Phase Inversion Research Articles

Mechanical enhancement and high linearity health monitoring of composite materials based on CNTs/PSF/PI film sensor with ultra-low SWCNTs doping content.

A new type of embedded composite material health monitoring nano-sensor is designed to ensure that the unique material advantages of nanofillers can be maximized. The carbon nanotubes (CNTs)/polysulfone (PSF)/polyimide (PI) thin film sensor in this paper is obtained by the self-assembly of a PSF/PI asymmetric porous membrane which is prepared by a phase inversion method through vacuum filtration of SWCNTs. It is a new structure for a practical CNT sensor that can take into account both 'composite health monitoring and damage warning' and 'composite mechanical enhancement'. The new structure of the CNTs/PSF/PI film sensor is divided into two parts. The upper part consists of small-aperture finger-like holes filled with SWCNTs (the SWCNT content is 0.0127 mg cm-2). The lower part consists of large-aperture cavities conducive to resin infiltration, which enhance the interface bonding force between the sensor and the composite material. This unique structure allows the CNTs/PSF/PI film sensor to change the influence of the embedded sensor from 'introducing defects' to 'local enhancement', and the mechanical strength of the enhanced specimen can reach up to 1.68 times that of the original specimen, and the service interval can reach 2.01 times that of the original specimen. In addition, the CNTs/PSF/PI film sensor also has good sensitivity (GF = 2.54) and extremely high linearity (R2 = 0.9995), and has excellent follow-up and interface bonding ability. It can also maintain excellent fatigue resistance and stability over 46 500 vibration cycles, which provides new research ideas and research methods for the field of composite-life monitoring sensors.

Cellulose acetate/metal-organic framework composite beads with macroporous adsorption channels as a novel hemoadsorbent for effective virus capture.

Due to their rapid spread, high variability, and drug-resistant strains, new viral infections are continuously emerging. A lack of effective antiviral drugs and vaccines, resulting in disease and death, has significant socioeconomic consequences. Hemoperfusion can effectively adsorb and remove toxins from the blood, thus purifying the blood and serving as an acute treatment. Therefore, the aim of this study was to construct adsorbents to selectively remove viruses from the blood to quickly treat pathogen infection. We reported on new metal-organic framework (MOF)-polymer beads based on MIL-53(Al) and cellulose acetate (CNC), which were prepared by a one-step phase inversion method and applied as a viral hemo-adsorbent for the first time. The characterization results demonstrated that MIL-53(Al) was well dispersed in the CNC matrix. The adsorption results demonstrated that the capture efficiency of the human immunodeficiency virus (HIV) could exceed 99.93%, and the corresponding infectious titer decreased by approximately 103 times in clinical application. Moreover, CNC/MIL-53 exhibited low hemolysis ratios and good anticoagulant properties. Furthermore, molecular dynamics simulations revealed that the interplay of hydrogen bonding was the governing physisorption mechanism. Overall, CNC/MIL-53 could serve as a new type of hemoperfusion adsorbent for virus removal from blood and provide a new treatment pathway to mitigate epidemics.

Physicochemical properties of functionalized A200 and SBA-15 nanoparticles with enhanced amphiphilicity for Pickering emulsions

Pickering emulsions stabilized by functionalized A200 and SBA-15 nanoparticles showed different stabilities, where the former was highly stable to be O/W and the latter was susceptible to a phase inversion from O/W to W/O type.

PH-regulated reversible phase inversion of poly(ionic liquid) aqueous two-phase systems

Smart aqueous two-phase systems (ATPSs) were fabricated using ferrocenyl and benzyl-modified poly(ionic liquid)s for the first time. The newly-developed ATPSs were found to be pH-sensitive. The upper phase and lower...

A strategy to build high-performance thick electrodes for lithium-ion batteries with enhanced compressive modulus and regulated tortuosity in the phase-inversion process

By tuning the composition of the non-solvent bath used in the non-solvent induced phase inversion process for fabricating thick and low-tortuosity battery electrodes, optimal electrochemical performances and compressive modulus were achieved.

Immobilization of carbonic anhydrase on modified PES membranes for artificial lungs.

