Casting Polymer Solution Research Articles

Tuning the selectivity of thin film composite forward osmosis membranes: Effect of co-solvent and different interfacial polymerization synthesis routes

The selectivity of thin film composite membranes supported by a sulfonated polyetheretherketone (sPEEK) hydrophilized polyethersulfone (PES) layer was enhanced by introducing a more volatile co-solvent, i.e. tetrahydrofuran (THF), and by using an alternative simplified preparation method (SIM), which combines the coagulation step of the phase inversion process and the impregnation of the amine monomer of the interfacial polymerization process. The addition of THF to the polymer casting solutions produced TFC membranes with higher retention but lower permeance. The lowest structural parameter (~383 µm) was found for the TFC membrane with a 10% sPEEK – 10% THF support and led to water fluxes of 23 LMH in PRO mode and 11 LMH in FO mode using a DI water feed solution and a 0.5 M NaCl draw solution. A minimal membrane bottom surface porosity was necessary to accomplish satisfying water fluxes in FO. The SIM method resulted in TFC membranes with comparable selectivity but significantly higher permeance and smoother polyamide selective layers.

Low-surface-energy monomer for ultrathin silicone membrane fabrication: Towards enhanced ethanol/water pervaporation performance

Silicone-based polymers are the most popular materials to prepare pervaporation (PV) membranes for bioethanol recovery from fermentation process. However, the existing silicone composite membranes mostly exhibited limited permeance for ethanol/water separation, which can be attributed to the thick active silicone layers resulting from insufficient spreading of the polymer casting solution on the porous substrate. In the present study, we propose the use of low-surface-energy monomer into casting solution to enhance its spreading ability for ultrathin silicone membrane fabrication. In specific, a poly(dimethyldiethoxylsilane) (PDMDES) casting solution was prepared by limited polymerization of its low-surface-energy monomer dimethyldiethoxylsilane (DMDES), and was then casted on a porous substrate. We show that the surface energy of the partially polymerized casting solution maintained low, and an ultrathin PDMDES active layer with thickness of sub-micrometer size was obtained. The physicochemical properties of the PDMDES membrane were further characterized by ATR-FTIR, XRD and TGA, respectively. Upon optimized preparation and operation conditions, the PDMDES composite membrane exhibited a superior flux of 7565.6 g·m−2·h−1, while maintained a comparable separation factor when compared to traditional PDMS membranes. Our strategy provides new insights into the development of ultrathin silicone membranes for enhanced bioethanol recovery.

High molecular weight poly(vinyl pyrrolidone) induces hierarchical surface morphology in poly(vinylidene fluoride) membrane and facilitates separation of oil-water emulsions

Preparation of membranes with hierarchical surface morphology without delaying phase inversion process or increasing time lag between casting and contacting to non-solvent bath is reported. Poly(vinylpyrrolidone) (PVP) acts as a pore forming polymer in membrane preparation via the non-solvent induced phase inversion process. Herein, we report that molecular weight (Mn) of PVP greatly influences the surface morphology of poly(vinylidene fluoride) (PVDF) membrane. PVP of Mn ≥ 360 kDa induces hierarchical globular morphology on PVDF/poly[(methyl methacrylate)-co-(vinylbenzyl chloride)] copolymer membrane, without delaying phase inversion process or increasing time lag between casting of polymer solution and contacting to non-solvent. PVP (Mn ≥360 kDa) exhibited sole effect on the morphology, which did not depend on presence or absence of copolymer nor on the Mn of PVDF. Post modification of the blend membrane with polyethyleneimine gave superhydrophilic and underwater oleophobic membrane. The membrane could separate surfactant-free and surfactant-stabilized oil-water emulsions under applied pressure of 0.35 bar without need of frequent cleaning. A permeate water flux of about 250 L m−2 h−1 with > 99% rejection of oil and flux recovery ratio as high as > 99% was achieved. The membrane modules also showed similar antifouling property during oil-water separation to that of membrane coupons. PVDF/copolymer undergoes nano-phase separation in the casting solution in presence of PVP (Mn ≥360 kDa), formed nano-clusters which remained on the membrane surface. Novel effect of PVP on the surface morphology in continuous-mode membrane preparation, easy post modification, and low flux reduction (15–25%) during separation of oil-water emulsions highlight the potential of the membrane in practical applications.

