Search

Introduction. The accumulation of oily wastewater in the environment is becoming an increasing threat to the ecosystem and human health. The modification of ultrafiltration PVDF membrane was investigated in order to create a hydrophilic layer on its surface, to improve performance and increase antifouling properties in the purification of oil-water emulsions.Materials and methods. PVDF hollow-fibre capillary membranes with 0.1 μm diameter pores were used. The membranes were subjected to two-step modification, which included treatment with tannic acid and subsequent oxidation with potassium permanganate in various buffer solutions. Motor oil, kerosene, distilled water and sodium dodecyl sulfate were used to create model water-in-oil emulsions. All oil-water emulsion separation experiments were performed while maintaining a constant filtration pressure of 1 bar on a prepared filter cell, in dead-end mode. The prepared model solutions were made with sodium dodecyl sulfate and contained the pollutant motor oil or kerosene. The filtrate after the membrane was sampled to determine the permeability and separation efficiency of the solutions. Surface modification had a positive effect on the retention efficiency of petroleum products. In the case of motor oil emulsion separation, the efficiency reached 99 %, and the content of oil products in all filtrate samples was below 0.4 mg/l. In the case of separation of kerosene emulsion there was observed a slight decrease in the efficiency of purification up to 95 %, the content of oil products was below 1.15 mg/l.Results. The results obtained showed a significant increase in throughput and separation efficiency. The specific membrane performance increased up to 143 % for motor oil separation and up to 67 % for kerosene separation.Conclusions. The modified membranes showed high petroleum product removal efficiency, up to 99 % for motor oil and up to 98 % for kerosene, also had high flux recovery rate (FRR) up to 91 %. The results obtained may be promising for scaling up.

The aim of this work was to the obtaining novel mixed-mode stationary phases with increased hydrophilicity and applying them in ion and hydrophilic interaction liquid chromatography. The resins were obtained by the sequential covalent attachment of branched polyethylenimine and polyelectrolytes synthesized from diepoxide and a secondary amine on the surface of epoxidized polystyrene–divinylbenzene. To increase the shielding degree of the polymer substrate, an additional polymerization of glycidol was carried out in the functional layer of the sorbent at an increased pH of the reaction medium. The synthesized phases possessed increased hydrophilicity compared to most resins based on a styrene–divinylbenzene copolymer with covalently attached layers. This was evidenced in the ion chromatography mode by a decrease in the relative retention of polarizable anions, weakly hydrated oxyhalides (up to a change in the elution order of the bromate), and haloacetic acids. In the hydrophilic interaction liquid chromatography mode, an increased hydrophilicity of the phases was confirmed by an increase in the retention factors of polar analytes, as well as by the reversal of the elution order of ascorbic and nicotinic acids as compared to the phases based on polystyrene–divinylbenzene presented in the literature. The low efficiency of the obtained stationary phases in the ion chromatography mode was noted, which is associated with slow mass transfer in the bulk polymer functional layer. The negative impact of the polymer layer on efficiency in hydrophilic interaction liquid chromatography is less pronounced due to the presumably smaller thickness of the part of the functional layer involved in this mode. The proposed method for the synthesis of resins ensures an increase in the efficiency, selectivity, and separation ability of sorbents in the hydrophilic interaction liquid chromatography mode as compared to phases based on a styrene–divinylbenzene copolymer described previously in the literature. The resulting highly hydrophilic resins makes it possible to separate a mixture of 9 nitrogenous bases and nucleosides in 18 min, 6 vitamins in 24 min, and 8 sugars in 11 min. Thus, the method of substrate hydrophilization proposed in this work is promising for improving the chromatographic characteristics of phases in the hydrophilic interaction liquid chromatography mode and can be used to create sorbents with increased selectivity and efficiency. [ABSTRACT FROM AUTHOR]

Two methods for increasing the degree of hydrophilization and shielding of a resin substrate based on a styrene–divinylbenzene copolymer with attached polyethylenimine quaterinized with glycidol are proposed. The first method is the polymerization of glycidol in a functional layer by varying the pH of the reaction medium, and the second one is the modification of the substrate by oxidizing double bonds on its surface to form anchor epoxy groups. It is demonstrated that, in the first case, the optimal approach is to add glycidol twice before and after adding an alkali, because, in this case, the first addition of glycidol is consumed for the quaternization of the polyamine, and the second addition—for the polymerization in ion-exchange centers. The novel method of substrate modification in combination with the developed method for creating hydrophilic layers made it possible to significantly reduce the retention of oxohalides, haloacetic acids, and polarizable anions in the suppressed ion chromatography mode and amino acids in hydrophilic interaction liquid chromatography mode up to a change in the elution order. The obtained stationary phases are suitable for the simultaneous determination of standard inorganic anions, oxohalides, and haloacetic or alkylphosphonic acids in an ion chromatography mode, and also for the separation of amino acids, sugars, and vitamins in a hydrophilic interaction liquid chromatography mode. [ABSTRACT FROM AUTHOR]