The introduction of carbonic anhydrase (CA) onto an extracorporeal membrane oxygenation (ECMO) membrane can improve the permeability of carbon dioxide (CO2). However, existing CA-grafting methods have limitations, and the hemocompatibility of current substrate membranes of commercial ECMO is not satisfactory. In this study, a 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC)/N-hydroxy succinimide (NHS) activation method is adopted to graft CA with CO2-catalyzed conversion activity onto a polyethersulfone (PES) membrane, which is prepared by a phase inversion technique after in situ crosslinking polymerization of 1-vinyl-2-pyrrolidone (VP) and acrylic acid (AA) in PES solution. The characterization results reveal that CA has been grafted onto the modified PES membrane successfully and exhibits catalytic activity. The kinetic parameters of esterase activity verify that the grafted amount of active CA increases with an increase in the concentration of the CA incubation solution. The CA-grafted membrane (CA-M) can accelerate the conversion of bicarbonate to CO2 in water and blood, which demonstrates the special catalytic activity towards bicarbonate of CA. Finally, blood compatibility tests prove that the CA-M does not lead to hemolysis, shows suppressed protein adsorption and increased coagulation time, and is suitable for application in ECMO. This work demonstrates a green and efficient method for preparing bioactive materials and has practical guiding significance for subsequent pulmonary membrane research and ECMO applications.

Efficient removal of methyl orange and ciprofloxacin by reusable Eu-TiO2/PVDF membranes with adsorption and photocatalysis methods.

The presence of methyl orange (MO) and ciprofloxacin (CIP) in wastewater poses a serious threat to the environment and human health. Titanium dioxide nanoparticles (TiO2 NPs) are widely studied as photocatalysts for wastewater treatment. However, TiO2 NPs have the drawbacks of high energy required for activation, fast electron-hole pair recombination and difficulty in recovering from water. To overcome these problems, europium decorated titanium dioxide/poly(vinylidene fluoride) (Eu-TiO2/PVDF) membranes were successful prepared in this work by combining the modified sol-gel method and the immersion phase inversion method. The Eu-TiO2/PVDF membranes obtained with the increase of Eu-TiO2 NPs content during the preparation process were named M1, M2 and M3, respectively. The pure PVDF membrane without the addition of Eu-TiO2 NPs was named M0, which was prepared by the immersion phase inversion method and served as a reference. The prepared Eu-TiO2/PVDF membranes could not only adsorb MO, but also degrade CIP under visible-light irradiation. Moreover, the Eu-TiO2/PVDF membranes exhibited adsorption-photocatalytic activity towards a mixture of MO and CIP under visible-light irradiation. Last but not the least, the Eu-TiO2/PVDF membranes exhibited excellent recyclability and reusability, opening the avenue for a possible use of these membranes in sewage-treatment plants.

Preparation and characterization of high flux cellulose acetate/hydroxyapatite composite ultrafiltration membranes for water treatment

In this study, we prepared cellulose acetate/hydroxyapatite (CA/HA) composite ultrafiltration membranes for water treatment. The organic-inorganic composite ultrafiltration membranes were prepared by doping different contents of HA nanoparticles into the CA by phase inversion method. The structure and morphology of the HA nanoparticles and membranes were characterized by X-ray diffraction, Fourier infrared spectroscopy and Scanning electron microscopy. Thermogravimetric analysis was used to describe thermal characteristics. The contact angle value and wettability test were used to determine the hydrophilicity of the polymer membrane. In addition, fluxes and rejection rates were tested at different pollutant concentrations and different pH values. The pore size and porosity gradually increased and the hydrophilicity and thermal stability of membrane were improved with the deposited HA content. With the addition of 5 wt% HA, the tensile strength of the membrane reached a maximum value of 2.80 MPa. The fluxes of pure water, CR, MB and BSA were 152.23, 111.25, 125.69 and 87.47 L/(m2·h), while the rejection rates of CR, MB and BSA were 99.99 %, 92.91 % and 99.99 %, respectively. In addition, the rejection decreased with increasing dye concentration and showed higher rejection under alkaline conditions. On the whole, the produced CA/HA composite membranes exhibited significantly higher permeability and rejection rates, offering them a lot of potential for water treatment applications.