Quinoid-Resonant Conducting Polymers Achieve High Electrical Conductivity over 4000 S cm-1 for Thermoelectrics.

New conducting polymers polythieno[3,4‐b]thiophene‐Tosylate (PTbT‐Tos) are prepared by solution casting polymerization. Through tuning the alkyl group of TbT, the electrical conductivity can be effectively enhanced from 0.0001 to 450 S cm−1. Interestingly, the electrical conductivity of PTbT‐C1‐Tos increases significantly from 450 S cm−1 at room temperature to 4444 S cm−1 at 370 K, which is disparate from polyethylenedioxythiophene‐Tos exhibiting metallic conducting behavior. Quasi‐reversible phase transformation with temperature from 3D crystallites to lamellar‐stacking coincides with the increasing electrical conductivity of PTbT‐C1‐Tos with heating. Methyl‐substituted PTbT‐Tos with the best electrical property is further utilized for thermoelectrics and a power factor as high as 263 µW m−1 K−1 is obtained. It is believed that PTbT‐Tos will be a promising family of conducting polymers for solution‐processed organic electronics.

Thickness‐dependent microstructural and electromechanical properties in polyurethane films obtained by polymer solution casting

ABSTRACTElectroactive polymers (EAPs) are promising materials for actuation and energy harvesting applications. Among the EAPs, polyurethane (PU) material is of considerable interest given its high values of deformation under an electric field. The electromechanical properties were found to be dependent on the processing technique and the thickness of the film. To understand this relationship, a comprehensive study was carried out on polyether‐based thermoplastic PU elastomer films elaborated by solution casting with thicknesses between 12 and 220 μm. Microstructural, dielectric, mechanical, and electrostriction studies were conducted. Thin films present a lower strain for a given electric field compared to thick films. The films exhibit a structural gradient along the thickness direction: a fast evaporation in the upper part of the film close to the interface with air inhibits the phase separation but a more favored one in the lower part. This is consistent with the modeling based on the gradient of dielectric constant and the experimental, mechanical, and dielectric characterizations. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 46981.

Effect of the supporting layer structures on antifouling properties of forward osmosis membranes in AL-DS mode

Effect of the supporting layer structures on antifouling properties of forward osmosis (FO) membranes in active-layer-facing-draw-solution (AL-DS) mode was investigated through a series of polyketone (PK) membranes prepared by controlling the concentration of the polymer casting solution, initial casting height, and solvent system. A double-skinned FO membrane was prepared by interfacial polymerization on the bottom surface of the PK membrane. The surface pore sizes, bulk porosities, water permeability and alginic acid sodium salt rejection properties of the prepared PK membranes were determined, and the surface roughness, membrane thickness, pure water permeability, salt permeability and FO performance of the PK-based FO membranes were characterized. The alginic acid sodium salt was used to evaluate the antifouling properties of the FO membranes in AL-DS mode. The effect of surface roughness (or surface pore size), membrane thickness, and structural parameter (S value) on the membrane fouling was investigated. The results indicate that decreasing both the surface pore size of the supporting layer and the membrane thickness effectively improves the membrane performance; that is, the membrane possesses both enhanced antifouling properties and water permeability. This work provides firm guidelines for the design of proper supporting layer structures for FO membranes with high performance in AL-DS (or pressure retarded osmosis, PRO) mode.

Surface Characterization by X–Ray Photoelectron Spectroscopy of Polyethersulfone Hollow Fiber Membranes Modified with Surface Modifying Macromolecules

Novel charged–surface modifying macromolecules (cSMMs) were synthesized and incorporated into polyethersulfone(PES) hollow fiber membranes for water separation application. The macromolecules were synthesized with diisocynate, polypropylene oxide and poly(ethylene glycol)–hydroxybenzene sulfonate (PEG–HBS). In this study, the surface of polyethersulfone hollow fiber membranes prepared by the phase inversion method was modified using 1 wt.% of SMM and 22 wt.% PES concentration in the polymer casting solution. The effect of cSMM on PES hollow fiber membrane modification was investigated. Elemental analysis shows enrichment of oxygen and sulfone on the modified PES membrane bulk properties. In addition, the glass transition temperature confirms the miscibility of the cSMM in PES. Important relations between surface characteristics due to SMM modification with the PES membrane for water separation performance with respect to XPS characterization also highlighted.

