Vapor-induced Phase Separation Research Articles

Facile Synthesis of Palladium Nanorods: Self-Assembly into Thin 2D Layers for SERS Sensing

This study presents a simple, high-throughput synthesis approach for fabricating palladium (Pd) nanomaterials with anisotropic shapes, specifically Pd nanorods, via a self-assembly process. This method avoids the use of reducing agents, surface functionalization, and stabilizing agents. Palladium–poly(methyl methacrylate) (Pd-PMMA) nanocomposites were successfully synthesized using a vapor-induced phase separation (VIPS) method. The formation of Pd nanorods was controlled by tuning key parameters, such as the Pd precursor concentration, choice of solvents, and spin coating speed. Notably, the resulting nanorods exhibited high reproducibility and ultrasensitivity as a surface-enhanced Raman scattering (SERS) platform, achieving an enhancement factor of approximately 1.8 × 105, despite the relatively weak plasmonic properties of Pd. This work represents a novel, facile strategy for Pd nanorod synthesis, offering new potential for the design of Pd-based nanosensors for chemical sensing applications.

Preparation of polyvinylidene fluoride membranes with enhanced hydrophobicity and its applications in chromium recovery using supported liquid membranes in practical scale

This study focuses on the development of polyvinylidene fluoride (PDVF) membranes with enhanced hydrophobicity and their application for supported liquid membrane (SLM)-based solvent extraction. Flat sheet membranes were prepared via vapor-induced phase separation (VIPS), followed by non-solvent-induced phase separation (NIPS). PVDF flat sheet membrane was prepared with different solvents, namely N-methylpyrrolidone, dimethylformamide (DMF), dimethylacetamide, and dimethylsulfoxide, and at different VIPS times. The effect of different solvents and VIPS time on the membrane characteristics and performance was studied. PVDF membrane prepared with DMF solvent with VIPS time of 7.5 min gave optimum results in terms of membrane characteristics and performance with a water contact angle of 95.5°. The optimized PVDF flat sheet membrane was used as support in a SLM setup for the extraction and recovery of chromium from a simulated aqueous feed solution similar to tannery effluent with concentrations ranging from 5 to 75 ppm. Dodecane, modified with 1-dodecanol and decalin, was used as an organic solvent with tri-caprylmethylammonium chloride (Aliquat 336) as an extractant. NaNO3 solution was used as a stripping solution. The processes of extraction and stripping were carried out simultaneously in a single-step operation to recover chromium. The extraction of chromium achieved in 3 h using an in-house-prepared hydrophobic PVDF membrane as support for the liquid membrane varies from 63.08% for feed containing 5 ppm chromium to 50.59% for feed containing 75 ppm chromium, with a maximum extraction of 70.92% for feed with 50 ppm chromium.

Injectable ultrathin porous membranes harnessing shape memory polymers for retinal tissue engineering.

Age-related macular degeneration (AMD) is a leading cause of vision loss, characterized by the progressive degeneration of retinal cells, particularly retinal pigment epithelial (RPE) cells. Conventional treatments primarily focus on slowing disease progression without providing a cure. Recent advances in tissue engineering and cell-based therapies offer promising avenues for regenerating retinal tissue and restoring vision. In this study, we developed ultrathin, nanoporous membrane scaffolds designed to mimic Bruch's membrane (BrM) for RPE cell transplantation using vapor-induced phase separation. These scaffolds, fabricated from a blend of poly(L-lactide-co-ε-caprolactone) (PLCL) and poly(lactic-co-glycolic acid) (PLGA), exhibited favorable topography, biocompatibility, and shape-memory properties. In vitro experiments confirmed that the nanoporous topography effectively supports the formation of RPE monolayers with intact tight junctions. Additionally, the shape-memory characteristic enables the membrane to self-expand at body temperature (37 °C), facilitating minimally invasive delivery via injection. ARPE-19 cell-attached nanothin membranes successfully demonstrated shape-recovery properties and were deliverable through a catheter in an ex vivo model. Our findings suggest that the developed scaffolds provide a promising approach for retinal tissue engineering and could significantly contribute to advanced treatments for AMD and other retinal degenerative diseases.

