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This article explores the preparation and characterization of ethyl cellulose-graphene oxide (EC-GO) composite membranes for dye adsorption. The addition of GO to the EC matrix improved the membranes' surface wettability and dye adsorption capacity. Various techniques, such as scanning electron microscopy and UV-visible spectroscopy, were used to characterize the membranes. The study found that the adsorption properties varied based on contact angle values and followed pseudo-second-order kinetics. The research highlights the potential of EC-GO composite membranes for water treatment applications, specifically in dye removal from wastewater. [Extracted from the article]

Pervaporation is still regarded as an emergent process, with a great potential to be an alternative to classical separation processes, with technical advantages. Chitosan is considered a promising material in next-generation pervaporation membranes, especially hybrid and mixed matrix membranes. This study aimed to evaluate the effect of fillers such as calcium carbonate, kaolinite, graphene, and graphene oxide, added separately at the concentration of 1 wt.%, on the mechanic and physical-chemical properties, microstructure, and hydrophilic pervaporation performance of chitosan membranes cross-linked with glutaraldehyde. The fillers influenced the mechanical and physicochemical properties of the membranes differently. Relative to the hydrophilic pervaporation tests, the presence of calcium carbonate and kaolinite increased membrane efficiency (αW/E of 1,777 and 1,225 against 611 in the control), whereas graphene reduced the permeate flux (0.341 kg·m−2·h−1 against 0.397 kg·m−2·h−1 in the control). The addition of graphene oxide increased the flux and permeability of ethanol (0.089 kg·m−2·h−1 and 8.66·10−14 kg·m−1·s−1·Pa−1 against 0.019 kg·m−2·h−1 and 1.74·10−14 kg·m−1·s−1·Pa−1 in the control), unlike the other fillers, which had no significant influence on this parameter. Thus, the membranes containing the fillers calcium carbonate and kaolinite were more suited for use in hydrophilic pervaporation (PSI of 842 and 561 against 228 in the control). Graphene did not affect membrane properties (αW/E of 398 and PSI of 127). Graphene oxide (αW/E of 174 and PSI of 72) may be considered as an alternative and starting point for the development and research of mixed matrix membranes based on chitosan to be used in target-organophilic pervaporation. [ABSTRACT FROM AUTHOR]