PEDOT electrodes for triboelectric generator devices

Abstract Triboelectric generators (TEGs) are devices that convert mechanical energy to electrical energy through triboelectric charging of different material surfaces at periodic contact. Typically, such devices consist of two dielectric contacting layers with electrodes attached on the non-contacting sides but alternatively, one material can simultaneously serve as both a contacting and an electrode material. In this work, we report the use of poly(3,4-ethylenedioxythiophene) (PEDOT) for TEG device were PEDOT film serves as both a contacting surface to PDMS and as an electrode. Two different PEDOT films were prepared on glass substrates by vapour-phase polymerization (VPP) and VPP combined with electropolymerization method and compared as TEG electrodes. Additionally, PEDOT/poly(1,6-hexanediol-co-citric acid) (PHC) composite films were prepared by using solution casting polymerization. These methods yielded PEDOT films with different morphology, surface roughness and conductivity. Best performance was demonstrated for the PEDOT film with the lowest surface roughness (1.88 nm RMS), prepared by VPP method, which generated peak current of 0.45 mA/m2 and power density of 95 W/m2, outperforming Sn doped In2O3 electrode approximately by threefold in the same experimental setup.

Internal cross-linked anion exchange membranes with improved dimensional stability for electrodialysis

Anion exchange membranes (AEMs) with a high ion exchange capacity, striking water uptake and excellent dimensional stability were prepared via an internal crosslinking networks strategy. Internal crosslinking networks were formed by reacting 4,4′-bipyridine with brominated poly (2,6-dimethyl-1,4-phenylene oxide) (BPPO). 4,4′-bipyridine not only provides a functional group but also comprises a cross-linking agent without requirements of post-functionalization. The variation of the 4,4′-bipyridine amount into the casting polymer solution was explored to regulate the performance of the anion exchange membranes, and the membrane properties were evaluated by AFM, ion exchange capacity (IEC), water uptake, the linear expansion ratio, tensile strength, thermal stability, membrane area resistance and electrodialysis experiments, etc. The results showed that the cross-linked membrane with the IEC of 1.98mmol/g has much more outstanding dimensional stability (water uptake: 11.68%; swelling ratio: 3.8%) than non-cross-linked BPPO-Tri membrane (water uptake: 53.26%; swelling ratio: 7.71%) and commercial Neosepta AMX membrane (water uptake: 60.29%; swelling ratio: 5.08%), at the high temperature (50°C). When being applied in ED application, the cross-linked BPPO-20 membrane (NaCl remove: 59.7%; energy consumption: 5.97kWh/kg NaCl) exhibits slightly higher desalination efficiency and lower energy consumption than commercial Neosepta AMX membrane (NaCl remove: 58.3%; energy consumption: 6.51kWh/kg NaCl), suggesting its promising application in ED.

Positively charged nanofiltration membrane fabricated by poly(acid–base) complexing effect induced phase inversion method for heavy metal removal

Abstract Poly(arylene ether ketone)s with carboxylic groups (PAEK-COOH) is a good membrane fabrication material, a kind of polyacids, while polyethylenimine (PEI) is a weak organic base, a kind of polybases. Those polyacids and polybases would form ionic complexation at the interface of two liquid phases. In this paper, PAEK-COOH/ N -methyl pyrrolidone (NMP)/1,4-dioxane (DO) mixture, employed as polymer casting solution and aqueous solution of PEI, used as coagulation bath, respectively. Then ion complexation induced phase inversion process is applied to prepare positively charged nanofiltration membrane with thinner but denser separation skin layer. The complexing reaction at the interface of two liquid phases has great influence on the kinetic aspects of phase inversion process, which in accordance would affect the morphology and performance of the membrane. The obtained membrane, fabricated via the ion complexation induced phase inversion method, is positively charged, has high water permeability, and possesses high rejection towards divalent cations, such as Mg 2 + , Ca 2 + , Pb 2 + etc. , which could be used for removal of heavy metals from polluted water. At the optimal condition, the pure water flux of the PAEK-COOH-PEI nanofiltration membrane is 24.3 L·m − 2 ·h − 1 , with MgCl 2 rejection of 92.2%.

