Macroporous Structure Research Articles

Comprehensive Approach to Evaluating the Macro- and Micropore Structures of Textile Materials

Introduction. The assessment of the macro- and microporous structure of textile fabrics is increasingly relevant for predicting their permeability, dyeability, and decorative potential. This evaluation plays a crucial role in determining the hygienic properties of clothing materials, optimizing dyeing and finishing processes, and assessing the filtration capabilities of technical fabrics in various dispersed media.Problem Statement. Challenges persist in accurately predicting the permeability of textile fabrics, as well as in determining the optimal parameters for dyeing and finishing processes.Purpose. The purpose of this research is developing a rapid, cost-effective, and accurate method to evaluate the macro- and microporous structure of textile materials is essential for assessing their permeability and suitability for dyeing and fi nishing processes.Materials and Methods. To study the porous structure of textile fabrics, we select the fabrics that varied in the thread structure — yarn produced by traditional and shortened methods — and in the fibrous composition. The first fabric is made from complex polyamide threads in a plain weave, the second from twill-woven polyester fiber yarn, and the third differs from the second in the structure of the weft thread. The macro- and microporous structures of these textile fabrics have been assessed by means of drying methods and sorption thermograms.Results. The micro- and macroporous structures of textile fabrics made from polyamide threads and polyester fibers have been compared. It has been found that the fabric made from polyamide threads exhibits a significantly higher sorption capacity than the fabric made from polyester fibers. This finding suggests that the fabrics made from polyamide threads possess a more developed microporous structure. This fact enhances their dyeing and decorating capabilities as compared with the fabrics made from polyester fibers. A comprehensive approach, utilizing both drying methods and sorption thermograms, has been employed to evaluate the macro- and microporous structures of the textile fabrics. Conclusions. The proposed comprehensive approach enables comparative studies of various textile materials, allowing for the refinement of technological processes for dyeing and decorating, as well as the identification of potential applications for these materials.

N, P co-Doped Hard Carbon Anodes for High-Performance Lithium-Ion Batteries with Enhanced Capacity Retention and Cycle Stability.

Compared to the traditional graphite anode, heteroatom-doped polymer carbon materials have high capacity retention due to their high porosity and porous structure. Therefore, they have great potential for application in lithium-ion battery (LIB) anodes. In this work,an N, P co-doped precursor polymer material (MBPp), synthesized via a one-pot method using bisphenol-A (C-source), melamine (N-source), and 9,10-Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (P-source). The resulting N, P-co-doped hard carbon materials (MBPs) were prepared at various pyrolysis temperatures, yielding microporous, mesoporous, and macroporous structures. MBP materials demonstrated excellent electrochemical performance as LIB anodes. Notably, MBP-900 achieved a reversible capacity of 262 mAh g-1 at 1000 mA g-1 (in 0.005-2.0 V voltage range) with a capacity retention rate of 97.2% after 1000 cycles. These findings highlight the significance of MBP materials, which possess numerous defects, large layer gaps, and excellent cycle stability, in advancing the development of polymer anode materials for LIBs.

Enhanced Photocatalysis via Inverse Opal Structures: Synthesis and Characterization of TiO2/ZnO and ZnO/TiO2 Composites Using Plasma-Enhanced ALD

Inverse opals (IO) based functional materials show potential in photocatalysis due to their unique light interaction properties. This study presents a low-temperature plasma-enhanced atomic layer deposition (PEALD) method for synthesizing TiO2, ZnO, and composite IOs using a polystyrene nanoparticle-based opal template. We comprehensively characterized the obtained materials using SEM-EDX, TSEM, TG, FTIR, XRD, Raman, ellipsometry, photoluminescence (PL), and UV-Visible spectroscopy. SEM analysis confirmed the successful formation of PEALD IOs with a periodically ordered structure, enabling conformal coating while preserving their original architecture. XRD and Raman analysis also confirmed that the IOs consisted of anatase for TiO2 and hexagonal wurtzite for ZnO. UV-Vis reflectance spectroscopy revealed strong UV absorption and modified photonic bandgaps (PBGs) for all materials. The bare and composite IOs exhibited PBGs in the visible region, suggesting that the arising "slow photon" effect might enhance photocatalysis. This study explored the photocatalytic degradation of 4-Nitrophenol (4-NP) and Rhodamine 6G (Rh6G) using pristine and composite IO photocatalysts under UV and visible light irradiation. Pristine TiO2 and ZnO IOs demonstrated superior performance for 4-NP degradation under UV light. This can be attributed to two key factors: their highly ordered macroporous structure (with a large surface area for efficient dye adsorption, and their band gaps (3.0 eV for TiO2 and 3.2 eV for ZnO) that enable strong absorption of UV light photons for effective pollutant degradation. Conversely, composite IOs (TiO2/ZnO and ZnO/TiO2) displayed higher activity for both test molecules under visible light due to a synergistic effect between bandgap harmonization and the PBG effect.