• Water vapor membrane permeation under supercritical carbon dioxide conditions. • Pressures up to 185 bar for mixed H 2 O/CO 2 and H 2 O/N 2 feeds in PDMS membranes. • Water vapor transport through the membrane determined by matrix fluid (CO 2 or N 2). • H 2 O and CO 2 transported at comparable rate towards the membrane surface. • For the H 2 O/CO 2 mixture, mass transfer resistance decreases to zero at high pressure. Water vapor permeation under supercritical carbon dioxide (scCO 2) conditions through dense polydimethylsiloxane (PDMS) was investigated up to pressure of 185 bars to evaluate the regenerability of scCO 2 as desiccant to dehydrate fresh products that are prone to product deterioration during conventional drying. This study experimentally examined the impact of concentration polarization on the H 2 O vapor permeation through dense PDMS membranes in the presence of sub- and supercritical CO 2. The results were compared to a system containing N 2 instead of CO 2. For the CO 2 system, the residual mass transfer resistance, which excludes the membrane layer resistance, decreased down to zero with increasing feed pressure, at 90 bar. This is the result of the convergence of the H 2 O contents of the feed bulk and permeate, which leads to a change of the main H 2 O transport mechanism within the feed boundary layer from diffusion to convection. Here the H 2 O and CO 2 molecules are transported with comparable speed towards the membrane surface. For the system with N 2 , the opposite trend was found, due to the maintained significant difference in transport speed between H 2 O and N 2 even at elevated pressures. Consequently, the water vapor transport rate through the PDMS membrane is governed by the type of matrix fluid (CO 2 or N 2). [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Adsorbable foreign gas affects mass transfer through dense membranes. • Deposition of aerosol nanoparticles on side surface of membrane decreases permeance. • Intensification of mass transfer through membranes by radiation is considered. Abstract It is known that fouling of membranes decreases their performance. New modern types of membranes which are used for separation of gas mixtures (e.g. supported ionic liquid and graphene-based membranes) require the methods for cleaning which differ from the methods used in classical membrane technology (e.g. backflushing). Mass transfer in these membranes can be blocked by the adsorbed foreign gas molecules or/and aerosol nanoparticles which are present in a gas phase near the feed side surface of the membranes. The new method of the intensification of mass transfer through the membranes by resonance radiation is considered. It is shown that resonance radiation, leading to selective excitation of the foreign gas molecules and a change in their sticking coefficient and the rate coefficient of desorption as well as to heating of the membrane, can reduce the affinity constant of the foreign gas that in turn decreases the surface coverage and the blocking effect of the adsorbed foreign gas molecules. A model is given for the transport of gas molecules through a dense flat membrane with the deposition of aerosol particles on the feed side surface of the membrane. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Pressure where CO 2 permeability reaches maximum is temperature dependent. • Feed density and not intrinsic membrane property dictate CO 2 permeability profile. • Trend of CO 2 fluid density and concentration in PDMS are alike, at high pressures. • Phase change from gaseous- to liquid-like CO 2 leads to altered permeation behavior. • Transition to liquid-like state leads to lowered CO 2 diffusion within the polymer. Abstract Supercritical carbon dioxide (scCO 2) is used in the food industry as a water-extracting drying agent. Once saturated with water, the scCO 2 needs to be regenerated. A promising way of drying scCO 2 is by using H 2 O permeable membranes. Ideally, these membranes demonstrate low CO 2 permeability. Here, we investigated the CO 2 permeability of three types of dense membranes, Nafion, Natural Rubber and PDMS, of which the latter in more detail because of its ease of handling. The experimental conditions, temperature and pressure, resulting in minimum CO 2 permeability (=losses) were explored. Even though the absolute CO 2 permeability depends on the intrinsic membrane material properties, its trend with increasing feed pressure is defined by the (supercritical) behavior of CO 2 , notably its density as a function of temperature and pressure. The data points to transitions within the supercritical regime, from the gaseous-like supercritical state to the liquid-like supercritical state, graphically visualized by the Widom line for CO 2 density. Sorption measurements with PDMS membranes confirm this behavior that follows the diffusion-solution theory. In the gaseous state, the (normalized) permeability follows the (normalized) solubility, indicating a constant CO 2 diffusivity. With increasing pressure and when entering the liquid-like (supercritical) regime, the diffusivity drops, resulting in a (normalized) permeability that starts to lag behind the (normalized) solubility. [ABSTRACT FROM AUTHOR]

Membrane technologies are nowadays widely used; especially various types of filtration or reverse osmosis in households, desalination plants, pharmaceutical applications etc. Facing water pollution, they are also applied to eliminate emerging contaminants from water. Incomplete knowledge directs the composition of membranes towards more and more dense materials known for their higher selectivity compared to porous constituents. This paper evaluates advantages and disadvantages of well-known membrane materials that separate on the basis of particle size, usually exposed to a large amount of water, versus dense hydrophobic membranes with target transport of emerging contaminants through a selective barrier. In addition, the authors present several membrane processes employing the second type of membrane.

Background: The use of novel materials as an artificial extracellular matrix for stem cell growth is a current strategy of increasing interest for regenerative medicine. Here, we prepare thermal-remolded membrane scaffolds from poly(3-hydroxybutyrate) grafted with 2-amino-ethyl methacrylate hydrochloride. However, it is unclear whether these membranes are useful for tissue engineering. Results: The mechanical properties, tribology, and morphology of the dense membranes were assessed. The results show that tensile strain at break and roughness of the compressed membrane decrease with increasing graft degree. Moreover, graft copolymer membranes showed lower resistance to scratching, greater degree of swelling and higher brittleness than un-grafted P(3HB) films. Thus, it effectively supports the growth of dermal fibroblast, as demonstrated by epifluorescence microscopy. Conclusions: It is concluded that the developedmembrane can be properly used in is the restoration of skin tissue. [ABSTRACT FROM AUTHOR]