The influence of nano‐silica on properties of sulfonated polystyrene‐lignosulfonate membranes as proton exchange membranes for direct methanol fuel cell application

AbstractThe membranes of sulfonated polystyrene, lignosulfonate and nano‐silica (SPS‐LS‐SiO2) that contain different percentages of nano‐silica (1%–5% [w/w]) were prepared and characterized for polymer electrolyte membrane fuel cell (PEMFC). Nano‐silica is an inorganic compound with a surface area of 200 m2/g, and it has a hygroscopic property so that the presence of nano‐silica in membrane can increase properties of membrane. The SPS‐LS‐SO2 membranes were prepared by casting polymer solution and membranes were characterized by functional groups analysis, water uptake, ion exchange capacity (IEC), proton conductivity, methanol permeability, thermal stability, mechanical properties, and surface morphology. The results show the increase of nano‐silica composition in SPS‐LS‐SiO2 membranes, the IEC, water uptake, proton conductivity increase, but a pore size of membrane decreases. On the other hand, it can maintain the mechanical strength of membranes. The SPS‐LS‐SiO2 membranes with nano‐silica composition of 2%–5% (w/w) have the same properties with Nafion®117, especially in proton conductivity at the same treatment and measurement conditions, and its methanol permeability is about 28%–35% smaller than that of Nafion®117 (2.09 × 10−6 cm2/s), so this SPS‐LS‐SiO2 membrane could be used as a polymer electrolyte membrane for direct methanol fuel cell (DMFC) application.

In situ surface crosslinked tight ultrafiltration membrane prepared by one-step chemical reaction-involved phase inversion process between activated PAEK-COOH and PEI

Carboxylated cardo poly(arylene ether ketone)s (PAEK-COOH) is a thermally stable and hydrophilic membrane fabrication material. Herein, PAEK-COOH was employed as membrane material, being dissolved in N-methyl-2-pyrrolidone (NMP) and 1,4-dioxane (DO) mixed solvent and activated by adding 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) to prepare polymer casting solution. Then the activated polymer film was immersed into polyethylenimine (PEI) aqueous solution that served as coagulation bath for taking the one-step chemical reaction-involved phase inversion process. As illustrated by the SEM images, the fabricated crosslinked tight ultrafiltration membrane had a dense and integrally skinned separation skin layer. Chemical composition and hydrophilicity of membrane surface were studied by ATR-FTIR and water contact angle, respectively. Those results revealed that, via the in situ crosslinking of activated carboxylic acid group and PEI along with the phase inversion process, the PEI molecules had been covalently bonded onto membrane surface and resulted in the increase of membrane hydrophilicity. The optimized membrane had a molecular weight cut off (MWCO) of 12.7kDa and an isoelectric point of 7.4, indicating which is slightly positively charged. The one-step chemical reaction involved phase inversion between reactive macromolecules, i.e., activated PAEK-COOH original polymer film and PEI crosslinker in coagulant, was an efficient and convenient approach for fabrication of highly permeable and selective tight ultrafiltration membranes. Membrane had a dye solution permeability of 80–84Lm−2h−1bar−1 and Congo red (CR) rejection of 99.9% in 100h long-term filtration testing, being capable for dye removal from textile wastewater.

Roll type conducting polymer legs for rigid-flexible thermoelectric generator

A roll-type conducting polymer film was explored as a flexible organic p-type thermoelectric leg using poly(3,4-ethylenedioxythiophene) (PEDOT) doped with tosylate. The PEDOT films were prepared through solution casting polymerization and rolled up for a roll-type leg. Due to the high flexibility, the roll-type PEDOT leg enabled easy contact to both top and bottom electrodes. Simulation on the dynamic heat transfer and convective cooling for a vertically roosted rod- and roll-type PEDOT leg showed that the temperature difference (ΔT) between the hot and cold sides of the leg was much higher in the roll than that of the rod. The PEDOT legs were integrated with n-type Bi2Te3 blocks, to give a 36-couple rigid-flexible thermoelectric generator (RF-TEG). The maximum output voltage from the 36-couple RF-TEG under a ΔT of 7.9 K was determined as 36.7 mV along with a high output power of 115 nW. A wearable RF-TEG was prepared upon the combination of the 36-couple RF-TEG with an arm warmer, to afford an output voltage of 10.6 mV, which was generated constantly and steadily from human wrist heat.

