Non-solvent Induced Phase Separation Research Articles

Mixed-matrix membrane designed with water channels and sieving effect for effective removal of heavy metals

The challenge of eliminating heavy metal ions from water has been addressed using Polysulfone (PSf) membranes, which have demonstrated significant potential in treating contaminated solutions. This research aimed to improve the permeability and separation performance of PSf membranes by incorporating Al2SiO6 into their structure. The introduction of Al2SiO6 into the membrane matrix was achieved through the nonsolvent-induced phase separation (NIPS). The resulting mixed-matrix membrane (MMM) exhibited improved efficiency in water filtration. The inclusion of Al2SiO6 led to desirable changes in membrane properties such as hydrophilicity, contact angle and porosity, thereby enhancing the performance of heavy metal ion removal capability. Under a pressure of 2 bar, the mixed matrix membranes achieved rejections exceeding 95 % for lead and 70 % for arsenic. Furthermore, the occurrence of Al2SiO6 enhanced the anti-fouling assets of the PSf membrane by increasing its hydrophilic nature and facilitating the development of a hydration layer, which tends to prevent the interactions between the membrane surface and foulant. These properties make these membranes suitable candidates for separating toxic ions from water.

Asymmetric PDMS/PVDF Pervaporation Membrane for Separation of Ethanol/Water System

AbstractPreparing asymmetric pervaporation membranes is a kind of promising method to enhance pervaporation membrane flux. Hydrophobic PVDF polymer can be used to prepare asymmetric pervaporation membranes, but its separation factor is relatively low. In this work, to improve the performance of PVDF membrane pervaporation, PDMS polymer was added to the PVDF membrane, and asymmetric PDMS/PVDF permeable membranes were prepared by the non‐solvent induced phase separation (NIPS) method. The effects of mass ratios of PDMS to PVDF on the membrane structures and the membrane properties were characterized by SEM, XRD, FTIR, TGA, water contact angle and mechanical strength. The results showed that the ratios of the PDMS: PVDF affect its phase‐separation behavior. As the addition of PDMS increased, the finger‐like pores on the membrane section gradually became longer, the upper surface changed from less porous to porous structure, and the lower surface structure changed from interconnected flocculent structure to porous, and the best structure of the blend membrane was achieved when the PDMS: PVDF mass ratio was 1 : 5. Therefore, the membrane had the best separation performance in separating 15 wt. % ethanol aqueous solution with a permeate total flux of 273.65 g/(m2 h) and a separation factor of 9.09 when the mass ratio of PDMS: PVDF was 1 : 5.

In situ conversion of ZnO to ZIF-8 in polyimide for ultra-high permeance organic solvent nanofiltration mixed matrix membranes

Mixed matrix membranes (MMMs) incorporating ZIF-8 nanoparticles through non-solvent induced phase separation (NIPS) hold great potential in the organic solvent nanofiltration (OSN) field, but their advancement and application have been significantly hindered by ZIF-8’s instability of ZIF-8 in aqueous conditions and major interfacial incompatibilities with polymers. This study presents an approach to overcome these obstacles by initially forming crosslinked ZnO/polyimide (PI) MMMs via NIPS and crosslinking processes, followed by in-situ conversion of ZnO to ZIF-8 within the membrane structure. This method prevents direct contact of ZIF-8 with water, optimizes the interface between ZIF-8 and the polymer, and modulates the pore structure of the membranes. The resulting crosslinked ZIF-8/PI membranes exhibit an ultra-high ethanol permeance of 42.7 L m⁻2 h⁻1 bar⁻1 and a 99.5 % rejection of Rose Bengal dye, surpassing the performance of all state-of-the-art OSN MMMs to our knowledge. Additionally, these membranes also demonstrate excellent separation performance in harsh solvents such as DMF and NMP. The findings of this study not only significantly advance the development of OSN membranes but also offer insights into the optimization of membrane fabrication techniques, setting a new benchmark for the design of high-performance OSN membranes.

One-Step Phase Separation and Mineralization Fabrication of Membranes for Oily Wastewater Treatment.