A sustainable lignin-clay nano-absorbent for highly efficient methylene blue removal

Water pollution caused by toxic dyes such as methylene blue (MB) has become a bottleneck for recycling or reusing enormous industrial wastewater. Designing a green and cost-effective bio-absorbent for the highly efficient removal of MB from wastewater is crucial but remains a great challenge. In this study, abundant, inexpensive, and environmentally benign lignin and bentonite were used as starting materials, and quaternary and amphiphilic lignin as a network macromolecule was designed to be inserted into the galleries of the stacked bentonite clay to prepare lignin-bentonite nanohybrids. The specific surface area of the modified nano-absorbent was significantly increased to 45.60 m2/g and owned a type II-like isothermal mechanism. The absorbent showed a maximum removal of MB of 99.7 % at neutral pH and room temperature with a maximum adsorption capacity of 822.22 mg/g, demonstrating the potential of an excellent adsorbent. The MB adsorption process fits well with both Langmuir and Freundlich isotherm models, the adsorption mechanism includes strong electrostatic attraction between absorbent and MB, and physical adsorption in a complicated monolayer and multiple macroporous structures. This study leverages the economic and environmental benefits of lignin and bentonite clay to prepare a cost-effective bio-absorbent for efficient removal of MB from aqueous solutions.

Hypermobility of a Catastrophic Earthquake-Induced Loess Landslide

Landslide mobility refers to how far and fast a landslide can move downslope. It controls landslide impact areas and damage power. Highly mobile landslides are often initiated on slopes steeper than 30°. However, on 18 December 2023, an earthquake-induced landslide (35°52′54″N, 102°51′10″E) exhibited extraordinary mobility, with an overall travel angle of 1.5°, breaking an on-land landslide record. The landslide originated on a gentle slope (3.6°), eroded an earth dam along its travel path, and finally destroyed 51 houses and claimed 20 lives. Remote sensing and field surveys were conducted to provide morphological characteristics of the hazard chain. A numerical program, EDDA (Erosion–Deposition Debris Flow Analysis), was employed to reproduce the flow dynamics and investigate the causes of hypermobility. The findings reveal three primary causes of hypermobility: (1) liquefaction of the saturated silty loess stratum due to the combined effects of irrigation activity and seismic loading, (2) the loose and macro-pore structure of loess, and (3) confined topography and icy channel bed. The mechanisms revealed have broad implications for understanding fluidized mass movements on gentle slopes in seismically active regions.

Tuning porosity of macroporous hydrogels enables rapid rates of stress relaxation and promotes cell expansion and migration

Extracellular matrix (ECM) viscoelasticity broadly regulates cell behavior. While hydrogels can approximate the viscoelasticity of native ECM, it remains challenging to recapitulate the rapid stress relaxation observed in many tissues without limiting the mechanical stability of the hydrogel. Here, we develop macroporous alginate hydrogels that have an order of magnitude increase in the rate of stress relaxation as compared to bulk hydrogels. The increased rate of stress relaxation occurs across a wide range of polymer molecular weights (MWs), which enables the use of high MW polymer for improved mechanical stability of the hydrogel. The rate of stress relaxation in macroporous hydrogels depends on the volume fraction of pores and the concentration of bovine serum albumin, which is added to the hydrogels to stabilize the macroporous structure during gelation. Relative to cell spheroids encapsulated in bulk hydrogels, spheroids in macroporous hydrogels have a significantly larger area and smaller circularity because of increased cell migration. A computational model provides a framework for the relationship between the macroporous architecture and morphogenesis of encapsulated spheroids that is consistent with experimental observations. Taken together, these findings elucidate the relationship between macroporous hydrogel architecture and stress relaxation and help to inform the design of macroporous hydrogels for materials-based cell therapies.

Preparation of monolithic silica HPLC columns with truss-structured skeletons and embedded surfactant-templated mesopores

AbstractMonolithic macro/mesoporous silica gels have been prepared via a sol-gel process using triblock copolymer Pluronic P123 (EO20PO70EO20) as a structure-directing agent. In this synthesis, P123 not only induces phase separation to form macroporous structure but also acts as a supramolecular template to form mesopores with precisely controlled shape and size. Obtained was a monolithic silica composed of continuous truss-like columnar skeletons in which cylindrical mesopores are arranged in a 2D-hexagonal symmetry. These monolithic silica gels have extremely high porosity approaching 90% and exhibited high specific surface area and sharp pore size distribution as revealed by N2 sorption measurements. Combinations of the initial composition and the post-gelation treatment on wet gels allowed the control of physical properties of meso- and macropore structures. The monolithic HPLC columns prepared using these silica gels surface-modified by ODS (octadecylsilyl) ligands gave as many as 140,000 theoretical plates/m for the separation of alkylbenzenes in a reversed-phase mode. Very weak dependence of height equivalent to theoretical plate, H, on the mobile phase velocity was also recognized in comparison with conventional particle-packed columns. Graphical Abstract