Polydimethylsiloxane PDMS, polyethylene PE (the most used polymer in food packaging) and pectin (biopolymer potentially used as wound dressing material and in food packaging) were characterised in terms of their gas transport properties. This characterisation was performed by on-line mass-spectrometry, MS, with the upstream and downstream compartments of the membrane unit at atmospheric pressure, in order to mimic the operating conditions of the applications addressed. A simple, direct restriction was used for allowing the downstream gas mixture to reach the mass spectrometer detector. Monitoring of gas permeation by on-line mass spectrometry proved to be a highly precise and reproducible technique, which makes possible the study of multicomponent gas mixtures in dry and humidified gas conditions, without requiring sampling and additional off-line procedures and analysis. Data acquisition, with time intervals as short as one second, makes possible the comparative study of permeation processes of each gas present in different feed streams (pure gases, gas mixtures under dry and humidified conditions) during the initial transient period, allowing for inferring about solute-membrane interactions. Information about steady-state transport may also be acquired, and are in agreement with values reported in literature. [ABSTRACT FROM AUTHOR]

Dense palladium membranes have increasing interest for ultra-pure hydrogen production compared to established technologies such as pressure swing adsorption and cryogenic distillation, allowing the separation in one step with no associated energy consumption. Alloying elements are used in combination with palladium in these membranes to change the membrane properties. This article presents a review of palladium alloy membranes for hydrogen purification, including permeability data and other relevant characteristics of the alloys. Further developments in this research field are expected to focus on the use of ternary alloys with enhanced physical and chemical properties, and the use of computational methods to enable a faster screening of promising alloys. [ABSTRACT FROM PUBLISHER]

O desenvolvimento de sistemas não-poluentes tem sido cada vez mais necessário para atender às exigências ambientais. Neste trabalho foram sintetizadas formulações de poliuretanos à base de água para a obtenção de membranas densas cujas propriedades mecânicas e de permeação a CO2 e N2 foram avaliadas. Foram empregados como monômeros polibutadieno líquido hidroxilado (HTPB), poli(glicol propilênico) (PPG), diisocianato de isoforona (IPDI) e ácido dimetilolpropiônico (DMPA). Os grupos carboxílicos foram neutralizados com trietilamina (TEA) e o extensor de cadeia utilizado foi a etilenodiamina (EDA). As membranas foram obtidas como filmes vazados a partir das dispersões aquosas. Os resultados mostraram que o aumento no teor de HTPB na formulação levou a uma maior resistência mecânica bem como a um aumento na permeabilidade e na seletividade das membranas a CO2.The performance of dense membranes based on nonpolluting systems of polyurethane aqueous dispersions was evaluated. The mechanical properties and the selectivity and permeability to CO2 and N2 were determined. The aqueous systems were based on hydroxyl-terminated polybutadiene (HTPB), poly(propylene glycol) (PPG), isophorone diisocyanate (IPDI), and dimethylolpropionic acid (DMPA). The membranes obtained from cast films provided higher permeability and selectivity to CO2 as the HTPB content increased. The tensile strength and the modulus values of the materials increased and the elongation decreased with higher amounts of HTPB. As a result, the presence of HTPB improved the mechanical resistance, the permeability and the selectivity to CO2 of the polyurethane membranes.

In this study, a green approach to prepare both porous and dense antifouling membranes was developed through solvent-free bulk polymerization of the casting solution containing 2-hydroxyethyl methacrylate (HEMA) and pre-dispersed silica nanoparticles in two glass sheets under pressure. Porous polyHEMA membranes were prepared via removing the silica nanoparticles embedded in the polymer matrix. Dense poly(HEMA/MAA)/SiO 2 membranes were fabricated by adding methacrylic acid (MAA) as co-monomer without removing the silica nanoparticles. Membrane thickness could be conveniently controlled by varying the distance between the two slide glasses. Field emission scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS) and water contact angle measurement were employed to characterize the morphology and surface chemical composition of the resultant membranes. The porous polyHEMA membranes exhibited high efficiency in purification of bovine serum albumin (BSA) from BSA/yeast solution while the dense poly(HEMA/MAA)/SiO 2 membranes exhibited high rejection of orange GII. Both porous membranes and dense membranes exhibited strong hydrophilicity as a result of hydrophilic monomer HEMA, leading to good antifouling properties. [ABSTRACT FROM AUTHOR]

