Search

In this work, we study the rheology of suspensions of polystyrene (PS) spheres at concentrations ranging from 8 to 66% (v/v) in a matrix of molten ethylene vinyl acetate copolymer (EVA) at temperatures spanning through the glass transition temperature of the PS spheres. As a result of the significant difference between the softening temperatures of these blend components, the melt order plays a crucial role in the generation of the blend morphology, rheology, and optimization of processing conditions. When the PS is rigid (below T g ), the suspensions showed significant Mullins and Payne effects, disappearing at higher temperatures where PS was sufficiently softened. The origin of these effects is postulated to be due to the extensive filler-filler contacts and radial alignment of the PS beads. Near the glass transition of PS, the PS spheres became deformable and viscosity of the suspension showed an unusual variation as a function of PS loading. The Krieger-Dougherty model was used to predict viscosity variation with volume fraction. We demonstrate that the deformability of the "solid" PS spheres significantly affects the reduced suspension viscosity at both intermediate volume fractions of 0.42 to 0.44, where there was an anomalous dip in viscosity, and at higher volume fractions beyond 0.60, where the increase in viscosity was not as prounounced as that for suspensions of rigid particles. [ABSTRACT FROM AUTHOR]

Membrane technology is a technique in water and wastewater treatment that has many advantages. This study focuses on the manufacture and characterization of cellulose acetate propionate (CAP) membranes using the phase inversion method. The CAP is preferable since it is a biopolymer that is environmentally friendly and cheap. The production of CAP membrane was carried out using phase inversion method, and varied in 3 different concentrations of CAP i.e., 13, 14, and 15% wt., with additional material of polyethylene glycol (PEG). The characterization was conducted using scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) analysis to determine its morphology, pores, and functional groups. The results show that the membrane containing 13% wt. CAP exhibits higher porosity with more macropores than a membrane with 14 and 15% wt. CAP. However, membranes with higher concentrations of CAP show more uniform pores and fewer macropores. FTIR analysis confirmed the presence of functional groups in the membrane such as C-O, -CH3, C=O, C-H, and – OH. It is also found that there is a shift in Wavenumber due to the increase in the concentration of CAP in each membrane. [ABSTRACT FROM AUTHOR]

This comparative study investigates the modification of polyvinylidene fluoride (PVDF) membranes with different nanoparticles (TiO2 or TiO2-based composites containing BiVO4 and/or CNT), using three distinct methods (blending, coating, and grafting) and polyvinylpyrrolidone (PVP). The objective was to enhance the photocatalytic and filtration performance for the separation of oil-in-water emulsions. Regarding the UV activity, the PVDF-TiO2/CNT/PVP-coated membrane presented the best performance. Overall, the addition of 2 wt.% CNT to the TiO2 notably enhanced the photocatalytic activity of the membranes for both UV and visible irradiations. Meanwhile, the presence of 2 wt.% BiVO4 was beneficial only for photocatalysis under visible light irradiation. Regarding the filtration of the oil-in-water emulsions, 2 wt.% CNT or BiVO4 addition resulted in the highest fluxes in the series of the PVDF-TiO2-grafted membranes. The presence of pore former PVP led to relatively high fluxes and photocatalytic activities for all series. Regarding the modification methods, coated membranes showed the highest photocatalytic efficiency and lowest fluxes. Grafted membranes showed relatively high photocatalytic efficiencies and the best filtration performances. [ABSTRACT FROM AUTHOR]