To expand the field of application of anion exchangers based on a copolymer of styrene and divinylbenzene with attached polyethyleneimine, quaternized with glycidol, the following conditions for their synthesis were varied: the amount of the added glycidol, temperature, and duration of synthesis. The influence of these factors on the capacity, selectivity, and efficiency of the resins in the mode of suppressed ion chromatography was studied; in addition, the stationary phases were studied in the mode of hydrophilic interaction liquid chromatography using the Tanaka test. It was shown that the synthesis conditions under study ensure the control of the capacity and selectivity of anion exchangers, while their hydrophilicity changes insignificantly. The behavior of oxoanions on covalently attached resins in the ion chromatography mode was studied for the first time, and the applicability of phases with quaternized polyethyleneimine in the hydrophilic interaction liquid chromatography mode to the separation of sugars, amino acids, water-soluble vitamins, nucleosides, and nitrogenous bases was demonstrated for the first time. [ABSTRACT FROM AUTHOR]

Membrane fouling is a serious issue in membrane technology which cannot be completely avoided but can be diminished. The perspective technique of membrane modification is the introduction of hydrophilic polymers or polyelectrolytes into the coagulation bath during membrane preparation via non-solvent-induced phase separation. The influence of polyacrylic acid (PAA) molecular weight (100,000, 250,000 and 450,000 g·mol−1) added to the aqueous coagulation bath (0.4–2.0 wt.%) on the polysulfone membrane structure, surface roughness, water contact angle and zeta potential of the selective layer, as well as the separation and antifouling performance, was systematically studied. It was found that membranes obtained via the addition of PAA with higher molecular weight feature smaller pore size and porosity, extremely high hydrophilicity and higher values of negative charge of membrane surface. It was shown that the increase in PAA concentration from 0.4 wt.% to 2.0 wt.% for all studied PAA molecular weights yielded a substantial decrease in water contact angle compared with the reference membrane (65 ± 2°) (from 27 ± 2° to 17 ± 2° for PAA with Mn = 100,000 g·mol−1; from 25 ± 2° to 16 ± 2° for PAA with Mn = 250,000 g·mol−1; and from 19 ± 2° to 10 ± 2° for PAA with Mn = 450,000 g·mol−1). An increase in PAA molecular weight from 100,000 to 450,000 g·mol−1 led to a decrease in membrane permeability, an increase in rejection and tailoring excellent antifouling performance in the ultrafiltration of humic acid solutions. The fouling recovery ratio increased from 73% for the reference membrane up to 91%, 100% and 136% for membranes modified with the addition to the coagulation bath of 1.5 wt.% of PAA with molecular weights of 100,000 g·mol−1, 250,000 g·mol−1 and 450,000 g·mol−1, respectively. Overall, the addition of PAA of different molecular weights to the coagulation bath is an efficient tool to adjust membrane separation and antifouling properties for different separation tasks. [ABSTRACT FROM AUTHOR]

Abstract Plasma agriculture is a promising niche of interdisciplinary research where the physics, of non-equilibrium gases meets surface chemistry and biological responses. Despite numerous scientific papers, the interaction of gaseous plasma with seeds is not understood enough to make the technique useful in practical agriculture. An obstacle is an improper methodology adopted by different authors. In this paper, we show that the surface wettability does not depend on discharge parameters such as power and pressure, but rather on the fluence of oxygen atoms onto the seed surface. The proper methodology is demonstrated for the case of corn seeds. The surface activation, which enables improved water uptake or good adhesion of a coating, progresses relatively linearly up to the O-atom fluence of 3 × 1024 m−3 and remains constant thereafter. The minimal water contact angle achievable using oxygen plasma treatment is a few degrees.

This work offers an ecologically friendly and facile approach for the modification of high-tonnage commercial polymers, including polypropylene (PP), high-density polyethylene (HDPE), and poly(ethylene terephthalate) (PET), and preparation of nanocomposite polymeric membranes via incorporation of modifying oligomer hydrophilic additives, such as poly(ethylene glycol) (PEG), poly(propylene glycol) (PPG), polyvinyl alcohol (PVA), and salicylic acid (SA). Structural modification is accomplished via the deformation of polymers in PEG, PPG, and water-ethanol solutions of PVA and SA when mesoporous membranes are loaded with oligomers and target additives. The content of target additives in nanocomposite membranes is controlled by tensile strain, and the level of loading can achieve 35–62 wt.% for PEG and PPG; the content of PVA and SA is controlled by their concentration in the feed solution. This approach allows for the simultaneous incorporation of several additives which are shown to preserve their functional performance in the polymeric membranes and their functionalization. The porosity, morphology, and mechanical characteristics of the prepared membranes were studied. The proposed approach allows an efficient and facile strategy for the surface modification of hydrophobic mesoporous membranes: depending on the nature and content of target additives, their water contact angle can be reduced to 30–65°. Water vapor permeability, gas selectivity, antibacterial, and functional properties of the nanocomposite polymeric membranes were described.