Vapor induced phase separation approach for fabricating high-performance PVDF-HFP/PEO polymer electrolyte membranes with improved electrochemical properties

Vapor induced phase separation approach for fabricating high-performance PVDF-HFP/PEO polymer electrolyte membranes with improved electrochemical properties

Fabrication and Characterization of PPSU/PES Blend Nanofiltration Membrane via VIPS‐NIPS Method for Effective Dye Rejection

ABSTRACTIndustrial effluents, including dyes, pose a threat to the environment and human health, as they are resistant to reacting with oxygen; therefore, they are rarely biodegradable. Among the various processes, nanofiltration is an attractive process for separating dyes from water due to its economic efficiency. This work represents the fabrication of poly (phenyl sulfone) (PPSU)/poly (ether sulfone) (PES) blend nanofiltration membranes through vapor‐induced phase separation (VIPS) followed by immersion precipitation. The influence of polymer blend, exposure time, and coagulation bath composition on membrane characteristics and performance was studied. Results illustrate that an increment in exposure time caused a thinner top layer and changed the cross‐section morphology from finger‐like to sponge‐like. At PPSU:PES = 50:50 blend ratio, the pore radius significantly got larger than the neat polymers' fabricated membranes. The addition of N‐methyl‐2‐pyrrolidone (NMP) in the coagulation bath causes the formation of smaller finger‐like voids at the top layers and a sponge‐like structure in the sub‐layers of membranes. The optimal conditions for the nanofiltration membrane were determined at 28 s VIPS time, an equal ratio of polymers, and pure water as the coagulation bath. Under these conditions, the distilled water permeability and Rose Bengal rejection were determined as 63.6 L/m2 h and 77.11%, respectively.

Prevention of Protein Adsorption and Macrophage Phagocytosis of Perfluorocarbon-Based Microsized Core-Shell Artificial Oxygen Carriers by Facile PEG Coatings.

Polyethylene glycol (PEG)-coated microsized artificial oxygen carriers (AOCs) with a perfluorooctyl bromide (PFOB) core and poly(lactide-co-caprolactone) (PLC) shell were successfully fabricated using Shirasu porous glass (SPG) membrane emulsification. The PEG coating was achieved by adding the polylactide-b-polyethylene glycol-b-polylactide (PLA-PEG-PLA) block copolymer to the disperse phase during the SPG membrane emulsification process. During the DCM evaporation process, the three-layer structure of the PEG layer, PLC shell, and PFOB core of the AOCs spontaneously formed by phase separation. By adjustment of the ratio of PLA to PLA-PEG-PLA, the PEG chain density on the AOC surface was controlled and estimated as 0.1-2.4 chains nm-2 based on quantitative proton nuclear magnetic resonance analysis. It was expected that a loop PEG brush structure was formed on the surface of the AOCs owing to the ABA block copolymer structure of PLA-PEG-PLA. With the increase in PEG chain density, nonspecific adsorption of bovine serum albumin, γ-globulin, and fibrinogen to AOCs decreased drastically and reached below 10 μg cm-2. Additionally, phagocytosis of the AOCs, evaluated using the macrophage cell line RAW 264.7, was effectively prevented and the phagocytosis index decreased from 2 to almost 0. Finally, the PEG-coated core-shell AOCs exhibited excellent higher cell viability to RAW 264.7 than bare AOCs and showed oxygen delivery to hypoxia-responsive HeLa cells. Effective facile PEG coating on PFOB/PLC core-shell AOCs was successfully achieved simultaneously with membrane emulsification and subsequent evaporation-induced phase separation. It will be an effective strategy for membrane emulsification technology as well as the preparation of AOCs.

High Performance Antibacterial Structure‐Tuned Hemofiltration Membrane for Facile Permeability of Blood Plasma During Plasmapheresis

ABSTRACTA microfiltration membrane is designed to separate blood cells without altering plasma composition. A vapor‐induced phase separation (VIPS) combined with compositional adjustment is used to create a structure‐tuned hemofiltration membrane. Polyvinylpyrrolidone (PVP‐K90), polyethylene glycol (PEG400), and either water or chlorohexidine gluconate (CHG) solution are employed to regulate membrane structure and provide antibacterial enhancement. The preparation conditions involve a 5‐min VIPS process at moderate temperature and high humidity to craft the desired membrane structure. Morphological studies show that the membranes have an asymmetric sponge‐like structure with controlled surface pore sizes that effectively separate blood cells while enabling plasma passage. Complete blood count (CBC) analysis reveals that MH2 and MH3 membranes exhibit significant potential for blood cell separation, with 78% platelet (PLT) separation, 80% red blood cell (RBC) separation, and over 90% white blood cell (WBC) separation. Biochemical analysis of plasma substances confirms that components such as fasting blood sugar (FBS), blood urea nitrogen (BUN), creatinine, albumin, high‐density lipoprotein, and low‐density lipoproteins pass through the MH series without significant concentration changes. The outcomes suggest that the MH series offers high blood compatibility as evidenced by coagulation times and hemolysis ratio. In addition, MTT data validates the biocompatibility of the membrane. Biofilm inhibition results and biofouling study confirmed that MH series, especially MH2 and MH3 exhibit superior characteristics and performance for plasmapheresis applications.