Liquid-liquid solvent extraction, commonly used for high purity Co(II) extraction, suffers from drawbacks such as environmental pollution and high cost. To overcome these challenges, a novel Cyanex 272 (bis(2,4,4-trimethyl pentyl)phosphinic acid, HCyanex) adsorptive membrane (CAM) was synthesized using the phase inversion method with varied Cyanex 272 loadings (0–52.5%) to extract Co(II) from cobalt-nickel mixed sulfate solution. Fourier transform infrared (FTIR) spectrometer, Scanning electron microscopy (SEM), and Energy dispersive X-ray spectroscopy (EDX) of as-prepared CAMs confirmed the successful and homogeneous blending of Cyanex 272 with poly(vinylidenefluoride) (PVDF), and increased pore sizes were observed with the addition of Cyanex 272. The highest Co (II) removal was achieved by the CAMs containing 33.2% weight percentage of Cyanex 272 to PVDF with a Langmuir sorption capacity of 1.42 mg/g. The extraction process for Co(II) and Ni(II) by CAMs was sensitive to pH and temperature, with an optimal separation factor of 209.5 at pH 6.8 and 75 °C. The adsorption process is endothermic. Additionally, the membrane exhibited excellent stability and durability, maintaining around 98% adsorption capacity after 20 cycles in the recycling process. These findings suggest that the as-prepared CAMs are a promising technology for the separation of Co(II) from Ni(II) in the recycling process of lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Herein, we report a micro-tubular protonic ceramic fuel cell with novel bio-inspired four-channel structure, which has a considerable maximum output power density of 231 mW cm−2 and good long-term stability. [ABSTRACT FROM AUTHOR]

Cellulose is a natural polymer contained in growing fibres, such as pineapple fibres. Cellulose can be modified into cellulose acetate, a modified polymer that can be used in the synthesis of a cellulose acetate/polyethylene glycol (CA/PEG) membrane. The phase inversion method was used in this study to produce CA/PEG membranes. Variations in polyethylene glycol (PEG) concentration with a ratio of 1:1 to cellulose acetate, where variations in PEG concentrations used are 2%, 5% and 8%. Acetone and dimethylformamide are used as organic solvents. Membrane morphological analysis using scanning electron microscopy (SEM) and functional group analysis using a Fourier transform infrared (FTIR) spectrometer were performed for membrane characterisation. The result of the synthesis of the CA/PEG membrane is in the form of a thin white layer. The characterisation results of the FTIR spectrometer showed the vibration of the carbonyl bond at wavenumber 1729 cm--1 and the vibration of the hydroxyl bond torque at the wave number 648 cm--1, where the vibration intensity decreased with each addition to the concentration. The results of SEM characterisation show that the increase in PEG concentration increases the percentage porosity of the membrane. The membranes with 2%, 5% and 8% PEG have porosity percentages of 51.54%, 68.70% and 73.50%, respectively. As the membrane with 2% PEG has the lowest percent porosity, it has more potential in removing or filtering solutes from a fluid. [ABSTRACT FROM AUTHOR]

The fabrication of membranes for water desalination and wastewater treatment is an important strategy to overcome water quality problems worldwide. Herein, the influence of the presence of the poly(amidoamine) dendrimer (PAMAM) on the performance of the cellulose acetate (CA) membrane was investigated. Halloysite nanotube (HNT) was functionalized with the third generation of PAMAM dendrimer and incorporated into the CA membrane by phase inversion process to improve the properties of the membrane. The functionalized HNTs and composite membranes were characterized in detail: Fourier-transform infrared spectroscopy (FTIR), Atomic force microscopy (AFM), contact angle measurements, zeta potential, thermogravimetric (TGA) analyses, and field emission scanning electron microscopy (FE-SEM). A dead-end filtration system examined the performance of the incorporated cellulose acetate membrane. Based on the results, the membrane permeability, salt rejection, and antifouling properties were improved due to the addition of hydrophilic HNTs- PAMAM nanocomposite in the membrane casting solution. The loading of 1wt% of HNTs/PAMAM was optimized as filler composition. It showed salt rejection of 91% and 75.6% for sodium sulfate and magnesium chloride respectively along with the maximum porosity (82%), antifouling performance (85%), reversible fouling ratio (45%), and the lowest contact angle (~ 32). [ABSTRACT FROM AUTHOR]