Oily wastewater threatens the environment and the human health. Membrane technology offers a simple and efficient alternative to separating oil and water. However, complex membrane modifications are usually employed to optimize the separation performance. In this research, we develop an extremely simple one-step method to in situ calcium carbonate (CaCO3) nanoparticles onto a porous polyketone (PK) membrane via a nonsolvent induced phase separation (NIPS)-mineralization strategy. We utilized the unique chemical property of PK, which allows it to dissolve in a resorcinol aqueous solution. PK was mixed with tannic acid (TA) and calcium chloride (CaCl2) in a resorcinol aqueous solution to fabricate a casting solution. The activated membrane was cast and immersed into a sodium carbonate (Na2CO3) aqueous solution for taking the one-step NIPS-mineralization process. This proposed NIPS-mineralization mechanism comes to two conclusions: (i) the resulting membrane with comprehensive oleophobic properties and enhanced permeation flux for applications of oil/water separation with ultralow fouling and (ii) simplified the procedure to optimize the membrane performance using regular NIPS steps. The current work explores a one-step NIPS-mineralization technique that offers a novel approach to preparing membranes with highly efficient oil/water separation performance.

High performance gel polymer electrolyte based on P(MMA-co-Sty) and PVDF blend for fast-charging lithium metal batteries with extended cycle life

In the quest for high-energy-density lithium metal batteries (LMBs), the stabilization of lithium (Li) metal anodes during fast charging remains a formidable challenge. In this study, a novel copolymer, Poly(methyl methacrylate-co-styrene) (namely PMS) is synthesized and blended with Poly(vinylidene fluoride) to fabricate a porous gel polymer electrolyte (GPE, namely PMS-PVDF) through the nonsolvent-induced phase separation technique, which significantly enhances the electrochemical stability and fast-charging capabilities of LMBs. The developed GPE exhibits a high ionic conductivity of 5.62 mS cm−1, thereby reducing the formation of detrimental Li dendrites and leading to over 400 h stripping/plating process at 0.5 mA cm−2. Extensive electrochemical tests show that the LMBs with the obtained PMS-PVDF GPE achieve exceptional cycle stability over 600 and 1000 cycles at the C-rates of 0.5 and 3 C, respectively, outperforming traditional electrolytes. Furthermore, the ultra-stability of the quasi-solid-state electrolyte is demonstrated in a 375 mAh pouch cell setup, suggesting an essential trait for the practical application of high-power devices. This work marks a pivotal contribution to the field of energy storage, delivering insights and a clear methodology that pave the way for the development of next-generation LMBs poised for commercial viability.

Inhibiting Leidenfrost phenomenon with granulated polymer film

Inhibiting Leidenfrost phenomenon has been conventionally mediated by texturing materials to facilitate the solid-liquid contact or by arranging vapor channels to promote vapor evacuation. However, it remains challenging to break the trade-off between the high Leidenfrost point and the high heat transfer efficiency because elevating Leidenfrost point is often accompanied by the increase of thermal resistance. We propose a method using Rayleigh-Bénard-Marangoni convection and non-solvent induced phase separation to create granulated matrices that prevent the Leidenfrost effect at temperatures up to 400 °C. These matrices offer strong capillary adhesion, ensuring water droplets remain pinned and provide effective cooling. Additionally, the unique bubble dynamics prevent film boiling and Leidenfrost levitation. The matrices are mechanically robust and thermally stable, making them suitable for cooling high-power electronic devices at high temperatures. These results highlight the potential of using polymer matrices for cooling devices at elevated temperatures, potentially advancing cooling technologies.

Exploring green solvents for the sustainable fabrication of bio-based polylactic acid membranes using nonsolvent-induced phase separation

Green and sustainable membrane technology has recently gained attention from the membrane community to minimize the negative environmental impacts associated with conventional membrane production in industries, which rely on petrochemical engineering plastics and toxic organic solvents. While the fabrication of biobased and biodegradable polymeric membranes using common organic solvents has been reported, eco-friendly membrane-fabrication techniques using greener solvents are required to improve sustainability and reduce the negative environmental impact of the membrane industry. For the first time, this study comprehensively investigates the potential use of green solvents for preparing polylactic acid (PLA) membranes via the phase separation technique. PLA solubility and phase separation experiments, employing various green solvents were conducted to examine the potential applicability of these solvents for membrane fabrication. Porous PLA membranes exhibit different surface and pore structures depending on the thermodynamic and kinetic parameters of the green solvents. Based on the phase separation study, both fine PLA ultrafiltration membranes with controllable molecular weight cut-off and mechanically robust PLA microfiltration membranes with bi-continuous pore structure were successfully prepared using methyl lactate. The prepared green membranes showed a competitive filtration performance implying that the fully bio-based PLA membranes could substitute the conventional engineering plastic-based membranes in versatile membrane filtration and separation processes, especially single-use or consumable membrane products in environmental and healthcare industries.

