoothest surfaces were obtained with plasma electrolytic cleaning, after which the measured contact angles of water were clearly decreased revealing improved hydrophilicity. As well with the copper samples the smooth surface and improved hydrophilicity was obtained with the plasma electrolytic cleaning, but oxide layer formed to the copper surface immediately after the treatment. CO2 cryoblasting provided rough surface with wetting properties close to the original surface both for austenitic stainless steel and copper surfaces. CO2 cryoblasting provided best appearance for the copper surface because no oxidation happened with that treatment. XPS and SIMS studies showed that with the plasma electrolytic treatment the surface layer of the austenitic stainless steel enriched of chromium and the oxide layer formed on the surface was less than 10 nm thick. With the chemical cleaning and CO2 cryoblasting, the chromium enrichment to the stainless steel surface was less. However XPS and SIMS studies showed that chemical treatment provided thinner oxide layer to copper surface than plasma electrolytic treatment.

Corrosion, fouling, and wearing of metal surfaces are the most common problems faced in industry as well as in environmental use. In the recent study, sol–gel based protective coatings were developed and deposited on different copper substrates. Different chemical pretreatments were used to enhance the adhesion and spreadability of coatings on copper surfaces. Substantial improvement of the corrosion resistance of sol–gel coated copper surfaces was obtained by a salt spray test. In addition, the sol–gel coatings increased hydrophobic and easy-to-clean properties of the copper surface. Variation of the curing temperature of the coatings caused changes in the morphology, adhesion, and topography of the sol–gel coatings. On the basis of the important information obtained in this study, the protective properties of sol–gel coatings can be tailored for copper and copper alloy substrates.

Two silane-based hybrid coatings were developed for surface modification of paper samples with an attempt to improve the hydrophobic properties of the paper surfaces. A phenolic resin was used along with the sol–gel coatings to impregnate the paper samples before they were pressed on to plywood surfaces. The surface characteristics of the sol–gel-coated paper were investigated by atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), confocal laser scanning microscopy (CLSM) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The surface chemical properties and water absorption of the laminated plywood was also evaluated. It was observed that the hybrid coatings had clearly different effect on the surface properties of the base paper compared to the industrially impregnated paper. The water absorption of the laminated plywood was decreased the most effectively by mixing the phenolic resin with the coating having an octyl group attached to the silane backbone.

Recently, inorganic–organic hybrid coatings produced by the sol–gel route have proven to be a potential protective treatment for wooden surfaces. In this study, the effect of curing process on simulated antisoiling properties of sol–gel coating was investigated. The sol–gel coating was spray-coated on pine sapwood and cured with different temperature and time combinations. The antisoiling properties were studied by measuring the water contact angle of the coating after different curing processes. In addition, abrasion resistance and contact angle of oleic acid were measured. An optical profilometer was used to investigate surface roughness of the coating. Sufficient hydro- and oleophobicity were obtained with all of the curing parameters. The comparison between curing parameters showed that lower temperature and 1–3 h curing time leads to significant improvement in the durability of the water and oil repellent properties of the coating.