Water pollution caused by heavy metal ions (HMI) and dyes is a global issue challenging current solutions. Membrane filtration shows promise, yet faces limitations like fouling and low flux. This study proposes a new membrane by incorporating graphene oxide zinc oxide (GO‐ZnO) nanocomposites into a polyethersulfone (PES) matrix to overcome these challenges. The synthesized membrane exhibits strong antimicrobial activity, crucial for water treatment, and high efficiency in removing HMIs (Cu2+ and Ni2+) and dyes (BB9 and EBT) from water samples and industrial wastewater. Characterization via FTIR and FESEM confirms its chemical composition and morphology, while contact angle measurements assess its hydrophilicity. Mechanical strength tests ensure durability. Overall, the membrane demonstrates exceptional antimicrobial activity, pollutant removal efficiency, and mechanical robustness, highlighting the potential of integrating GO‐ZnO nanoparticles into PES membranes for water treatment. Highlights: Synthesis of innovative PES membrane embedded with GO‐ZnO for durable and fast energy‐saving filtration.Thorough Membrane Characterization and its various applications with mechanisms.Efficient Heavy Metal and Dye Removal, Inherent Antibacterial Prowess. [ABSTRACT FROM AUTHOR]

This work is primarily focused on overcoming the limitations of polymeric membranes in achieving the balance between permeability and selectivity of the separation performance. The filler, Zeolitic imidazole framework -67 (ZIF-67) nanoparticles were synthesised in cubical morphology using hexadecyltrimethylammonium bromide (CTAB) as a surfactant via the wet-chemical method. The uniform particles with particle sizes ranging between 120–180 nm were incorporated into the polyvinylidene fluoride (PVDF) matrix to fabricate mixed matrix membranes via the phase inversion method. These mixed matrix membranes were systematically characterised to confirm the chemical, structural and morphological properties of the materials and membranes. Furthermore, the membranes showed a 56.5% improvement in their mechanical properties. The results confirm that 5 wt.% ZIF-67/PVDF membrane showed the best separation results compared to its pure counterpart. The permeability of H₂ gas was reported to be 1,094,511 Barrer, with selectivities of 3.03 for H₂/CO₂ and 3.06 for H₂/N₂. This represents a 210.6% increase in the permeability of H₂ gas. These results demonstrate the influence of ZIF-67 loading in the PVDF polymer matrix along with the potential of ZIF-67/PVDF mixed matrix membranes in the field of hydrogen separation and purification. [ABSTRACT FROM AUTHOR]

Polymer coatings are emerged as promising candidates for zinc anode artificial solid electrolyte interphase (ASEI) owing to their barrier effect and zincophilicity. However, the poor ionic conductivity of conventional polymer coatings limits their application. Herein, inspired by epidermis function, a porous poly(methylmethacrylate) (PMMA) coating is fabricated to stabilize Zn anode via a novel phase inversion method. The modified Zn anode delivers a remarkable lifespan of over 4000 h at 1 mA cm−2, 1 mAh cm−2, and 120 h at 20 mA cm−2, 20 mAh cm−2 in symmetrical cells. Moreover, porous PMMA‐Zn||NVO full cell also exhibits an excellent cycling stability over 500 cycles at 1 A g−1 as well as an ultralong lifespan exceeding 5000 cycles at 5 A g−1. The excellent cycling stability and rate performance are mainly attributed to the avoided side reactions by the coating protection, as well as the enhanced diffusion and reaction kinetics derived from the good zincophilicity and porous structure of porous PMMA. The facile and universal method for fabricating porous polymer ASEI provides a new insight for the application of conventional polymer materials in Zn anode protection. [ABSTRACT FROM AUTHOR]

Designing and optimizing the pore structure of porous carbon electrodes is essential for diverse energy storage systems. In this study, an innovative approach spray phase‐inversion strategy was developed for the rapid and efficient fabrication of controlled porous carbon aerogel. Moreover, the aggregation structure of polyacrylonitrile is controlled by adjusting the Hansen's solubility parameter, thereby regulating the electrode material structure. Furthermore, the theoretical analysis of the spray phase‐inversion process revealed that this regulation process is jointly regulated by solvent hydrodynamic diameter and phase‐inversion kinetics. Through optimization, a novel porous carbon material was obtained that exhibited excellent performance as an electrode material. When utilized in supercapacitors for energy storage, it demonstrated a high specific capacitance of 373.1 F g−1 in a 6 M KOH electrolyte solution. Simultaneously, it has been observed that the preparation strategy for porous electrodes offers notable advantages in terms of excellent designability, broad universality, simplicity, and high efficiency, thereby holding promise for large‐scale fabrication of diverse porous electrode materials and various types of electrodes for diverse energy storage applications. [ABSTRACT FROM AUTHOR]