FABRICATION AND CHARACTERIZATION OF POLYETHERSULFONE (PES) MEMBRANES BY BLENDING POLYMERS FOR REMOVAL OF ORGANIC COMPOUNDS IN AIR

The PES membrane was modified using a polymer blending method to improve the performance and characteristics of the membrane. This research aims to see the effect of adding biosilica additives on the performance characteristics of PES membranes and determine the optimal composition of additives and solvents for making membranes. The membrane was made using the Non-solvent Induced Phase Separation (NIPS) method with a composition consisting of 18% PES, with the addition of varying concentrations of silica (1%, 2%, 3%, and 4%) and the membrane using the solvent N-Methyl- 2 Pyrrolidone (NMP) and Dimethyl Sulfoxide (DMSO). Membrane characterization was carried out by observing membrane morphology using Scanning Electron Microscopy (SEM), membrane surface functional group analysis test using Fourier Tranform Infrared (FTIR), membrane porosity test using the dry-wet weight procedure method, the highest porosity value was found on membrane B2 using a solvent DMSO with 2% silica is 16.88%. Membrane performance was carried out by pure water flux testing, the highest pure water flux value was found in membrane B2 with 2% silica, namely 64.14 L/m2.h. The antifouling test uses flux ratio recovery, the highest antifouling value is found on the A3 membrane with 3% silica, namely 91.3%. As well as rejection of the humic acid solution as a Natural Organic Matter (NOM) sample model using the ultrafiltration (UF) module with a dead end filtration flow system, the highest rejection value was found on the B2 membrane with 2% silica, namely 64.4%.

2-Methylpyrazine: A Greener Solvent for Nonsolvent Induced Phase Separation (NIPS) Membrane Fabrication

2-Methylpyrazine: A Greener Solvent for Nonsolvent Induced Phase Separation (NIPS) Membrane Fabrication

A novel, green, and environmentally friendly PBS/nano-CaCO3 hybrid membrane

Biodegradable membrane materials can be degraded into small molecules under natural conditions, which can effectively alleviate the environmental pollution caused by the waste of traditional organic membrane materials. In this work, biodegradable poly (butylene succinate) (PBS)/nano-CaCO3 hybrid membranes has been prepared via non-solvent induced phase separation method by blending environmentally friendly nano-CaCO3 particles with PBS. The incorporation of nano-CaCO3 particles into the membrane leads to a notable enhancement in mechanical strength, from 1.03±0.05 MPa to 1.42±0.13 MPa, resulting in a substantial increase of approximately 37 %. Additionally, the introduction of these particles also contributes to a reduction in contact angle, from 63° to 56°. Consequently, the issue of inadequate mechanical strength and limited hydrophilicity of PBS membrane is effectively addressed. Moreover, the pure water permeance of membrane increases from 8.5 L·m−2·h−1·bar−1 to 89.3 L·m−2·h−1·bar−1, and the permeability is greatly improved. The permeance recovery rate of the membrane increases from 78 % to 95 %, and the anti-fouling performance is improved. In addition, PBS can be degraded after the service of PBS/nano-CaCO3 hybrid membrane, and CaCO3 particles are environmentally friendly. Therefore, the PBS/nano-CaCO3 hybrid membrane hybrid membrane prepared in this study is a green and environmentally friendly membrane material.

PH-responsive size- and charge-selective block copolymer membrane for the separation of small proteins

Blue-light-induced RAFT polymerization was utilized to synthesize poly(N,N-dimethylacrylamide)–block–polystyrene (PDMA–b–PS) diblock copolymers to obtain 40 g per batch for membrane fabrication. Larger isoporous membranes (≈ 0.5 m · 0.3 m) with pore diameters of ≈ 25 nm in the dry state and around 4 nm in the wet state were obtained by the combination of self-assembly and non-solvent induced phase separation (SNIPS). Membranes were post-modified with hydrochloric acid to impart negatively charged, pH-responsive poly(acrylic acid)–block–polystyrene (PAA–b–PS) membranes. Meanwhile all proteins like cytochrome C, insulin, lysozyme, myoglobin, and ovalbumin were fully rejected by the pristine PDMA–b–PS membrane, the PAA–b–PS membrane exhibited the rejection of proteins with a hydrodynamic radius Rh ≥ 1.9. A real selectivity of 4.1 for the positively charged protein cytochrome C compared to the similarly sized, but negatively charged insulin, as well as a real selectivity of 16.1 towards the negatively charged ovalbumin was obtained showing the size- and charge-selective characteristics of the PAA–b–PS membrane for protein separation.