Fabrication and characterization of highly hydrophobic PVDF membrane by phase inversion method with high anti-wettability characteristics

Membrane gas-liquid separation technology has garnered significant attention in applications such as membrane desalination, distillation, and gas absorption due to its operational flexibility, compact design, and large specific interfacial area. However, the currently used membranes are prone to pore wetting under high operational pressures, transitioning from a non-wetted state to partially or fully wetted conditions. This undesired wetting increases mass transfer resistance for water vapor molecules, ultimately leading to reduced removal efficiency. To address this issue and enhance wetting resistance, membrane hydrophobicity needs to be improved. In this study, a highly hydrophobic polyvinylidene fluoride (PVDF) membrane was developed using the phase inversion method for membrane distillation applications. We mixed a 16wt% polymer concentration with N-Methylpyrrolidone (NMP) as a solvent at 50°C for 24 hours. Subsequently, the polymer solution was cast and exposed to different non-solvents, namely water and methanol, to investigate their impact. Surface morphology and hydrophobic properties of the synthesized membranes were analyzed using Scanning Electron Microscope (SEM) and a Goniometer. Our findings indicate that the PVDF membrane fabricated with methanol as the non-solvent exhibited a significantly higher water contact angle of 126°, compared to 70° when deionized water was used as the non-solvent. This change from water to methanol as the non-solvent resulted in a more symmetrical membrane structure, enhancing the water contact angle from 70° to 126°. It is interesting to note that increase in the water contact angle increases the hydrophobicity of the PVDF membrane.

Fabrication and characterization of polyether sulfone membrane with cellulose additive of oil palm empty fruit bunches for reducing iron content in water

Fabrication of polymer-based membranes polyether sulfone (PES) which is hydrophobic which is easily experiences fouling and will a decrease in membrane performance with the addition of various organic additives from oil palm empty fruit bunches (OPEFB) waste and dimethyl formamide (DMF) as solvents to look at the formation of Ultrafiltration membrane pores (UF). OPEFB additive concentration variations were 0%, 0.5%, 1%, and 1.5% for each addition of 18% PES polymer. The manufacture of cellulose was alkalization, bleaching, and acid hydrolysis. The characteristics were carried out by the FTIR test to see the wavelength of OPEFB cellulose where at 1093.64 cm -1 there is a C-O functional group which proves the presence of cellulose in OPEFB, SEM, and porosity tests on the membrane. Membranes with polyether sulfone polymer are prepared by a phase inversion process. The results obtained by the flux values with variations in additive concentration and pressure variations of 0.5 %, 1%, and 1.5% obtained flux and rejection results (selectivity) using FeCl3.

SVPWM based double loop control method of a three phase inverter for Microgrid Application

SVPWM based double loop control method of a three phase inverter for Microgrid Application

New boost type single phase inverters for photovoltaic applications with reduced device count.

In recent years, single-stage boost inverters with common ground have shaped the inverter markets due to the many benefits associated with these types of inverters, including their high efficiency, single control scheme, and integrated boost converter. A new boost-type inverter that utilizes a common ground and has fewer switches is proposed in this article. It uses two DC-link capacitors connected in parallel and discharged independently while being charged simultaneously. The voltage for the positive and negative half cycles is supplied by the capacitors located at the top and bottom of the circuit, respectively. In addition, a comparison is made between the proposed circuit and the boost inverter already in use in the literature. Using PLECS as the computing software, the efficiencies are determined depending on the various percentages of output power. To validate performance, present experimental data, and attain the best possible efficiency of 97%, a 400 W prototype model is constructed. In addition to that, the breakdown of the costs is shown.

Novel Substrate-Integrated Coaxial Line Phase Inverter and Magic-T

Novel Substrate-Integrated Coaxial Line Phase Inverter and Magic-T

Biobased Alkyd Acrylic Hybrid Core Shell Approach

The main objective of this work was to synthesize bio based alkyd-arcylic hybrid emulsion by using core shell approach. Step by step growing polymerization was used for the preparation of the bio-based alkyd resin. Bio-based sebacic acid was used in the synthesis. In the core shell approach; shell part contains acrylic polymer, core part contains bio based alkyd emulsion, which was synthesized by phase inversion. The acrylic shell was synthesized in the presence of the alkyd resin by the emulsion polymerization method.