In the article, the structure and characteristics of membranes made on the basis of polyethersulphone (PES5900) are studied. The membranes were fabricated by the wet phase inversion method using the solvents – dimethylformamide (DMF), dimethylacetamide (DMAc), and dimethylsulphoxide (DMSO). Polyvinylpyrrolidone (PVP) with different molecular weight (Mw) PVP10, PVP40 were added as pore-forming agents in the dope solution to modify the morphological, physical, permeation, and separation properties of the membranes. The structure and characteristics of the membranes were investigated by scanning a probe microscope and experimentally using a laboratory tangential microfiltration module. The porosity and performance of the membrane fabricated from the PES/DMSO/water system are higher than those of membranes derived from the PES/DMAc/water and PES/DMF/water systems. The molecular weight (Mw) of PVP is another important factor affecting the porous structure of polymer membranes. It was shown that the addition of low molecular PVP10 leads to the formation of a porous membrane with higher performance than that of high molecular PVP40. It was shown that the addition of PPV to the solution for casting membranes ensures the formation of membranes with different morphology, properties, and characteristics thanks to their influence on the stability of the solution, hydrophilicity, and viscosity. [ABSTRACT FROM AUTHOR]

Waterborne polyurethane asphalt emulsion (WPUA) is an environmentally friendly bituminous material, whose performance is highly dependent on the phase structure of the continuous phase. In this paper, WPUAs in the vicinity of phase inversion were prepared using waterborne polyurethane (WPU) and asphalt emulsion. The chemical structures, thermal stability, dynamic mechanical properties, phase-separated morphology and mechanical performance of WPUAs were studied. Fourier-transform infrared (FTIR) spectra revealed that there are no –NCO bonds in either the pure WPU or WPUAs. Moreover, the preparation of WPUA is a physical process. The addition of WPU weakens the thermal stability of asphalt emulsion. WPU improves the storage modulus of asphalt emulsion at lower and higher temperatures. The glass transition temperatures of the WPUA films are higher than that of the pure WPU film. When the WPU concentration increases from 30 wt% to 40 wt%, phase inversion occurs; that is, the continuous phase shifts from asphalt to WPU. The WPUA films have lower tensile strength and toughness than the pure WPU film. However, the elongations at break of the WPUA films are higher than that of the pure WPU film. Both the tensile strength and toughness of the WPUA films increase with the WPU concentration. Due to the occurrence of phase inversion, the elongation at break, tensile strength and toughness of the WPUA film containing 30 wt% WPU are increased by 29%, 250% and 369%, respectively, compared to the film with 40 wt% WPU. [ABSTRACT FROM AUTHOR]

In the present work, we demonstrate that zero‐shear viscosity is a sensitive rheological function to detect phase inversion in immiscible binary polymer blends characterized by a viscosity ratio larger than one. The phase inversion of poly(propylene) (PP)/low‐density poly(ethylene) (LDPE) and poly(styrene) (PS)/LDPE, at various compositions, was assessed via our novel approach. For both blends, three distinctive regions could be determined through zero‐shear viscosity measurements; the LDPE matrix, the co‐continuous phase, and the PS or PP matrix. For PP/LDPE blends, the co‐continuous structure was between 50 and 75 wt.% PP, and for PS/LDPE blends the co‐continuous structure was between 45 and 75 wt.% PS, in agreement with scanning electron microscopy analysis, empirical model predictions, and literature data. Highlights: Phase inversion revealed via viscosity measurements.Limitations of linear viscoelastic models for immiscible blends assessed. [ABSTRACT FROM AUTHOR]