Synergistic Interaction of Ionic Liquid Grafted Poly(vinylidene Fluoride) and Carbon Nanotubes to Construct Water Treatment Membranes with Multiple Separation Properties.

In this study, the dual strategy of 1-butyl-3-vinylimidazolium bromide ionic liquid (IL) grafting and carbon nanotubes (CNTs) nanocomposition was applied to modify poly(vinylidene fluoride) (PVDF)-based membranes. The highly hydrophilic/oleophobic and fouling-resistant PVDF-g-IL/CNTs membranes with excellent separation efficiency were obtained by the nonsolvent-induced phase separation method with ethanol-water mixed solution as the coagulation bath. The grafted IL not only generated hydrophilic groups on PVDF chains but also acted together with the CNTs to induce the formation of hydrophilic β-crystalline phase of PVDF, which significantly improved the hydrophilicity and pore structure of the modified PVDF membranes. As a result, the pure water flux of the optimal membrane increased up to 294.2 L m-2 h-1, which was 5.2 times greater than that of the pure PVDF membrane. Simultaneously, the electrostatic interaction of the positive IL and the integration of CNTs enhanced adsorption sites of the membranes, producing exceptional retention and adsorption of dye wastewater and oil-water emulsion. This study presents a straightforward and efficient approach for fabricating PVDF separation membranes, which have potential applications in the purification of various polluted wastewater.

Controlling the polymorphs of PVDF membranes: Effects of a salt additive on PVDF polarization during phase separation processes

Polyvinylidene fluoride (PVDF) membranes, acclaimed for their outstanding chemical resistance, thermal stability, and mechanical properties, play a crucial role in diverse industrial purification applications. While various methods have been employed for fabricating PVDF membranes such as thermally induced, evaporation-induced, vapor-induced, and nonsolvent-induced phase separation processes, controlling the polarity of PVDF chains using these techniques remains challenging. Recent studies have shown that the nonpolar α-phase PVDF is susceptible to organic acid fouling owing to hydrophobic interactions, whereas the β-phase PVDF has demonstrated polarity and offers antifouling properties. Herein, porous PVDF membranes predominantly composed of the β-phase were successfully fabricated by incorporating a small amount of LiCl salt into the PVDF dope solution. The addition of LiCl influences ion–dipole moments between ions and PVDF during phase separation, simultaneously affecting the PVDF chain arrangement and membrane morphology. Since the LiCl additive alters both the pore size and structure of PVDF membranes, both freestanding and non-woven supported membranes were prepared and characterized to assess the effects of polarity and pore size on fouling tendency. Characterizations of prepared PVDF membranes revealed considerable changes in the PVDF polymorph, membrane morphology, pore size, and antifouling properties upon introducing the salt additive. Our findings imply that β-phase–dominant PVDF membranes can be effectively utilized in water purification applications.

Highly Stretchable Polyurethane Porous Membranes with Adjustable Morphology for Advanced Lithium Metal Batteries.

A highly flexible, tunable morphology membrane with excellent thermal stability and ionic conductivity can endow lithium metal batteries with high power density and reduced dendrite growth. Herein, a porous Polyurethane (PU) membrane with an adjustable morphology was prepared by a simple nonsolvent-induced phase separation technique. The precise control of the final morphology of PU membranes can be achieved through appropriate selection of a nonsolvent, resulting a range of pore structures that vary from finger-like voids to sponge-like pores. The implementation of combinatorial DFT and experimental analysis has revealed that spongy PU porous membranes, especially PU-EtOH, show superior electrolyte wettability (472%), high porosity (75%), good mechanical flexibility, robust thermal dimensional stability (above 170 °C), and elevated ionic conductivity (1.38 mS cm-1) in comparison to the polypropylene (PP) separator. The use of PU-EtOH in Li//Li symmetric cell results in a prolonged lifespan of 800 h, surpasing the longevity of PU or PP cells. Moreover, when subjected to a high rate of 5 C, the LiFePO4/Li half-cell with a PU-EtOH porous membrane displayed better cycling performance (115.4 mAh g-1) compared to the PP separator (104.4 mAh g-1). Finally, the prepared PU porous membrane exhibits significant potential for improving the efficiency and safety of LMBs.

