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Supported cellulose ultrafiltration membranes are cast from a cellulose-ionic liquid solution by the immersion precipitation technique. The effects of coagulation bath temperature and polymer concentration in the casting solution on the membrane morphology, wettability, pure water flux, molecular weight cut-off, and fouling resistance are studied. Scanning electron microscopy, contact angle measurements, atomic force microscopy, and filtration experiments are carried out in order to characterise the obtained ultrafiltration cellulose membranes. The results show the effect of coagulation bath temperature and polymer concentration on the surface morphology and properties of cellulose ultrafiltration membranes. Optimisation of the two parameters leads to the creation of dense membranes with good pure water fluxes and proven fouling resistance towards humic acid water solutions. Publishers version

We present surface modification of thin-film-composite (TFC) polyamide (PA) reverse osmosis (RO) membrane by atomic layer deposition (ALD) process using trimethylaluminium (AlMe 3 ). The aim of the inorganic ALD coating is to improve the anti-fouling performance of TFC PA membranes. The ALD processing parameters were systematically studied because of the lack of previous investigations of the ALD coated RO membranes. Two different processing temperatures (70 °C and 100 °C) and three different ALD cycles (10, 50 and 100) were used to deposit the Al 2 O 3 ALD coatings on TFC PA membranes. The ALD process parameters affected on the hydrophilicity and the surface polarity as well as on the surface roughness of the coated membranes. The bacteria attachment test results indicated that the lowest number of Pseudomonas aeruginosa cells was adhered on the most hydrophilic and polar surface, among the ALD coated membranes. RO tests showed the effect of ALD coating on the water and salt permeability as well as on the salt rejection of the membranes.

Anti-adhesion and antimicrobial coatings were prepared and applied on commercial thin-film-composite (TFC) polyamide (PA) membrane to enhance anti-biofouling performance. Polyvinyl alcohol (PVA) coating was modified with cationic polyhexamethylene guanidine hydrochloride (PHMG) polymer to obtain antimicrobial performance. ATR-FTIR, SEM and AFM investigated the surface chemistry and morphology of the coated membranes. The contact angle measurement was used to determine hydrophilicity and surface energy. All coated membranes revealed more hydrophilic and lower surface roughness compared to uncoated membrane. Lower number of adhered Pseudomonas aeruginosa (P. aeruginosa) bacteria was detected on coated membranes, indicating anti-adhesion performance. The colony forming unit (CFU) and diffusion inhibition zone (DIZ) tests determined antimicrobial activity of the coated membranes against Escherichia coli (E. coli) and Bacillus subtilis (B. subtilis), showing the antimicrobial performance of PHMG. The results suggested that an optimal anti-fouling surface could be obtained applying a coating, which combines anti-adhesion and antimicrobial performance.

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.

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.

Two silane-based hybrid coatings were developed to modify the surface energy of phenolic resin impregnated paper. The coated paper samples were further pressed onto surfaces of plywood. The surface properties and water repellence of coated paper were investigated by AFM, XPS and water contact angle measurements. The water absorption of plywood with pressed paper was studied by water uptake tests. It was found that the sol-gel coatings had slightly improved the water repellence of the impregnated paper. The water absorption of plywood was also slightly decreased.

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.

Polystyrene (PS, 1), polycaprolactone homopolymers (PCL, 2) and 3-Iodo-2-propynyl n-butylcarbamate (IPBC, 3) were physically mixed in dichloromethane (DCM) and processed into solid microspheres by using emulsion solvent evaporation method. Five different compositions with varying PS/PCL ratio were tested. The phase morphology of the microspheres was studied using Phase imaging atomic force microscopy (AFM) of polished cross-sections. Scanning electron microscopy was utilized to assess the distribution of IPBC in the polymer microspheres. The phase separation of the PS and PCL polymers in solvent cast films was assessed using polarized light optical microscopy of 11 polymer blends (0-100 wt-% PCL in PS). The PS/PCL-IPBC microspheres were incubated in water at RT and the release of IPBC was studied using high performance liquid chromatography (HPLC) at time points 1, 7 and 30 days. The microspheres dispersed in water borne outdoor paint matrix were tested for their antifouling activity against moulds in vitro.

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.

This study investigates the bacterial anti-adhesion performance of uncoated and coated reverse osmosis (RO) membranes. All the membranes were commercially available fully-aromatic thin-film-composite (TFC) polyamide (PA) membranes. Two of the TFC PA membranes (SW30 and BW30) were coated using polyvinyl alcohol (PVA) coating, while the other three membranes (LE, XLE and NF90) were uncoated. Among the characterised TFC PA membranes, the PVA coated were more hydrophilic and their surface energy was higher in comparison to uncoated. In addition, the PVA coated membranes had lower surface roughness. AFM interaction force measurement demonstrated higher repellence performance for the more polar surface. Bacteria attachment test showed differences between the coated and the uncoated membranes. Indeed, the increase in hydrophilicity and surface polarity showed decrease in the attachment of Pseudomonas aeruginosa cells. Moreover, the results demonstrated that the surface polarity showed better correlation with the attachment of the bacteria. In addition, the type of the surface roughness may somehow contribute to the bacteria repellence.

Plasma deposition equipment was developed and installed at a pilot extrusion coating line for reel-to-reel substrates. Hexamethyldisiloxane was used as a siloxane precursor for the atmospheric plasma deposition of siloxane coatings on substrates of three different categories: paper, polyethylene-coated paper, and textile materials (woven cotton fabric and polypropylene nonwoven). SEM, H2O contact angle measurements, heat sealability, and water vapor barrier measurements were carried out to characterize the composition and surface structure of the samples. The potential of the method and the equipment was shown by the coatings, ranging to micrometer scale. With selected samples, hydrophobic coating was shown to form at speeds up to 100 m/min.

Thin (25 nm) and highly uniform Al2O3 coatings have been deposited at relatively low temperature of 80 and 100°C onto various bio-based polymeric materials employing the atomic layer deposition (ALD) technique. The work demonstrates that the ALD-grown Al2O3 coating significantly enhances the oxygen and water vapor barrier performance of these materials. Promising barrier properties were revealed for polylactide-coated board, hemicellulose-coated board as well as various biopolymer (polylactide, pectin and nano-fibrillated cellulose) films.