A voltammetric sensor based on a glassy carbon electrode modified with a chitosan, Carboblack C graphitized carbon black, and molecularly imprinted polyarylene phthalide composite is developed for the selective detection of antibiotic clarithromycin. The polyarylene phthalide used for modification contains diphenylenethio- and diphenylene oxide fragments in a 1 : 2 ratio in the main polymer chain. Clarithromycin-imprinted polyarylene phthalide was obtained using the phase inversion method. The composition and morphology of the modifying coating were investigated by IR spectrometry and scanning electron microscopy. The electrochemical and analytical characteristics of the sensor were investigated by electrochemical impedance spectroscopy, cyclic voltammetry, and differential pulse voltammetry. Optimal conditions for recording the analytical signal were selected. Using [Fe(CN)6]3−/4− as a probe, the linear range of the detected concentrations was found to be 1 × 10–7–5 × 10–4 M with a limit of detection of 5.3 × 10–8 M. Using a clarithromycin-imprinted polymer enhances the sensor sensitivity by nearly tenfold compared to the nonimprinted polymer. The proposed sensor was tested using urine, blood plasma, and various food samples (meat, milk), the recovery values were 90–96, 80, and 92%, respectively, with relative standard deviations not exceeding 10% in all cases. [ABSTRACT FROM AUTHOR]

This study focuses on the synthesis of a PVDF membrane using DMAc as the solvent through a combination of evaporation-induced phase separation (EIPS) and non solvent-induced phase separation (NIPS) techniques. The experimental findings underscore the significant role of thermodynamic and kinetic parameters in the phase inversion process, influencing the surface and transport properties of the resulting membrane. By precisely controlling the combined processes of EIPS and NIPS, a customized membrane with specific characteristics such as a rough surface (roughness of up to 725.9 µm) and hydrophobicity (water contact angle up to 117°) was successfully achieved. The synthesized membrane exhibits good membrane properties (total porosity ≥ 50%, mean pore size ranging from 0.01 to 0.35 μm) with well-connected pores. To assess its quality, the membranes permeate flux, reaching up to 12.8 kgh−1 m−2, and salt rejection rate of 99.8% were evaluated using Vacuum Membrane Distillation (VMD). Furthermore, a fouling study was conducted to investigate the impact of operating time on membrane performance, revealing a negligible decline in membrane fouling over a 200-h run. [ABSTRACT FROM AUTHOR]

The starting point for the preparation of polymeric membranes by phase inversion is having a thermodynamically stable solution. Ternary diagrams for the polymer, solvent, and non-solvent can predict this stability by identifying the phase separation and describing the thermodynamic behavior of the membrane formation process. Given the lack of data for the ternary system water (H2O)/hydrochloric acid (HCℓ)/polyamide 66 (PA66), this work employed the Flory–Huggins theory for the construction of the ternary diagrams (H2O/HCℓ/PA66 and H2O/formic acid (FA)/PA66) by comparing the experimental data with theoretical predictions. Pure polymer and the membranes produced by phase inversion were characterized to provide the information required to create the ternary diagrams. PA66/FA and PA66/HCℓ solutions were also evaluated regarding their classification as true solutions, and the universal quasi-chemical functional group activity coefficient (UNIFAC) method was used for determining non-solvent/solvent interaction parameters (g12). Swelling measurements determined the polymer/non-solvent interaction parameter (χ13) for H2O/PA66 and the solvent/polymer interaction parameter (χ23) for PA66/FA and PA66/HCℓ. The theoretical cloud point curve was calculated based on “Boom’s LCP Correlation” and compared to the curve of the experimental cloud point. The ternary Gibbs free energy of mixing and χ23 indicated FA as the best solvent for the PA66. However, for HCℓ, the lower concentration (37–38%), volatility, and fraction volume of dissolved PA66 (ϕ3) indicated that HCℓ is also adequate for PA66 solubilization based on the similar membrane morphology observed when compared to the PA66/FA membrane.