Investigating the impact of the sulfonation degree in sulfonated polyphenylsulfone (sPPSU) on PES/sPPSU polymer blend membranes

Polyethersulfone (PES) has widespread applications due to its excellent processability, mechanical strength, and chemical resistance. Nevertheless, its hydrophobic nature often leads to severe fouling and permeance decline. To improve the hydrophilicity of PES membranes, polymer blending is one of the most common methods. In this work, a series of sulfonated polyphenylene sulfones (sPPSU) with 1.9, 4.5, 8.2, 12.7, 19 degrees of sulfonation (DS) were synthesized and used to blend with PES. The PES/sPPSU blends were found to be compatible by calculating their theoretical enthalpy of mixing and measuring their glass transition temperatures (Tg's) at a blend weight ratio of 1:1. Ultrafiltration (UF) membranes were cast using the nonsolvent-induced phase separation (NIPS) method. It was found that 50/50 PES/sPPSU blend membranes with a DS equaling to or exceeding 8.2 eliminated finger-like macrovoids, resulting in a thinner and tight cross-sectional structure. A higher DS of sPPSU rendered the blend membranes with more hydrophilicity and oleophobicity as well as a more negatively charged surface. The unmodified PES membrane had rejections of 87.47 % and 91.5 % in ultrafiltration tests using feed solutions containing BSA and oil/water emulsion, respectively. The rejections could be further increased to 99.37 % and 97.17 % respectively by the blend membranes. The blend membranes consisting of a higher DS of sPPSU also exhibited a higher permeance, lower BSA absorption and better anti-fouling properties than the PES membrane.

Preparation and performance study of waste plastic blended ultrafiltration membrane

Waste plastic packaging bags (rPVC) and waste milk tea straws (rPLA) were used as membrane materials to prepare ultrafiltration (UF) membranes by the non-solvent induced phase separation (NIPS) method. The study aimed to investigate the influence of various factors, including different rPVC contents (10 wt%-20 wt%), membrane fractions (rPVC/rPLA), additive fractions (Pluronic F-127/PVP-K30), and different additive contents (0.5 wt%-3.0 wt%), on the performance of the membranes. The permeability, morphology, hydrophilicity, chemical composition, thermal stability, and antifouling properties of the blended UF membranes were thoroughly investigated. The experimental results revealed that the presence of rPLA and Pluronic F-127 increased the porosity, water absorption, pore size, and hydrophilicity of the blended UF membranes. Furthermore, the introduction of rPLA enhanced the thermal stability of the blended UF membranes. Additionally, the incorporation of Pluronic F-127 further improved the overall performance of the blended UF membranes. Specifically, it was found that the blended UF membranes achieved a pure water flux (PWF) of 192.50 L·m−2·h−1, while maintaining a bovine serum albumin (BSA) rejection rate of 95.20%. These results were obtained using a content ratio of rPVC/rPLA (90/10) at 14 wt% and an additive content of Pluronic F-127 at 2.5 wt%. By comparing with the blended UF membranes without introducing additives into the casting solution, the roughness (Ra) was reduced by 40.3%, the water contact angle (WCA) was reduced by 7.5%, the flux recovery rate (FRR) was increased by 80.5%, and the fouling resistance was enhanced.

Influence of PEG-PPG-PEG Block Copolymer Concentration and Coagulation Bath Temperature on the Structure Formation of Polyphenylsulfone Membranes.

The effect of amphiphilic block copolymer polyethylene glycol (PEG)-polypropylene glycol (PPG)-PEG concentration in the polyphenylsulfone (PPSU) casting solution and coagulation bath temperature (CBT) on the structure, separation, and antifouling performance of PPSU ultrafiltration membranes was studied for the first time. According to the phase diagram obtained, PPSU/PEG-PPG-PEG/N-methyl-2-pyrrolidone (NMP) systems are characterized by a narrow miscibility gap. It was found that 20 wt.% PPSU solutions in NMP with the addition of 5-15 wt.% of PEG-PPG-PEG block copolymer feature upper critical solution temperature, gel point, and lower critical solution temperature. Membrane composition and structure were studied by Fourier-transform infrared spectroscopy, scanning electron and atomic force microscopies, and water contact angle measurements. The addition of PEG-PPG-PPG to the PPSU casting solution was found to increase the hydrophilicity of the membrane surface (water contact angle decreased from 78° for the reference PPSU membrane down to 50° for 20 wt.%PPSU/15 wt.% PEG-PPG-PEG membrane). It was revealed that the pure water flux increased with the rise of CBT from 18-20 L·m-2·h-1 for the reference PPSU membrane up to 38-140 L·m-2·h-1 for 20 wt.% PPSU/10-15 wt.% PEG-PPG-PEG membranes. However, the opposite trend was observed for 20 wt.% PPSU/5-7 wt.% PEG-PPG-PEG membranes: pure water flux decreased with an increase in CBT. This is due to the differences in the mechanism of phase separation (non-solvent-induced phase separation (NIPS) or a combination of NIPS and temperature-induced phase separation (TIPS)). It was shown that 20 wt.% PPSU/10 wt.% PEG-PPG-PEG membranes were characterized by significantly higher antifouling performance (FRR-81-89%, DRr-26-32%, DRir-10-20%, DT-33-45%) during the ultrafiltration of bovine serum albumin solutions compared to the reference PPSU membrane prepared at different CBTs (FRR-29-38%, DRr-6-14%, DRir-74-89%, DT-88-94%).