In order to concentrate ethanol from a dilute aqueous solution produced by bio-fermentation, two kinds of hydrophilic and hydrophobic polymer membranes were prepared. Hydrophilic membranes, such as quartemized chitosan (q-Chito) membranes cross-linked with glutaraldehyde and hybridized q-Chito membranes with tetraethoxysilane, showed very high water/ethanol selectivity and high permeation rate for the dehydration of ethanol/water azeotropes using pervaporation (PV) and evapomeation (EV). On the other hand, hydrophobic poly[1-(trimethylsilyl)-1-propyne] (PTMSP) and poly(dimethylsiloxane) (PDMS) membranes were used to directly concentrate ethanol from dilute bio-ethanol. When the surface of the PTMSP membrane was treated with a polymeric surface modifier, the ethanol permeselectivity improved remarkably. The DMS phase forms the continuous phase in microphase separated DMS-g-MMA membranes. We could show that this significantly increases ethanol permselectivity. Dense PTMSP and PDMS membranes for temperature-difference controlled evapomeation (TDEV) showed higher ethanol permselectivity than those used in PV. Furthermore, porous PDMS membranes showed both higher permeation rate and ethanol permselectivity in TDEV compared to dense PDMS membranes. [ABSTRACT FROM AUTHOR]

Silk fibroin has been widely explored for many biomedical applications, due to its biocompatibility and biodegradability. Sterilization is a fundamental step in biomaterials processing and it must not jeopardize the functionality of medical devices. The aim of this study was to analyze the influence of different sterilization methods in the physical, chemical, and biological characteristics of dense and porous silk fibroin membranes. Silk fibroin membranes were treated by several procedures: immersion in 70% ethanol solution, ultraviolet radiation, autoclave, ethylene oxide, and gamma radiation, and were analyzed by scanning electron microscopy, Fourier-transformed infrared spectroscopy (FTIR), X-ray diffraction, tensile strength and in vitro cytotoxicity to Chinese hamster ovary cells. The results indicated that the sterilization methods did not cause perceivable morphological changes in the membranes and the membranes were not toxic to cells. The sterilization methods that used organic solvent or an increased humidity and/or temperature (70% ethanol, autoclave, and ethylene oxide) increased the silk II content in the membranes: the dense membranes became more brittle, while the porous membranes showed increased strength at break. Membranes that underwent sterilization by UV and gamma radiation presented properties similar to the nonsterilized membranes, mainly for tensile strength and FTIR results. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 102B: 869-876, 2014. [ABSTRACT FROM AUTHOR]

Highlights: [•] We have prepared a fluorogenic sensory polymer for the detection and quantification of water. [•] Fluorogenic sensory polymer strips have been prepared from polymer films. [•] The strips permit the easy and rapid quantification of the water content of organic solvents. [•] The sensory strips permit the easy and rapid determination of the humidity in air. [ABSTRACT FROM AUTHOR]

Abstract: This paper describes the preparation of a hydrophilic copolymer membrane with two comonomers: 1-vinyl-2-pyrrolidone (commercial) and a new water insoluble piperazinedione derivative, which is a fluorogenic mercury sensing motif. The dense membrane permitted the fluorogenic detection of Hg2+ in aqueous media. The sensitivity of the membrane this cation was significantly high, with a detection limit of 10ppt. This limit of detection is much lower than that of DMSO/water solutions of the sensing monomer, which is 10ppb, and significantly lower than the maximum contaminant level (EPA) in drinking water, 2ppb. [Copyright &y& Elsevier]

Abstract: This paper investigates the possibility of increasing the energetic efficiency of a hydrogen production industrial plant through the introduction of dense membranes in the steam reforming process. A simulation tool, developed in the Aspen Plus® framework has been used to model a 1500Nm3/h hydrogen production plant. Besides the original plant layout with a PSA purification unit, three different membrane installation configurations have been considered: before the shift reactor, at the exit of the shift reactor and before the PSA unit. For all the three configurations the plant capacity was set at 75%, changing the permeated hydrogen flow. The membrane surface and cost were also estimated for each solution. Membranes installation just after the shift reactor gives the best solution in terms of both plant energetic efficiency and cost reduction. [Copyright &y& Elsevier]

Abstract: The possibility of producing valued devices from low cost natural resources is a subject of broad interest. The present study explores the preparation and characterization of silk fibroin dense membranes using waste silk fibers from textile processing. Morphology, crystallinity, thermal resistance and cytotoxicity of membranes as well as the changes on the secondary structure of silk fibroin were analyzed after undergoing treatment with ethanol. Membranes presented amorphous patterns as determined via X-ray diffraction. The secondary structure of silk fibroin on dense membranes was either random coil (silk I) or β-sheet (silk II), before and after ethanol treatment, respectively. The sterilized membranes presented no cytotoxicity to endothelial cells during in vitro assays. This fact stresses the material potential to be used in the fabrication of biomaterials, as coatings of cardiovascular devices and as membranes for wound dressing or drug delivery systems. [Copyright &y& Elsevier]