This paper investigates the effect of three different ring electrode configurations (copper wire electrode [CWE], copper foil electrode [CFE], and copper block electrode [CBE]) on the characteristics of the ring–ring typed atmospheric pressure plasma jet (APPJ) and polyethylene terephthalate modification. The characteristics of APPJ were simulated and experimentally explored. The results show that APPJ with CWE has the maximum electric field magnitude, power, concentration of reactive species, and gas temperature. While CBE has the most uniform electric field distribution and the most stable discharge process. Besides, CWE has the maximum hydrophilization rate while the CBE has the most uniform modification area. The plasma characteristics and modification effect of APPJ with CFE fall in between. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new type of oxygen mixing cold plasma jet is developed to modify metal materials. • The plasma jet can treat various metal materials to be superhydrophilic within 20 s. • The high-efficiency plasma treatment does not cause serious structural damages. • Mechanisms leading to the high-efficiency treatment are systematically studied. Engineering metal materials have been widely developed and applied in aviation, aerospace and biomedicine fields. Wettability improvement of these materials can alleviate problems caused by low adhesion and poor bioactivity, thereby facilitating their practical applications. Compared with other methods, atmospheric pressure cold plasma treatment has better versatility and can efficiently improve wettability without causing serious damages, and has therefore been widely used in polymer hydrophilization. However, when treating metal materials, the cold plasma may induce surface breakdown or have low efficiency. In this paper, we developed a new cold plasma jet by mixing oxygen into working gas to achieve high-efficiency and low-damage modification. When oxygen mixing ratio was 0.4 %, the cold plasma jet could modify TC4 titanium alloy surface to be superhydrophilic within 20 s, which was much more efficient than traditional plasma jet (120 s). We then further investigated the mechanism contributing to higher efficiency, and found that the oxygen-mixing plasma jet did not cause serious damages, while generating more polar groups by higher-concentration active particles, as confirmed by surface energy calculation and optical emission spectra. Besides titanium alloy, the oxygen-mixing plasma jet could also achieve rapid hydrophilization of various engineering metal materials, showing promising application prospects. [ABSTRACT FROM AUTHOR]

To increase the permeation performance and antifouling properties of polymer membranes, a one‐step reaction using electron irradiation was developed. This process combines the surface activation of the membrane polymer and the simultaneous permanent immobilization of hydrophilic molecules. This technology can be applied to various polymers, flat sheet/hollow fiber membranes and all pore ranges. The roll‐to‐roll system developed for this enables all process steps including inline analysis for quality control of the membrane surface in a continuously operated system. [ABSTRACT FROM AUTHOR]

This work addresses hydrophilization of hydrophobic mesoporous membranes based on high-density polyethylene (HDPE) via ozonation. Mesoporous HDPE membranes were prepared by intercrystallite environmental crazing. Porosity was 50%, and pore dimensions were below 10 nm. Contact angle of mesoporous membranes increases from 96° (pristine HDPE) to 120° due to the formation of nano/microscale surface relief and enhanced surface roughness. The membranes are impermeable to water (water entry threshold is 250 bar). The prepared membranes were exposed to ozonation and showed a high ozone uptake. After ozonation, the membranes were studied by different physicochemical methods, including DSC, AFM, FTIR spectroscopy, etc. Due to ozonation, wettability of the membranes was improved: their contact angle decreased from 120° down to 60°, and they became permeable to water. AFM micrographs revealed a marked smoothening of the surface relief, and the FTIR spectra indicated the development of new functionalities due to ozonolysis. Both factors contribute to hydrophilization and water permeability of the ozonated HDPE membranes. Hence, ozonation was proved to be a facile and efficient instrument for surface modification of hydrophobic mesoporous HDPE membranes and can also provide their efficient sterilization for biomedical purposes and water treatment.

Plasma agriculture is a promising niche of interdisciplinary research where the physics, of non-equilibrium gases meets surface chemistry and biological responses. Despite numerous scientific papers, the interaction of gaseous plasma with seeds is not understood enough to make the technique useful in practical agriculture. An obstacle is an improper methodology adopted by different authors. In this paper, we show that the surface wettability does not depend on discharge parameters such as power and pressure, but rather on the fluence of oxygen atoms onto the seed surface. The proper methodology is demonstrated for the case of corn seeds. The surface activation, which enables improved water uptake or good adhesion of a coating, progresses relatively linearly up to the O-atom fluence of 3 × 1024 m−3 and remains constant thereafter. The minimal water contact angle achievable using oxygen plasma treatment is a few degrees. [ABSTRACT FROM AUTHOR]

Sirolimus incorporated nonwoven polymer matrices were fabricated via electrospinning. Release kinetics considering different fiber diameters and layer thicknesses were investigated. In vitro drug release profiles were evaluated by measuring the drug concentration in an established drug release medium (0.9% saline solution with additives, not buffered) at predetermined time points. Furthermore, an NH3-plasma pretreatment was examined to ensure complete wetting from the beginning of the study. In comparison to thin drug-loaded PLLA spray coatings it was shown that the release of sirolimus is diffusion- and degradation-controlled regardless of the surface-to-volume ratio, though fiber diameters or a hydrophilization can affect its release kinetics.

This paper studies the influence of lattice and shell type architecture on the mechanical properties of biodegradable polymer scaffolds (cellular matrices) designed to create structures for bone tissue engineering. Varying the topology of nodal connections makes it possible to control the relative rigidity of the metamaterial in the range from 0.004 to 0.123. It is shown to be possible to create permeable scaffolds using thermally extruded 3D printing based on polymers of different elasticities—polylactide and polyurethane. The use of "unit cells" of various types allows fabricating structures such as shells based on polylactide with a compressive strength of 1.5 to 19.7 MPa. Shells with a cubic type architecture based on polyurethane can be almost reversibly deformed at values of deformation of more than 50%. The developed approaches for obtaining polymer metamaterials and modifying their surface with calcium phosphate layer using an artificial interstitial fluid can increase the hydrophilicity of materials. [ABSTRACT FROM AUTHOR]