A Radiative-Cooling Hierarchical Aligned Porous Poly(vinylidene fluoride) Film by Freeze-Thaw-Promoted Nonsolvent-Induced Phase Separation

A Radiative-Cooling Hierarchical Aligned Porous Poly(vinylidene fluoride) Film by Freeze-Thaw-Promoted Nonsolvent-Induced Phase Separation

Highly stable, antibacterial and antiviral composites films via improved non-solvent induced phase separation for textile application

Textile composites are ubiquitous in daily life and are one of the main ways in which bacteria and viruses spread. Highly effective antibacterial and antiviral flexible composites are effective for reducing microbe transmission. Herein, we reported an improved nonsolvent-induced phase separation method for the fabrication of flexible textile composites. Cu2O/polyurethane (Cu2OPU) composite films containing antibacterial and antiviral coatings were constructed using a Cu2O-polyvinyl butyral coagulation bath and binary solvent mixtures, yielding a composite that had excellent mechanical properties and stability and the components did not leach out. The as-prepared Cu2OPU composite films exhibited strong antibacterial and antiviral activity against Staphylococcus aureus and the H1N1 virus (above 99.99 % inactivation ratio). What’s more, Cu2OPU has excellent mechanical and environmental stability owing to the strong interfacial adhesion of Cu2O with the polymer matrix. Furthermore, it can withstand multiple washes and be suitable for daily use. Cu2OPU may be sustainably produced with great scalability, which may meet public, home, and textile applications.

Polypropylene membranes prepared via non-solvent/thermally induced phase separation: Effect of non-solvent nature

The goal of this work was to investigate the effect of non-solvent nature on the formation of porous membranes via non-solvent/thermally induced phase separation (N-TIPS). The hot solution of polypropylene (PP) in a mixture of dioctyl phthalate (DOP) and dibutyl phthalate (DBP) at 210 °C was placed as a thin film on a polyethylene terephthalate (PET) substrate, and then precipitated by immersion in the non-solvent (water, iso-propanol, 1-hexanol, or 1-decanol) at room temperature. It was found that the non-solvent nature greatly affected the morphology of the thin skin layer of the membrane facing the precipitation bath, which can be attributed to non-solvent induced phase separation (NIPS). The affinity between the polymeric solution and corresponding non-solvent was evaluated by using Hansen solubility parameters of components taken at room temperature and extrapolated to the temperature of 210 °C. An increase in the affinity between the non-solvent and the polymer transformed the surface layer structure from almost monolithic to cellular (with different pore sizes and porosity) and to spherulitic types. The non-solvent nature played a less pronounced role in the formation of the porous structure of the membrane bulk and the back side of the membrane (facing the PET substrate). Since the morphology of the rest of the membrane was correlated with thermophysical properties of non-solvents, it was concluded that the membrane formation took place due to temperature induced phase separation (TIPS). In the case of water, which has the highest cooling rate, the polypropylene crystallized by forming a “smectic” structure, while the standard α-lamellar structure was observed for other non-solvents. To gain insight into the TIPS process, a model of unsteady one-dimensional heat transfer was applied to simulate the change in the temperature profile of the hot, thin film of polymeric solution placed in the corresponding non-solvent. The resulting membranes were mainly in the microfiltration range with a mean through pore size of 0.05–0.61 μm, and iso-propanol permeance of 2.1–8.4 m3 m−2∙h−1∙bar−1. The rejection of 500 nm polystyrene microspheres was in the range of 45–98 %. The tensile strength was in the range of 2.9–3.2 MPa, and elongation at break was 30–190 % with respect to the non-solvent used.