New polymer nanocomposites consist of poly(phenylene isophtalamide) (PA) modified by carbon nanotubes (CNT) were obtained by the solid state interaction method to prepare dense membranes. The investigation of the PA/CNT nanocomposites was made by Raman spectroscopy. The morphology of the dense membrane was analyzed by SEM. The transport properties of the dense polyamide membranes modified by 2 and 5 wt% CNT were studied in pervaporation of methanol/ methyl tert-butyl ether mixture. It was shown that the selectivity with respect to methanol and permeability were the highest for membranes containing 2 wt% CNT as compared to membranes of pure PA and containing 5 wt% CNT. To analyze transport properties the sorption tests and contact angle measurements were employed. [ABSTRACT FROM AUTHOR]

Abstract: Aromatic polyamides, designed for evaluation as gas separation membranes, were processed into dense films, whose properties were measured with special emphasis on their mechanical and thermal properties. The polymers had been synthesized from monomers bearing side substituents, such as methyl, iso-propyl or tert-butyl, and various hinge-like connecting linkages of p-phenylene moieties, which yielded amorphous aromatic polyamides, with improved solubility, high glass transition temperatures (over 250°C) and excellent mechanical properties (tensile strength about 100MPa, and moduli about 2.0GPa). The permeability of the polymer films were investigated using helium, oxygen, nitrogen, carbon dioxide and methane. Gas permeability typically increased with increasing free volume, and, in general, free volume could be related to the chemical structure. The analysis of the transport parameters (permeability, diffusivity and solubility coefficients) as a function of the chemical structure, confirmed the predominant role of the side substituents and of the linking groups connecting phenylene units on the permeation properties. Besides, a molecular modelling study carried out via computational chemistry, made it clear that an acceptable theoretical explanation can be given of how the nature of hinge groups between aromatic rings can affect torsional mobility and gas diffusion of aromatic polyamides. The experimental aromatic polyamides of this report, as a whole, showed a favourable combination of permeability–selectivity, better than that of conventional polyamides and that of most engineering thermoplastics, confirming the hypothesis that the incorporation of side bulky substituents is a convenient approach to hinder the inherently efficient chain packing of polyamides. [Copyright &y& Elsevier]

Abstract: Novel cermet (i.e. ceramic–metal composite) membranes have been developed to separate hydrogen from mixed gases, particularly product streams generated during coal gasification and/or methane reforming. Hydrogen separation with these membranes is non-galvanic, i.e. it does not use electrodes or an external power supply to drive the separation, and hydrogen selectivity is nearly 100% because the membranes contain no interconnected porosity. The hydrogen permeation rate has been measured as a function of temperature (500–900°C), membrane thickness (≈22–210μm), and partial pressure of hydrogen (0.04–1.0atm) in the feed gas. The hydrogen flux varied linearly with the inverse of membrane thickness, and reached ≈20cm3(STP)/mincm2 for a membrane with a thickness of ≈22μm at 900°C with 100% H2 (at ambient pressure) as the feed gas. The results indicate that the hydrogen flux is limited by bulk diffusion and might be higher for a thinner (<22μm) membrane. Some of the membranes were tested in a simulated syngas mixture containing H2, CO, CO2, and CH4, and showed no degradation in performance. Hydrogen flux measurements made in H2S-containing atmospheres for times approaching ≈270h showed that a 200-μm-thick cermet membrane was stable in gases containing up to ≈400ppm H2S. While longer-term studies are needed, these results suggest that the cermet membranes may be suitable for practical hydrogen separation applications. [Copyright &y& Elsevier]

Powder of gadolinia-doped ceria (GDC, Gd0.1Ce0.9O1.95), prepared using a glycine–nitrate process, is used to fabricate anode-supported solid oxide fuel cells (SOFCs) by dry pressing. The microstructure, conductivity, and electrochemical properties of the GDC powder are studied as a function of sintering conditions. Results show that the relative density of the GDC electrolyte is about 92%, 95%, and 97%, respectively, when sintered at 1250, 1350, and 1450 °C for 5 h, indicating that the electrolyte can be adequately densified at a relatively low firing temperature (1250 °C). The conductivities of the electrolytes, however, are relatively insensitive to the sintering temperature. Using humidified (3% H2O) hydrogen as fuel and stationary air as oxidant, the electrochemical properties of the anodes are studied at temperatures from 400 to 600 °C. Impedance analysis indicates that the cathodic interfacial polarization is much larger than the anodic polarization under testing conditions. However, anodes sintered at a lower temperature exhibit better electrochemical performance than those sintered at a higher temperature. [Copyright &y& Elsevier]