The impact of the Corona, dielectric barrier discharge, and low pressure radiofrequency air plasmas on the chemical composition and wettability of medical grade polyvinylchloride was investigated. Corona plasma treatment exerted the most pronounced increase in the hydrophilization of polyvinylchloride. The specific energy of adhesion of the pristine and plasma-treated Polyvinylchloride (PVC) tubing is reported. Plasma treatment increased markedly the specific free surface energy of PVC. The kinetics of hydrophobic recovery following plasma treatment was explored. The time evolution of the apparent contact angle under the hydrophobic recovery is satisfactorily described by the exponential fitting. Energy-dispersive X-ray spectroscopy of the chemical composition of the near-surface layers of the plasma-treated catheters revealed their oxidation. The effect of the hydrophobic recovery hardly correlated with oxidation of the polymer surface, which is irreversible and it is reasonably attributed to the bulk mobility of polymer chains. [ABSTRACT FROM AUTHOR]

The intrinsic hydrophobic nature of polymer tubes limits their applications in biomedical and mechanical fields. In this paper, homogeneous hydrophilization on the inner surfaces of polytetrafluoroethylene tubes was realized by directly inserting a flexible atmospheric cold microplasma jet (FμPJ) into the tubes. The water contact angle, surface morphologies, and chemical compositions of the treated inner surfaces were investigated to characterize the plasma hydrophilization. Results demonstrated that the wettability of the inner walls of the tube was well improved and the wettability could be retained at a low value even after 30 days of storage. Notably, homogeneous hydrophilization was achieved along the axial and circumferential directions of the tube. The results indicated that FμPJ shows great potential for uniform inner surface modification of polymers tubes. [ABSTRACT FROM AUTHOR]

Polyhydroxyalkanoates (PHAs) are synthesized by bacteria as an intracellular storage polyester, where PHA synthase (PhaC) catalyzes the polymerization of its substrate hydroxyacyl-coenzyme A (HA-CoA) to form PHA. When PhaC is overexpressed in Escherichia coli , most PhaC protein is produced as insoluble inclusion bodies due to its low aqueous solubility. This study aimed to improve the solubility of Ralstonia eutropha PHA synthase (PhaC Re) by fusing a hydrophilic tag, glutathione S -transferase (GST), to the protein's N-terminus. In in vivo assays, the GST tag had no obvious effect on solubility and enzymatic activity of PhaC Re. However, an in vitro assay revealed that the surface of GST-fused PhaC Re (GST-PhaC Re) had increased hydrophilicity, and tended to form correct PhaC Re dimers when added to the (R)-3-hydroxybutyryl-CoA substrate. Although GST-PhaC Re displayed a long lag phase at the start of a polymerization reaction, granule-associated GST-PhaC Re showed higher catalytic activity than PhaC Re in kinetic analysis. The results are discussed in light of the dimerization mechanisms of PhaC Re. [ABSTRACT FROM AUTHOR]

• Highly stable, water soluble Ag 2 S QDs were prepared using amphiphilic polymer (PMAO). • PLQY after modification dropped only by 40% and was stable for at least 12 months. • Hydrodynamic diameter of water soluble Ag 2 S QDs was about 10 nm. • Cytotoxicity of Ag 2 S QDs water solutions was determined. Development of protocols for transferring of hydrophobic quantum dots (QDs) into aqueous solution is of special importance for their biomedical applications. Particularly, hydrophilization of Ag 2 S without quenching of photoluminescence is a great challenge. Application of standard protocol for amphiphilic polymer coating of hydrophobic Ag 2 S nanocrystals failed, whereas ligand exchange and direct synthesis of Ag 2 S in aqueous solution leads to poorly emitting materials. In this paper we present the facile method for transferring of hydrophobic Ag 2 S QDs into aqueous solution employing the phase transfer catalysed hydrolysis of a commercially available polymer - poly(maleic anhydride- alt -1-octadecene), (PMAO) in the presence of tetramethylammonium hydroxide. Because the original surface ligands are retained and we do not use solvents (like THF) detrimental for Ag 2 S emission, the modification does not deteriorate photoluminescence properties and quantum yield of modified QDs in aqueous solution reaches 60% of that for hydrophobic QDs in chloroform. The hydrodynamic diameter of modified, water soluble Ag 2 S QDs is about 10 nm and is only slightly larger than their original size. Moreover, the polymer coated nanocrystals are not aggregated and are stable for months. Surface characterization of QDs by NMR and IR spectroscopy indicates that polymer chains intercalate alkyl chains of dodecanethiol (DDT) bound to the surface of Ag 2 S. The cytotoxicity studies indicate that the presented method should be regarded as a notable progress towards the biocompatible Ag 2 S NIR-II emitting nanoprobes. [ABSTRACT FROM AUTHOR]

This paper presents a one-step selective separation of polyvinyl chloride (PVC) from PVC/PET mixture based on hydrophilicity building on the PVC surface using H2O2/ultrasonication. After the combined treatment, the decrease of PVC contact angle (from 87.2° to 71.5°) is consistent with the increase in hydrophilic functional groups that is evidenced by Fourier transform infrared and X-ray photoelectron spectroscopy results on the PVC surface. The H2O2/ultrasonic treatment generates oxidizing agent and increases hydrophilicity on the PVC surface, which allows to selectively separate the treated PVC by its submerging on the reactor bottom. Meanwhile, the treated PET is easily floated off because it is not affected by the combined treatment and still maintains the hydrophobic surface. The combined treatment of H2O2 and ultrasonic irrigation obtains 100% purity and recovery of the PVC separation under the optimum conditions. The optimized separation conditions are H2O2 concentration 3%, ultrasonic irrigation time 30 min and temperature 30 °C, floating agent concentration 0.4 mg/L and intermittent mixing at 50 rpm. Reusing of H2O2 is also feasible to save cost and environmental benefits. The combination of ultrasonication and H2O2 is an effective and inexpensive method for PVC separation to improve plastic recycling quality. [ABSTRACT FROM AUTHOR]