PH-sensitive films containing anthocyanins extracted from black bean seed coat and red cabbage

The aim of this study was to develop pH-sensitive films based on corn starch and anthocyanins extracted from black bean seed coat and red cabbage. The pH-sensitive films were developed from solvent casting of polymer solutions containing corn starch, glycerol, and anthocyanin extract (from red cabbage or black bean) prepared at pH 5. The color of films changed from pink to purple and blue, as a function of the pH. The pH-sensitive films were evaluated by their morphological, chemical, physical, mechanical and thermal properties. In addition, the stability was evaluated during 28 days of storage (presence and absence of light; with and without cooling). The pH-sensitive films with red cabbage anthocyanins showed a higher stability than that with black bean anthocyanins when stored at room temperature and exposed to light. Both pH-sensitive films exhibited greater color stability when stored under refrigeration as compared to storage at room temperature.

Microneedles with Controlled Bubble Sizes and Drug Distributions for Efficient Transdermal Drug Delivery.

Drug loaded dissolving microneedles (DMNs) fabricated with water soluble polymers have received increasing attentions as a safe and efficient transdermal drug delivery system. Usually, to reach a high drug delivery efficiency, an ideal drug distribution is gathering more drugs in the tip or the top part of DMNs. In this work, we introduce an easy and new method to introduce a bubble with controlled size into the body of DMNs. The introduction of bubbles can prevent the drug diffusion into the whole body of the MNs. The heights of the bubbles are well controlled from 75 μm to 400 μm just by changing the mass concentrations of polymer casting solution from 30 wt% to 10 wt%. The drug-loaded bubble MNs show reliable mechanical properties and successful insertion into the skins. For the MNs prepared from 15 wt% PVA solution, bubble MNs achieve over 80% of drug delivery efficiency in 20 seconds, which is only 10% for the traditional solid MNs. Additionally, the bubble microstructures in the MNs are also demonstrated to be consistent and identical regardless the extension of MN arrays. These scalable bubble MNs may be a promising carrier for the transdermal delivery of various pharmaceuticals.

Low-Band-Gap Polymer-Based Ambipolar Transistors and Inverters Fabricated Using a Flow-Coating Method

The performances of organic thin film transistors (OTFTs) produced by polymer solution casting are tightly correlated with the morphology and chain-ordering of semiconducting polymer layers, which depends on the processing conditions applied. The slow evaporation of a high boiling point (bp) solvent permits sufficient time for the assembly of polymer chains during the process, resulting in improving the film crystallinity and inducing favorable polymer chain orientations for charge transport. The use of high bp solvents, however, often results in dewetting of thin films formed on hydrophobic surfaces, such as the commonly used octadecyltrichlorosilane (ODTS)-treated SiO2 gate dielectric. Dewetting hampers the formation of uniform and highly crystalline semiconducting active channel layers. In this manuscript, we demonstrated the formation of highly crystalline dithienothienyl diketopyrrolopyrrole (TT-DPP)-based polymer films using a flow-coating method to enable the fabrication of ambipolar transistors and inverters. Importantly, unlike conventional spin-coating methods, the flow-coating method allowed us to use high bp solvents, even on a hydrophobic surface, and minimized the polymer solution waste. The crystalline orientations of the TT-DPP-based polymers were tuned depending on the solvent used (four different bp solvents were tested) and the employment of a thermal annealing step. The use of high bp solvents and thermal annealing of the polymer films significantly enhanced the crystalline microstructures in the flow-coated films, resulting in considerable carrier mobility increase in the OTFTs compared to the spin-coated films. Our simple, inexpensive, and scalable flow-coating method, for the first time employed in printing semiconducting polymers, presents a significant step toward optimizing the electrical performances of organic ambipolar transistors through organic semiconducting layer film crystallinity engineering.

Polyethersulfone/polyacrylonitrile blended ultrafiltration membranes: preparation, morphology and filtration properties.

Polyethersulfone (PES)/polyacrylonitrile (PAN) membranes have been paid attention among membrane research subjects. However, very few studies are included in the literature. In our study, asymmetric ultrafiltration (UF) membranes were prepared from blends of PES/PAN with phase inversion method using water as coagulation bath. Polyvinylpyrrolidone (PVP) with Mw of 10,000 Da was used as pore former agent. N,N-dimethylformamide was used as solvent. The effects of different percentage of PVP and PES/PAN composition on morphology and water filtration properties were investigated. Membrane performances were examined using pure water and lake water filtration studies. Performances of pure water were less with the addition of PAN into the PES polymer casting solutions. However, long-term water filtration tests showed that PES/PAN blend membranes anti-fouling properties were much higher than the neat PES membranes. The contact angles of PES/PAN membranes were lower than neat PES membranes because of PAN addition in PES polymer casting solutions. Furthermore, it was found that PES/PAN blend UF membranes' dynamic mechanical analysis properties in terms of Young's modules were less than neat PES membrane because of decreasing amount of PES polymer.