Polyethersulfone (PES) membranes containing 4‐fluorophenyl sulfone‐terminated poly(diallylpiperidinium hexafluorophosphate)‐sulfonated poly(ethylene terephthalate) polyelectrolyte complexes (PECs) were obtained via phase inversion using three different methods that enabled the complexation of polyelectrolytes (PELs) to occur before, after, and during membrane formation. Atomic force microscopy‐infrared spectroscopy analysis revealed varying concentrations of the polyanion depending on the preparation method and confirmed the presence of PECs in the membranes, highlighting an increase in surface roughness. Zeta potential measurements demonstrated positive surface charges for the membrane comprising PES and the polycation. The reduction in zeta potential in PEC membranes corresponded with the neutralization of positive groups by sulfonated poly(ethylene terephthalate. Scanning electron microscopy micrographs depicted surface imperfections in PEC membranes, emphasizing the influence of PECs on membrane surfaces. The water contact angle decreased, indicating increased hydrophilicity in PEC membranes. Additionally, dye adsorption results showcased significant adsorption, with the membranes absorbing at least 60% of Remazol Red from an aqueous solution. Notably, the Blend membrane outperformed others, exhibiting an exceptional adsorption rate exceeding 92%. [ABSTRACT FROM AUTHOR]

In order to address the safety concerns of conventional carbonate liquid electrolytes in lithium (Li) batteries, porous gel polymer electrolytes (GPEs) can encapsulate the solution while providing good electrolyte–electrode contact. In this work, a GPE is designed and fabricated with multifunctional exfoliated two-dimensional (2D) hexagonal boron nitride nanosheets (BNs), leading to improved thermal stability, ionic conductivity, Li+ transference number, mechanical strength, and dendrite-suppressing properties for Li metal batteries. Through phase inversion, a high porosity and electrolyte uptake are achieved while maintaining a stable film structure. Utilizing a binary polymer mixture of polyvinylidene fluoride (PVDF) and poly-(ethylene oxide) (PEO) doped with exfoliated BN flakes, the final BN-GPE at 3.6 wt % BN can effectively suppress dendrite growth through multiple charge/discharge cycles with a high ionic conductivity of 3.03 × 10–3 S/cm at ambient conditions while showing a high Li transference number of 0.60. The Li metal battery cell performance with this GPE demonstrates a strong initial capacity at 82.9 mAh/g at 0.5C and improves capacity over the undoped GPE by 22% after 45 cycles. [ABSTRACT FROM AUTHOR]

Flexible, lead-free piezoelectric nanogenerators are gaining prominence as viable alternatives with remarkable potential in the backdrop of increasing demand for sustainable energy solutions, particularly in the field of microelectronic systems and sensing technologies. In this context, the synergistic impact of utilizing reduced graphene oxide (rGO) nanosheets decorated with zinc oxide (ZnO) nanorods, in conjunction with a low-temperature phase-inversion technique aimed at augmenting the polar β-phase of poly-(vinylidene fluoride) (PVDF) was explored. The nanofiller concentrations of rGO and ZnO were systematically varied to ascertain the optimal concentration in the PVDF matrix. These optimal concentrations were further used to fabricate PVDF/ZnO/rGO hybrid and PVDF/ZnO-decorated rGO nanocomposites. Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), and differential scanning calorimetry (DSC) characterizations were employed to examine the electroactive crystal phase in synthesized nanocomposites, confirming enhancement in polar β-phase and crystallinity, thereby improving piezoelectric, dielectric, and ferroelectric properties of the nanocomposites as confirmed by a dielectric broadband spectrometer (BDS) and piezoresponse force microscopy (PFM). A comparative analysis of optimized nanocomposites supplemented with related characterizations was performed to assess their piezoelectric performance. Additionally, systematic variations in force and frequency were carried out to understand their correlation with the piezoelectric performance of PENGs. The optimized PENG showcased the exceptional piezoelectric energy harvesting potential, generating an open circuit voltage of 23 V (at 1 Hz and 1 N), 98 V (at 5 Hz and 10 N), and 153 V (at 15 Hz and 50 N). Further, the PENG produced an instantaneous power density of ∼28 μW/cm2, charged a range of capacitors, sensed human body motions, successfully illuminating 50 LEDs in series and 36 in combination of series and parallel connections. This fabricated PENG henceforth showcases the immense potential for energy harvesting applications. [ABSTRACT FROM AUTHOR]