The commercial fluorocarbon surfactant (FCS) DuPont™ Zonyl 321 fluorinated cationic surfactants, was employed to modify both flat‐sheet and hollow‐fiber poly(tetrafluoroethylene) (PTFE) porous membranes. The variation of morphology, wettability, and hydrophilicity durability to acid and alkali as well as the filtration performance of both membranes were investigated. Such superhydrophilic membranes showed better wetting stability and higher resistance to acid and alkali solutions. Moreover, both membranes exhibited good filtration performance. [ABSTRACT FROM AUTHOR]

Abstract Nonlinear optical properties of colloidal CdSe quantum dots conjugated with proteins were investigated in a wide spectral range with the two-photon excited emission technique using a tunable femtosecond laser system in the range from 700 to 1000 nm. The most significant value of the two-photon absorption cross section σ 2 for 2.9 nm size hydrophilic CdSe quantum dot was equal to 4 505 GM, while the two-photon excitation action cross section σ 2 ·QY was found to be 0.101 GM at 900 nm. The nonlinear absorption properties are present as appropriate cross sections normalized per molecular weight which allows comparison of the nonlinear properties of the studied quantum dots with various nanosystems or organic dyes. The properties of these proteins covering hydrophilic colloidal quantum dots can be potentially useful for nonlinear bioimaging. Graphical abstract fx1 [ABSTRACT FROM AUTHOR]

The impact of the Corona, dielectric barrier discharge, and low pressure radiofrequency air plasmas on the chemical composition and wettability of medical grade polyvinylchloride was investigated. Corona plasma treatment exerted the most pronounced increase in the hydrophilization of polyvinylchloride. The specific energy of adhesion of the pristine and plasma-treated Polyvinylchloride (PVC) tubing is reported. Plasma treatment increased markedly the specific free surface energy of PVC. The kinetics of hydrophobic recovery following plasma treatment was explored. The time evolution of the apparent contact angle under the hydrophobic recovery is satisfactorily described by the exponential fitting. Energy-dispersive X-ray spectroscopy of the chemical composition of the near-surface layers of the plasma-treated catheters revealed their oxidation. The effect of the hydrophobic recovery hardly correlated with oxidation of the polymer surface, which is irreversible and it is reasonably attributed to the bulk mobility of polymer chains.

Low-toxic and efficient fluorescent core-shell CuInS 2 /ZnS (CIS/ZnS) quantum dots (QDs) are good candidates for optoelectronic device applications. They are synthesized in a hydrophobic environment, while large amounts of organic solvents used in the preparation of fluorescent films have significant problems on environmental load and human health. CIS/ZnS QDs hydrophilized by adsorbing 3-mercaptopropionic acid on their surfaces can be used in the aqueous film fabrication process. In this work, the aqueous electrophoretic deposition (EPD) of the hydrophilized QDs with silicone-modified acrylic resin nanoparticles was performed to fabricate fluorescent nanocomposite films. The hydrophilized QDs and resin nanoparticles were simultaneously dispersed in basic aqueous solutions due to electrostatic repulsion resulting from their negatively charged surfaces. Transparent films were obtained on a transparent conductive substrate at the anode side by the EPD. They showed yellow fluorescence of the QDs. The thickness increased with increasing the deposition time; however, hemispherical holes attributed to oxygen gas generated by water electrolysis were observed at the longer time. The electron microscopy revealed that the films were densely and homogeneously deposited. The QDs were dispersed around the resin nanoparticles without aggregation. The fluorescence (FL) quantum yield was 43%. The optical absorption peak and FL intensity of the QDs increased accompanied by the film growth. The nanocomposite film showed good heat resistance at 80-120 °C for 5 h; therefore, the prepared films have feasibility in white light-emitting diode (LED) applications. A lightening device structured with the obtained EPD film placed on a blue LED successfully emitted white light. In addition, the flexibility of the nanocomposite film was demonstrated. The aqueous EPD method would be one of the suitable methods for the industrial production of fluorescent QD films. This technique can be applied to other hydrophilic fluorescent QDs with charged surfaces. Realization of various fluorescent QD films would expand the application possibilities.

Abstract: Phase diagrams of the polyphenylsulfone (PPSU)-polyethylene glycol (PEG)-N-methyl-2-pyrrolidone (NMP) system have been plotted as a function of PEG molecular weight. For 15 wt % PPSU solutions containing 15 wt % of PEG with molecular weight of 6000-40 000 g mol-1, the occurrence of an upper critical solution temperature (UCST, solution-gel transfer (gel point)) and a lower critical solution temperature (LCST) was found. According to the phase diagrams analysis, a method for the preparation of high flux PPSU membranes using the systems with UCST and LCST in an experimentally attainable temperature range has been proposed. The method involves casting solution processing at a temperature of the existence of a one-phase homogeneous solution (UCST < T < LCST), and the use of a coagulation bath at a temperature between UCST (gel point) and LCST. Membranes prepared from 15 wt % PPSU solutions with the addition of PEG-20000 were found to have the highest pure water flux (500-1000 L m-2 h-1 at 0.1 MPa), and a human serum albumin rejection of ca. 90%. [ABSTRACT FROM AUTHOR]