In‐situ cross‐linked PVDF membranes with enhanced mechanical durability for vacuum membrane distillation

A novel and effective one‐step method has been demonstrated to fabricate cross‐linked polyvinylidene fluoride (PVDF) membranes with better mechanical properties and flux for seawater desalination via vacuum membrane distillation (VMD). This method involves the addition of two functional nonsolvent additives; namely, water and ethylenediamine (EDA), into the polymer casting solution. The former acts as a pore forming agent, while the latter performs as a cross‐linking inducer. The incorporation of water tends to increase membrane flux via increasing porosity and pore size but sacrifices membrane mechanical properties. Conversely, the presence of EDA enhances membrane mechanical properties through in‐situ cross‐linking reaction. Therefore, by synergistically combining the effects of both functional additives, the resultant PVDF membranes have shown good MD performance and mechanical properties simultaneously. The parameters that affect the cross‐link reaction and membrane mechanical properties such as reaction duration and EDA concentration have been systematically studied. The membranes cast from an optimal reaction condition comprising 0.8 wt % EDA and 3‐hour reaction not only shows a 40% enhancement in membrane Young's Modulus compared to the one without EDA but also achieves a good VMD flux of 43.6 L/m2‐h at 60°C. This study may open up a totally new approach to design next‐generation high performance MD membranes. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4013–4022, 2016

Smart photo-induced silicone/TiO2 nanocomposites with dominant [110] exposed surfaces for self-cleaning foul-release coatings of ship hulls

The remarkable surface properties and favorable environmental effects of non-stick, silicone-based, and fouling release (FR) coatings have supported their economic and ecological applications in the marine shipping industry since organotin compounds have been banned. A novel series of solar light-boosted nanocomposites was prepared and characterized, and these materials were applied as a modern stream for ship hull FR technology in field. The design of eco-friendly, ultraviolet visible (UV–vis) smart, silicone-enriched, spherical TiO2 nanocomposites for maritime navigation applications was demonstrated. Rutile TiO2 photonanospheres with dominant [110] facets were synthesized and controlled through the sol–gel technique. Different nanofiller concentrations were blended in silicone nanocomposites through polymer solution casting for comparative purposes. The single-crystal TiO2 photonanofiller enrichment of vinyl-terminated polydimethylsiloxane matrix enhanced photocatalytic activity, a feature that is significant in designing solar-spectrum-boosted self-cleaning surfaces. These investigations revealed that the well-dispersed polymer matrix/photonanofillers influenced the surface wettability, chemical properties, and mechanical features of the prepared FR nanocomposites. The nanocomposites exhibited the best self-cleaning performance at 0.5% nanofillers after UV–vis irradiation. Biological assessments involving a one-month laboratory assay of bacterial and yeast species and a 12-month natural seawater field trial revealed that the modeled nanocomposites exerted a marked photobactericidal effect.

Fabrication and performance of PET mesh enhanced cellulose acetate membranes for forward osmosis

Polyethylene terephthalate mesh (PET) enhanced cellulose acetate membranes were fabricated via a phase inversion process. The membrane fabrication parameters that may affect the membrane performance were systematically evaluated including the concentration and temperature of the casting polymer solution and the temperature and time of the evaporation, coagulation and annealing processes. The water permeability and reverse salt flux were measured in forward osmosis (FO) mode for determination of the optimal membrane fabrication conditions. The optimal FO membrane shows a typical asymmetric sandwich structure with a mean thickness of about 148.2μm. The performance of the optimal FO membrane was tested using 0.2mol/L NaCl as the feed solution and 1.5mol/L glucose as the draw solution. The membrane displayed a water flux of 3.47L/(m2·hr) and salt rejection of 95.48% in FO mode. While in pressure retarded osmosis (PRO) mode, the water flux was 4.74L/(m2·hr) and salt rejection 96.03%. The high ratio of water flux in FO mode to that in PRO mode indicates that the fabricated membrane has a lower degree of internal concentration polarization than comparable membranes.