Phase Inversion Gelation Process and Additive Effects on Hydrogel Film Properties of Cotton Cellulose.

During the preparation of cotton cellulose hydrogels using the phase inversion gelation method of N,N-dimethylacetamide/LiCl solution under ethanol vapor, acetone (AC), methyl ethyl ketone (MEK), or diethyl ketone (DEK) were added as additives, and their gelation state and the properties of the resulting hydrogels were evaluated. Adding the ketones to the cellulose solution caused an increase in the gelation time, but the solution viscosity decreased, indicating that the cellulose tended to aggregate in the solution. Among the hydrogels prepared by adding ketones, the water content was as high as 2050%, especially for AC and MEK. In these hydrogels, cellulose formed an agglomerated fibrous network of a few micron widths, forming a tuft-like entrapment space of about 10 to 100 μm size. The structure surrounded water and held it in the hydrogels. The FTIR results showed that the water, which formed hydrogen bonds, was retained within the hydrogel network. This structural configuration was determined to be conducive to maintaining the gel state against external deformation forces, especially in the case of the addition of MEK.

Carbon nanotube-based photothermal membrane for efficient cold air heating and removal of particulate matter and airborne bacteria

Indoor heating results in high energy consumption and severe atmospheric pollution. Although the development of solar air heaters provides a sustainable route for indoor thermal comfort, such heaters still face challenges in terms of adequate heat exchange and filtering of atmospheric pollutants. Inspired by solar-driven interfacial evaporation, we propose a multifunctional carbon nanotube-based photothermal membrane for efficient cold air heating and purification via ventilation. Carbon nanotubes endow the membrane with high light absorption and thermal conversion capabilities, thereby sufficiently heating the approaching cold air. With the hierarchical structure formed by phase inversion, the thin upper skin of the composite membrane intercepts micropollutants via the size-sieving effect, whereas the finger-like pores and interpenetrating macrovoids inside the membrane ensure that the heated clear air passes through quickly. A proof-of-principle experiment indicated a cold airflow of 1 L/min across the membrane, yielding a temperature increase of ca. 37 °C as well as a PM 2.5 rejection always higher than 93%. Further antibacterial experiments demonstrated that the membrane effectively removed airborne bacteria. This multifunctional carbon nanotube-based photothermal membrane with specific microstructures not only improves the indoor living quality but also provides a sustainable development scheme to coordinate the relationship among energy utilization, building heating, and air purification.

Mountain-protection-mesh-inspired pSi@pPAN/CNTs composites as stable anode materials for lithium-ion batteries

Silicon (Si) is the most promising candidate for next-generation anode material of lithium-ion batteries. However, its commercial application is impeded by the poor cycling stability caused by the pulverization. Herein, we draw inspiration from mountain protection mesh and design a micrometer-scale porous core–shell structure via the phase inversion. The porous Si core's cavity can accommodate the volume expansion during lithiation, while the external mesh-like coating, composed of porous polyacrylonitrile (PAN) and conductive carbon nanotubes (CNTs), effectively restrains the outward expansion of Si. The synergistic effect of these components effectively enhances cycling stability, resulting in a capacity of 907.56 mAh/g at 1.0 A/g after 500 cycles. This study offers a scalable and cost-effective approach for the practical application of Si.

Modelling for Multiport Converter-based Hybrid Power supply for Renewable Energy Source Application