A novel composite based on hydrophilic boehmite-PVB/PVDF blended membrane- immobilized nanoscale zero-valent iron (nZVI) (BPPN) was synthesized. When the initial concentration of Cr(VI) was 20 mg/L, 100% Cr(VI) was removed by BPPN at an initial pH of 4.08 under room temperature of 25 °C within 90 min. In addition, the reactivity of the regenerated BPPN composites toward Cr(VI) removal were not obviously declined after 6 cycles. The resultant BPPN demonstrated high reactivity, preeminent stability and reusability in the reaction course. Meanwhile, the BPPN composites showed a higher removal efficiency toward the removal of Cr(VI) compared with alumina-PVB/PVDF-nZVI (APPN) composites. The plentiful hydroxyl groups of boehmit on the BPPN surface resulted in the enhancement in hydrophilicity and improved Fe 0 loading of the BPPN composites. For environmental parameters, results indicated that there was a negative effect of increasing the initial concentration or decreasing reaction temperature toward the removal of Cr(VI) by BPPN, and that the acidic and neutral conditions showed more favorable effect on Cr(VI) removal than the alkaline ones. The generated ferrous ions on the surface of BPPN were certified to play an important role in removal of Cr(VI). XPS analysis suggested that the reduction reaction of Cr(VI) occurred on the surface of the composite and produced precipitation of Cr(III). The Cr(VI) removal by BPPN composite was found to follow a revised kinetics well. This study suggests that the novel BPPN composite possessing excellent performance may be a promising functional material of heavy metal wastewater treatment. [ABSTRACT FROM AUTHOR]

We discuss how hydrophobic polyether sulfone hollow fiber membranes could be hydrophilized by surface coating them with natural hydrogel calcium alginate. The outer surface of the hollow fiber membrane was brought into contact with a solution of sodium alginate while calcium chloride solution was held within the lumen of the membrane. The divalent calcium ions diffused through the membrane pores and cross-linked the alginate, which formed a coating layer on the outer surface. The thickness of the calcium alginate layer could be controlled by changing the duration of cross-linking. The coated hollow fiber membrane samples were characterized by transmission electron microscopy (TEM). The increase in surface hydrophilicity was confirmed by water contact angle measurement. The hydraulic permeability of the coated membrane was higher than that of the uncoated membrane. The permeability of model solutes such as dimethyl sulfoxide (DMSO) and antipyrine was similar with both coated and uncoated membranes. Such hydrophilized hollow fiber membranes could potentially be used in membrane bioreactors and as scaffold for tissue engineering. [ABSTRACT FROM AUTHOR]

This study investigated the effect of acid post-treatment on the filtration performance of organosilica membranes. The membranes were prepared from 1,2-bis(triethoxysilyl)ethane (BTESE) via sol-gel processing with different H 2 O/BTESE molar ratios. Fourier-transform infrared spectra significant residual ethoxy groups within membranes derived from sols with low H 2 O/BTESE ratios, after firing at 300 °C in N 2 . The ethoxy groups within the membranes were hydrolyzed to hydroxide groups by immersing the membranes in hydrochloric acid (HCl). This rendered the membranes more hydrophilic. The hydroxyl groups may have promoted the formation of hydrophilic pores, which would in turn promote water permeation. The HCl-treated membranes showed higher water permeability than the original BTESE-derived membrane. The effect of HCl treatment was more pronounced for the membrane prepared with the lowest H 2 O/BTESE ratio of 1, resulting in approximately three times higher water permeability than the original membrane. Membranes prepared from sols with low H 2 O/BTESE ratios showed improved solute rejection and increased water permeability, upon HCl treatment. This was attributed to cross-linking in the organosilica matrix via the condensation of newly-formed hydroxyl groups, that caused the narrowing or blocking of large pores. [ABSTRACT FROM AUTHOR]

It is challenging to achieve long-lasting hydrophilicity by surface modification of polydimethylsiloxane (PDMS), principally due to the hydrophobic recovery that occurs. This involves the migration of low molecular weight species from the bulk to the surface and is driven by the reduction of interfacial free energy. In this study, spontaneous adsorption of poly(vinyl alcohol) was carried out on Sylgard PDMS films and their modified derivatives. PDMS ox1s , PDMS ox60s , and PDMS ox60s+2k were prepared by 1-s oxygen plasma, 60-s oxygen plasma, and 60-s oxygen plasma followed by covalent attachment of linear PDMS of 2 kDa molecular weight on PDMS films, respectively. Surface morphology was characterized by optical and atomic force microscopy and hydrophilicity was monitored by dynamic water contact angle measurements. It was found that negligible PVOH adsorption takes place on PDMS ox60s due to the lack of hydrophobic driving force and that extensive PVOH thin film dewetting on PDMS and PDMS ox1s results in insignificant improvement in hydrophilicity. However, a continuous PVOH thin film albeit with some small holes was obtained on PDMS ox60s+2k . PDMS ox60s+2k -PVOH exhibits advancing and receding contact angles of 80–90°/16 ± 2°, which are significantly lower than 123 ± 5°/97 ± 2° on unmodified PDMS. A range of static contact angles were also measured, some of which are lower than those reported in the literature. The PDMS ox60s+2k -PVOH system demonstrates superior long-term and hydrolytic stability, which are attributed to the removal of the driving force for hydrophobic recovery by inserting a hydrophobic PDMS layer between a hydrophilic, plasma-oxidized, PDMS bulk and a hydrophilic PVOH exterior. This is a new concept in addressing hydrophobic recovery of hydrophilized silicones. The spontaneous nature of the adsorption process and the crystallinity of the PVOH barrier layer are the other advantages demonstrated in this study. [ABSTRACT FROM AUTHOR]