Designing Phenolphthalein-Based Adsorptive Membranes for the High-Affinity, High-Capacity Capture of Contaminants from Water.

The selective removal of solutes is crucial for ensuring a sustainable water supply, recovering resources, and cost-effective biomanufacturing. Adsorptive membranes are promising in this regard due to their rapid mass transfer and low energy demands. However, state-of-the-art adsorptive membranes offer limited pore sizes and surface chemistries. This study reports the development of adsorptive membranes from reactive phenolphthalein-based (PPH-based) polymers. These polymers, which are molecularly engineered to possess a high density of reactive pendant groups, are transformed into porous membranes through a surface-segregation vapor-induced phase separation (SVIPS) method. Examining the thermodynamic characteristics of the polymer-solvent-nonsolvent system informs the SVIPS manufacturing process and facilitates the formation of diverse membrane morphologies with hydraulic permeabilities ranging from 3400 to 13,500 L m-2 h-1 bar-1. Copper ion binding experiments demonstrate a saturation capacity of 0.9 mmol Cu2+ g-1, indicating high accessibility of the pendant groups for postsynthetic modification. Functionalization with alkyne groups enables one-step click reactions, such as the thiol-yne and Cu(I)-catalyzed azide-alkyne cycloaddition, expanding the membrane functionality. The incorporation of cucurbit[7]uril-azide macrocycles demonstrates the affinity-mediated capture of methyl viologen from solution. The combination of PPH-based polymers and the SVIPS method provides a versatile adsorptive membrane platform with a dense presentation of reactive sites, facilitating customization through diverse and high-yielding reactions.

Engineering bio-inert and thermostable poly(vinylidene difluoride) membranes by grafting thermal-tolerant copolymers via ring-opening reaction

Engineering bio-inert and thermostable poly(vinylidene difluoride) membranes by grafting thermal-tolerant copolymers via ring-opening reaction

Anti-swelling gel polymer electrolyte membrane for high-performance lithium-ion battery

Anti-swelling gel polymer electrolyte membrane for high-performance lithium-ion battery

High-performance radiative cooling PVDF-HFP film based on controllable porous structure

High-performance radiative cooling PVDF-HFP film based on controllable porous structure

Membranes of Amphiphilic Polyamide 1012 Prepared via Mixed ‘Non-solvents’ Evaporation Induced Phase Separation

Membranes of Amphiphilic Polyamide 1012 Prepared via Mixed ‘Non-solvents’ Evaporation Induced Phase Separation

Highly sensitive and stretchable CB/GNPs-TPU strain sensor with porous microstructure for multifunctional strain sensing

Highly sensitive and stretchable CB/GNPs-TPU strain sensor with porous microstructure for multifunctional strain sensing

Fabrication of CNC-AC bionanosorbents from the residual mass of Magnolia champaca l. Bark after methanol extraction for wastewater treatment: Continuous column adsorption study

Fabrication of CNC-AC bionanosorbents from the residual mass of Magnolia champaca l. Bark after methanol extraction for wastewater treatment: Continuous column adsorption study

Optimizing PES microfiltration membranes for sterile filtration: A comparative study of polydopamine coating in acidic and basic conditions to minimize protein adsorption

Optimizing PES microfiltration membranes for sterile filtration: A comparative study of polydopamine coating in acidic and basic conditions to minimize protein adsorption

Multilayer porous poly (vinylidene fluoride)/MXene/cobalt ferrite composites with ternary gradients for electromagnetic wave absorption