This research work deals with the design, modeling and technical evaluation of multiport modular converter based hybrid Power supply using solar PV for small village. The village’s maximum power demand is 50kvA, consisting of demands of twenty (20) households. The first converter in the proposed multiport system is a high frequency isolated DC-DC converter fed with HVDC link yielding an output voltage of 700vDC. The isolated DC-DC converter uses a medium frequency transformer with primary and secondary side converters in input-series output-parallel (ISOP) configuration. Also, the output of first converter is connected to a solar PV and battery system through a buck-boost converter. The second converter in the system is solar PV fed three phase modular inverter designed to have output AC line voltage of 0.415 kV. The three phase inverter is based on modular multilevel converter (MMC) with interleaved modulation techniques. A silicon carbide power MOSFETs, with model numbers CPM3-10000-0270(CREE) and SD11703 (Solitron) are used as a building blocks for isolated DC-DC converter. On the other hand, SiC -MOSFET with part number SCT3017AL (RHOM) is used as basic building block for modular inverter. A solar PV module with open circuit voltage of 85V and maximum power rating of 415W is used to feed the inverter. Different scenarios such as changes in load and changes in solar irradiance are used for critically evaluating the performances of the system under question. The output voltage THD, current distortions, changes in the converter output voltage, current magnitude and converter efficiency are used for performance evaluation of the system under consideration. Simulink/ PLECS (Piecewise Linear Electrical Circuit Simulation) combo simulation platform is used to model and simulate the system in question. Simulation results showed that the proposed multiport converter system can be a viable alternative to low frequency distribution transformer.
 Keywords: Multiport converter, MMC, DC-DC converter, Hybrid power Supply, Solar PV.

Pterostilbene lipid nanocapsules as a promising system for treatment of hepatocellular carcinoma: Formulation, characterization, and cellular/in vivo appraisal

Pterostilbene has shown very promising traits as a nutraceutical compound, especially in the field of cancer treatment. However, its poor aqueous solubility hinders its clinical applicability. The purpose of this work was to enhance the antitumoral activity of pterostilbene in hepatic cancer via encapsulation in lipid nanocapsules. Pterostilbene nanocapsules were prepared using the phase inversion technique. One gram of Kolliphor® HS 15 dissolved in 3 g of distilled water was added to 1 g of isopropyl myristate containing 150 mg Epikuron 200 and 100 mg pterostilbene under magnetic stirring, while applying three temperature cycles alternating between 55 and 85 °C for phase inversion to occur. Shock cooling of the dispersion was induced by introduction of 5 g of distilled water, followed by stirring for 30 min. The nanocapsules were characterized for the particle size, polydispersity index, zeta potential, entrapment efficiency, drug loading, morphology, antitumoral activity in HepG2 liver cancer cell line in terms of viability, assessment of cell death mode and cycle arrest, cellular localization assessment, and quantification of cellular uptake. The in vivo antitumoral activity of lipid nanocapsules was further verified using a chemically-induced hepatic cancer model using diethylnitrosamine and carbon tetrachloride. Several biochemical markers were quantified, followed by histopathological examination. Results displayed the potential of pterostilbene in treatment of liver cancer, with the enhancement of its therapeutic efficacy by encapsulation in lipid nanocapsules, as evidenced by further decreased levels of ALT, AST, AFP, Bcl2, VEGF, NF-kB, ERK, AKT, with concomitant increase in caspase3 level, while showing comparable histological features to the normal control group. Pterostilbene nanocapsules were proven promising in the treatment of hepatocellular carcinoma, deserving further preclinical and clinical evaluation.

MIL-101(Cr) incorporated hollow fiber membrane for rubber wastewater treatment using membrane bioreactor

The hollow fiber (HF) membrane in this study was modified using polyethersulfone (PES) and MIL-101(Cr) metal–organic framework (MOF) for the treatment of synthetic rubber effluent using an aerobic submerged membrane bioreactor (MBR). The phase inversion and wet spinning techniques were used for membrane preparation and to manufacture the MOF-incorporated HF membranes, respectively. The manufactured HF membranes were characterized using Field Emission Scanning Electron Microscopy (FESEM), Fourier Transform Infrared Spectroscopy (FTIR-KBR), Atomic Force Microscopy (AFM), X-Ray Diffraction (XRD), Tensile Strength (TS), and Water Contact Angle (WCA) studies. The MIL-101(Cr)/PES HF membrane has increased porosity by 14%, surface roughness increased by 38%, and surface hydrophilicity increased by 15% compared to the pure PES HF membrane. The results demonstrated that the higher hydrophilicity of the metal–organic framework (MOF) MIL-101(Cr) positively affected the HF membrane surface properties and performance in the bioreactor. Additionally, it was shown that the removal efficiency for total suspended solids (TSS), total dissolved solids (TDS), biological oxygen demand (BOD5), and chemical oxygen demand (COD) were 45.5%, 65.6%, 90%, and 94% respectively.