Hydrophilicity and pore uniformity are the key parameters for ultrafiltration (UF) membranes to avoid fouling and ensure separation effectiveness. In this paper, a simple 'green' in-situ chemical reaction assisted phase separation method was studied, in which amine molecules bearing hydrophilic hydroxyl groups were grafted onto polyvinyl chloride (PVC) chains in dissolution process without initiator. The influence of modifier concentration on the structure, separation and anti-fouling performance of the PVC membranes was studied. The results indicated that the robust hydrophilicity, and high pore size uniformity and porosity of were achieved by properly anchoring preferable amine molecules. The pure water flux of the modified membrane was 261.5 L·m−2·h−1, BSA rejection was 99.1 % when 10 wt% SRN was added. Approximately 27 % increase of rejection to BSA, and 10-fold pure water flux that of the pristine PVC membrane. Due to the stable existence of modifiers in the membrane, the improved membrane hydrophilicity was maintained through 320 h filtration and acid/alkali soaking tests. This study provides a simple modification approach to enhance PVC UF membrane hydrophilicity and pore uniformity. [Display omitted] • 'Green' reaction assisted phase inversion for PVC membranes modification was adopted. • Hydrophilicity, pore size uniformity and porosity were simultaneously improved. • 10-fold flux, 27 % BSA rejection, and 55 % anti-fouling ability increase were obtained. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hydrophilization of PC by Fe (VI) was due to surface oxidation and hydrolysis. • The flotability of PC was selectively suppressed from 100.0% to about 0.0%. • Flow rate affected plastic flotation via generating bubbles, not via flow field. • PC was effectively separated by flotation with recovery and purity of 100.0%. Plastic recycling is a promising technology, as it can both contribute to circular economy goals and reducing plastic pollution; however, it faces significant challenges due to the lack of effective separation methods. Herein, we studied the flotation separation of polycarbonate (PC), a major component of plastic waste, from multi-plastic mixtures after hydrophilization by Fe(VI). First, the effect of Fe(VI) treatment on the surface properties of the plastics was studied. Fe(VI) induced hydrophilization of PC, with a decreased contact angle of about 19°; this was attributed to the introduction of hydrophilic moieties by surface oxidation and hydrolysis reactions. Then, the effect of operating conditions in both hydrophilization and flotation on the flotability of plastics was investigated. In both binary and multi-plastic mixtures, hydrophilization selectively suppressed the flotability of PC from 100% to about 0.0%. Numerical simulation was performed using the population balance model of computational fluid dynamics to determine the gas-liquid flows during flotation. It was found that the flow rate affected flotation of plastics via bubble formation rather than flow fields. Finally, the optimization of hydrophilization was performed using the Box Behnken design of response surface methodology. The results showed that PC was separated from multi-plastic mixtures with recovery and purity of 100.0% under the optimum conditions. These results would greatly facilitate the development of plastic recycling. [ABSTRACT FROM AUTHOR]

Poly (vinylidene fluoride) (PVDF) microporous film was successfully synthesized and functionalized by poly acrylic acid (PAA) for immobilization of nanoscale zero-valent iron (NZVI). PAA was innovatively introduced onto PVDF film via in situ polymerization of acrylic acid (AA) and followed by ion exchange procedure. The as-prepared PAA/PVDF-NZVI hybrids (PPN) were characterized in terms of morphology (SEM) and surface functional groups (FTIR). FTIR spectra confirms the functionalization of PVDF film by coating of PAA within its micropores. And SEM images suggested that NZVI were well immobilized onto the surface of the support. Over the reaction course, the resultant PPN hybrids demonstrated high reactivity, excellent stability and reusability for Cr(VI) removal. Results showed that lower pH and initial concentration facilitated the removal of Cr(VI) by PPN. Compared with bare NZVI, PAA/PVDF film-immobilized NZVI resulted in a lower activation energy for Cr(VI) removal, indicating that Cr(VI) reduction process with PPN is a surfacecontrolled chemical reaction. Moreover, a two-parameter pseudo-first-order model was provided and well-described the reaction kinetics of Cr(VI) over PPN under various conditions.