A composite material with a high potential for absorbing electromagnetic waves (EMW) was obtained by selecting poly (vinylidene fluoride) (PVDF) as the matrix, MXene as the conductive filler, and cobalt ferrite (CoFe2O4) as the magnetic filler. A layer-by-layer assembly strategy involved hot pressing and sequential blade coating, followed by vapor-induced phase separation, was used to implement the preparation of PVDF/MXene/CoFe2O4 (PMC) composites. The process facilitates the formation of a well-organized multilayer porous framework, providing a gradient of positive conductivity, negative magnetism, and porosity within the composites. Incorporating distinct multilayer, porous, and gradient structures into a single composite led to exceptional impedance matching (Z), with an area percentage of up to 8.4% in the optimal range of 0.8 to 1.2. Furthermore, the multiple interfaces formed by the various components, multilayer structure, and porous configuration significantly enhanced the EMW attenuation capability, with the attenuation constant reaching as high as 274. Consequently, the PMC composite demonstrated outstanding performance with a minimal reflection loss (RLmin) of -56.5dB, a specific RLmin of 23.5dB/mm, and the broadest effective absorption bandwidth of 3.2GHz. The combination of the competitive EMW absorption capability, low density, flexibility, adequate tensile strength, and amphiphilic Janus surface may significantly broaden the application scenarios of PMC composites.

Self‐cleaning films of biopolymer polyhydroxybutyrate with different semiconductors incorporation: Development, characterization, and photocatalytic activity evaluation

AbstractSelf‐cleaning hydrophobic films were developed using polyhydroxybutyrate (PHB), enhanced with titanium dioxide (TiO2), bismuth oxyiodide (BiOI), and a BiOI/α‐Fe2O3 heterojunction. This is the first study to analyze the photoactivity of BiOI and BiOI/α‐Fe2O3 immobilized into PHB. Alternative solvents for dissolving PHB were investigated. Additionally, formation methods such as casting in Petri dishes, as well as controlled thickness casting through non‐solvent‐induced phase separation (NIPS), and evaporation‐induced phase separation (EIPS), were employed and compared. Despite differing morphologies, both NIPS and EIPS films exhibited similar photocatalytic activity, suggesting that only the catalyst on the external surface of the film is active. The highest pseudo first‐order apparent kinetic constant (0.1468 ± 0.0015 min−1 g−1) was found in films with the lowest polymer and catalyst concentrations analyzed (5% and 3% ). A double‐layer film preparation method was proposed to enhance photocatalytic activity, resulting in a 70% increase in the kinetic constant (0.2506 ± 0.0019 min−1 g−1). Double‐layer composite films with BiOI and BiOI/α‐Fe2O3 showed photocatalytic activity comparable to TiO2 under UV–visible light. Furthermore, their photocatalytic activity under visible light was confirmed, unlike TiO2, which exhibits a negligible kinetic constant in this wavelength range.

Electrospun Fiber Surface Roughness Modulates Human Monocyte-Derived Macrophage Phenotype.

Injuries to fibrous connective tissues have very little capacity for self-renewal and exhibit poor healing after injury. Phenotypic shifts in macrophages play a vital role in mediating the healing response, creating an opportunity to design immunomodulatory biomaterials which control macrophage polarization and promote regeneration. In this study, electrospun poly(-caprolactone) fibers with increasing surface roughness (SR) were produced by increasing relative humidity and inducing vapor-induced phase separation during the electrospinning process. The impact of surface roughness on macrophage phenotype was assessed using human monocyte-derived macrophages in vitro and in vivo using B6.Cg-Tg(Csf1r-EGFP)1Hume/J (MacGreen) mice. In vitro experiments showed that macrophages cultured on mesh with increasing SR exhibited decreased release of both pro- and anti-inflammatory cytokines potentially driven by increased protein adsorption and biophysical impacts on the cells. Further, increasing SR led to an increase in the expression of the pro-regenerative cell surface marker CD206 relative to the pro-inflammatory marker CD80. Mesh with increasing SR were implanted subcutaneously in MacGreen mice, again showing an increase in the ratio of cells expressing CD206 to those expressing CD80 visualized by immunofluorescence. SR on implanted biomaterials is sufficient to drive macrophage polarization, demonstrating a simple feature to include in biomaterial design to control innate immunity.

A green bulk modification for imparting a green VIPS membrane with antifouling properties

A green bulk modification for imparting a green VIPS membrane with antifouling properties

Electrothermal composite membranes of PVDF-g-IL embedded in steel mesh: Fabrication via VIPS and separation of water-in-perfluoropolyether emulsion with high-viscosity

Electrothermal composite membranes of PVDF-g-IL embedded in steel mesh: Fabrication via VIPS and separation of water-in-perfluoropolyether emulsion with high-viscosity