Redox flow battery (RFB) is promising in grid-scale energy storage, and potentially applicable for facilitating the harvest of the intermittent renewable power sources, like wind and solar, and stabilizing the power grid. Early RFBs are based on aqueous electrolytes and the all-vanadium as well as Zn/Br systems have been demonstrated in close commercial scale. Non-aqueous RFBs (NARFBs) are the second-generation flow batteries based on organic solvent which have potentially much wider electrochemical window, and thus possible much higher energy density, and temperature window than those of the aqueous systems. As a crucial component of NARFBs, the membrane serves to prevent the crossover of the positive and negative active species whilst facilitating the transfer of the supporting electrolyte ions. However, the membranes utilized in the state-of-the-art publications still need great improvements in performance. In this article, the fundamentals, classifications, and performances of the membranes in NARFB are introduced. The recent progresses and challenges on the innovation of NARFB membranes are summarized. A perspective on the near future developments of NARFB membranes are presented. The composite membranes are likely the promising direction to forward the development of the NARFB technologies. [Display omitted] • The first review article on the state-of-the-art membranes in NARFBs. • Ion transfer mechanism and mathematical models are summarized. • Strategies to improve the performance of membrane in NARFBs are proposed. [ABSTRACT FROM AUTHOR]

Oxygen concentration cells, with dense dual phase composite membranes made from erbia-stabilized bismuth oxide and a noble metal (Au, Ag), were investigated in the temperature range 650–850°C under controlled oxygen partial pressure gradients. An electrochemical treatment was applied to interpretation of the oxygen permeation data. It is found that the composite membranes exhibit high oxygen permeability relative to the single phase bismuth oxide, since oxygen ions and electrons are allowed to transport through the oxide and metal phase, respectively. The oxygen permeability of the silver-containing composite is at least one order higher than that of the gold-containing one, which can be explained by the fact that silver has a higher catalytic activity than gold for the surface oxygen exchange reaction and thus less limitations are exerted on the overall oxygen transport. [ABSTRACT FROM AUTHOR]

Membrane technologies are nowadays widely used; especially various types of filtration or reverse osmosis in households, desalination plants, pharmaceutical applications etc. Facing water pollution, they are also applied to eliminate emerging contaminants from water. Incomplete knowledge directs the composition of membranes towards more and more dense materials known for their higher selectivity compared to porous constituents. This paper evaluates advantages and disadvantages of well-known membrane materials that separate on the basis of particle size, usually exposed to a large amount of water, versus dense hydrophobic membranes with target transport of emerging contaminants through a selective barrier. In addition, the authors present several membrane processes employing the second type of membrane. [ABSTRACT FROM AUTHOR]

Silk fibroin has been widely explored for many biomedical applications, due to its biocompatibility and biodegradability. Sterilization is a fundamental step in biomaterials processing and it must not jeopardize the functionality of medical devices. The aim of this study was to analyze the influence of different sterilization methods in the physical, chemical, and biological characteristics of dense and porous silk fibroin membranes. Silk fibroin membranes were treated by several procedures: immersion in 70% ethanol solution, ultraviolet radiation, autoclave, ethylene oxide, and gamma radiation, and were analyzed by scanning electron microscopy, Fourier-transformed infrared spectroscopy (FTIR), X-ray diffraction, tensile strength and in vitro cytotoxicity to Chinese hamster ovary cells. The results indicated that the sterilization methods did not cause perceivable morphological changes in the membranes and the membranes were not toxic to cells. The sterilization methods that used organic solvent or an increased humidity and/or temperature (70% ethanol, autoclave, and ethylene oxide) increased the silk II content in the membranes: the dense membranes became more brittle, while the porous membranes showed increased strength at break. Membranes that underwent sterilization by UV and gamma radiation presented properties similar to the nonsterilized membranes, mainly for tensile strength and FTIR results., (Copyright © 2013 Wiley Periodicals, Inc.)