We demonstrate Ullmann-type reactions as novel and advantageous functionalization of carbon nanotubes (CNTs) toward tunable surface chemistry. The functionalization routes comprise O-, N-, and C-arylation of chlorinated CNTs. We confirm the versatility and efficiency of the reaction allowing functionalization degrees up to 3.5 mmol g−1 by applying both various nanotube substrates, i.e., single-wall (SWCNTs) and multi-wall CNTs (MWCNTs) of various chirality, geometry, and morphology as well as diverse Ullmann-type reagents: phenol, aniline, and iodobenzene. The reactivity of nanotubes was correlatable with the nanotube diameter and morphology revealing SWCNTs as the most reactive representatives. We have determined the optimized conditions of this two-step synthetic protocol as: (1) chlorination using iodine trichloride (ICl3), and (2) Ullmann-type reaction in the presence of: copper(I) iodide (CuI), 1,10-phenanthroline as chelating agent and caesium carbonate (Cs2CO3) as base. We have analyzed functionalized CNTs using a variety of techniques, i.e., scanning and transmission electron microscopy, energy dispersive spectroscopy, thermogravimetry, comprehensive Raman spectroscopy, and X-ray photoelectron spectroscopy. The analyses confirmed the purely covalent nature of those modifications at all stages. Eventually, we have proved the elaborated protocol as exceptionally tunable since it enabled us: (a) to synthesize superhydrophilic films from—the intrinsically hydrophobic—vertically aligned MWCNT arrays and (b) to produce printable highly electroconductive pastes of enhanced characteristics—as compared for non-modified and otherwise modified MWCNTs—for textronics.

Materials of relevance in Printed circuit board (PCB) technology such as FR4, polyimides, and imide-based photosensitive dry films are being currently implemented for the fabrication of microfluidic devices integrated on PCB with electric circuitry and sensors. In this work, methods for efficient and stable in time hydrophilization of these substrates were developed to promote microchannel filling and prevent protein or other biomolecule adsorption. Well-established and easy to implement methods such as plasma etching and PEG coatings were explored. The wettability of the modified surfaces was probed as a function of time after surface hydrophilization by means of water contact angle measurements, while assessment of protein adsorption was implemented as a means to investigate the presence of protein-repellent PEG coatings. Surface superhydrophilization with extreme stability over time at room and elevated temperatures was demonstrated on plasma micro nanotextured polyimide surfaces, retained for up to 80 days. FR4 and photosensitive imide-based dry film surfaces were hydrophilized with stable in time PEG-silane coatings, also retaining their hydrophilicity at elevated temperatures. Furthermore, they were most successfully (super)hydrophilized with UV-assisted PEG coatings, also proven stable in time and at elevated temperatures. Finally, capillary pumping was demonstrated on open microchannels created on FR4 with optimal coatings. [ABSTRACT FROM AUTHOR]

In this paper, experimental results are presented on the deposition of colloidal gold nanoparticles on the surfaces of TiO2 prepared on silicon/silicon dioxide. Important procedures, such as titanium dioxide surface hydrophilization as well as functionalization by an organosilane coupling agent (3-aminopropyl) trimethoxysilane and (3-mercaptopropyl) trimethoxysi-lane were investigated in order to obtain a metal oxide surface with the most convenient properties for immobilization of gold nanoparticles having a dense and uniform distribution. TiO2 nanotips prepared by reactive ion etching of oxide surface covered with self-mask gold nanoparticles are demonstrated. [ABSTRACT FROM AUTHOR]

Biodegradable electrospun sponges are of interest for various applications including tissue engineering, drug release, dental therapy, plant protection, and plant fertilization. Biodegradable electrospun poly(l-lactide)/poly(ε-caprolactone) (PLLA/PCL) blend fiber-based sponge with hierarchical pore structure is inherently hydrophobic, which is disadvantageous for application in tissue engineering, fertilization, and drug delivery. Contact angles and model studies for staining with a hydrophilic dye for untreated, plasma-treated, and surfactant-treated PLLA/PCL sponges are reported. Thorough hydrophilization of PLLA/PCL sponges is found only with surfactant-treated sponges. The MTT assay on the leachates from the sponges does not indicate any cell incompatibility. Furthermore, the cell proliferation and penetration of the hydrophilized sponges are verified by in vitro cell culture studies using MG63 and human fibroblast cells., (© 2023 The Authors. Macromolecular Bioscience published by Wiley-VCH GmbH.)

The catalytic properties of penicillin G acylase (PGA) from Escherichia coli in kinetically controlled synthesis of β-lactam antibiotics are negatively affected upon immobilization on hydrophobic acrylic carriers. Two strategies have been here pursued to improve the synthetic performance of PGA immobilized on epoxy-activated acrylic carriers. First, an aldehyde-based spacer was inserted on the carrier surface by glutaraldehyde activation (immobilization yield = 50%). The resulting 3-fold higher synthesis/hydrolysis ratio (vs/vh1 = 9.7 ± 0.7 and 10.9 ± 0.7 for Eupergit® C and Sepabeads® EC-EP, respectively) with respect to the unmodified support (vs/vh1 = 3.3 ± 0.4) was ascribed to a facilitated diffusion of substrates and products as a result of the increased distance between the enzyme and the carrier surface. A second series of catalysts was prepared by direct immobilization of PGA on epoxy-activated acrylic carriers (Eupergit® C), followed by quenching of oxiranes not involved in the binding with the protein with different nucleophiles (amino acids, amines, amino alcohols, thiols and amino thiols). In most cases, this derivatization increased the synthesis/hydrolysis ratio with respect to the non derivatized carrier. Particularly, post-immobilization treatment with cysteine resulted in about 2.5-fold higher vs/vh1 compared to the untreated biocatalyst, although the immobilization yield decreased from 70% (untreated Eupergit® C) to 20%. Glutaraldehyde- and cysteine-treated Eupergit® C catalyzed the synthesis of cefazolin in 88% (±0.9) and 87% (±1.6) conversion, respectively, whereas untreated Eupergit® C afforded this antibiotic in 79% (±1.2) conversion.