Application of electrospinning and 3D-printing based bilayer composite scaffold in the skull base reconstruction during transnasal surgery

Skull base defects are a common complication after transsphenoidal endoscopic surgery, and their commonly used autologous tissue repair has limited clinical outcomes. Tissue-engineered scaffolds prepared by advanced techniques of electrostatic spinning and three-dimensional (3D) printing was an effective way to solve this problem. In this study, soft tissue scaffolds consisting of centripetal nanofiber mats and 3D-printed hard tissue scaffolds consisting of porous structures were prepared, respectively. And the two layers were combined to obtain bilayer composite scaffolds. The physicochemical characterization proved that the nanofiber mat prepared by polylactide-polycaprolactone (PLCL) electrospinning had a uniform centripetal nanofiber structure, and the loaded bFGF growth factor could achieve a slow release for 14 days and exert its bioactivity to promote the proliferation of fibroblasts. The porous scaffolds prepared with polycaprolactone (PCL), and hydroxyapatite (HA) 3D printing have a 300 μm macroporous structure with good biocompatibility. In vivo experiments results demonstrated that the bilayer composite scaffold could promote soft tissue repair of the skull base membrane through the centripetal nanofiber structure and slow-release of bFGF factor. It also played the role of promoting the regeneration of the skull base bone tissue. In addition, the centripetal nanofiber structure also had a promotional effect on the regeneration of skull base bone tissue.

Functional Three-Dimensional Zeolitic Imidazolate Framework with an Ordered Macroporous Structure for the Isolation of Extracellular Vesicles.

Extracellular vesicles (EVs) and their cargoes are increasingly being recognized as noninvasive diagnostic markers, necessitating the isolation of EVs from complex biological samples. Herein, a distearoyl phospholipid ethanolamine-functionalized single-crystal ordered macroporous three-dimensional zeolitic imidazolate framework (SOM-ZIF-8-DSPE) was developed, which combines the surface charge interaction of ZIF-8 with the synergistic effect of DSPE insertion into the phospholipid membrane of EVs to improve the isolating selectivity of EV capture. The materials have porous structures larger than 300 nm in diameter, providing enough space and active sites to trap EVs. Benefiting from this feature, the entire isolation process takes only 10 min and is well compatible with the subsequent analysis of RNA in EVs. Consequently, 10 upregulated miRNA of plasma EVs in the primary colorectal cancer (pCRC) patients is found over the healthy donors, and 6 upregulated miRNA of plasma EVs in the metastatic colorectal cancer (mCRC) patients over pCRC patients. These findings suggest that the isolation of EV-based SOM-ZIF-8-DSPE is a promising strategy to identify biomarkers for disease diagnosis, such as miRNAs in plasma EVs for the early detection of CRC.

Insights into the pore structure effect on the mass transfer of fuel cell catalyst layer via combining machine learning and multiphysics simulation

Analysis of the catalytic layer (CL) pore structure and three-phase (electron phase, proton phase, and reactant phase) mass transfer in high-temperature polymer electrolyte membrane fuel cell (HT-PEMFC) is critical for improving concentration polarization and optimizing performance. However, there is a lack of studies on the pore structure’s impact on the catalytic layer three-phase mass transfer. In this work, the influence of pore structure on catalytic layer three-phase mass transfer and multiphysics distribution was investigated by combining machine learning and multiphysics simulation. Among many key factors investigated by machine learning that impact the performance of catalytic layer, porosity emerges as the primary influencing factor. Porosity accounts for 32.7 % of the electric potential drop, with macro/micro porosity contributing 27.6 % and 5.1 %, and 32.8 % of the current density, with macro/micro porosity contributing 15.6 % and 17.2 %. Furthermore, the macropore structure has a much greater influence on the performance of the catalytic layer compared to the micropore structure. Moreover, the simulation results demonstrated that porosity has a great influence on three-phase mass transfer, the oxygen molarity increases with increasing porosity. The electric potential difference increases exponentially as porosity increases. The relationship between current density and porosity is a volcanic relationship, which can be expressed as a quadratic polynomial function. The mesoscopic pore-scale model (PSM) with an εeff of 0.502 (εmic of 0.2 and εmac of 0.378) exhibits the highest mean current density at 619.526 mA/cm2@0.5 V, attributed to a more uniform and efficient three-phase transfer path. The accuracy of the mesoscopic pore-scale model and the polynomial equation is further confirmed through corresponding experiments. The experiment results show that the current density decreased as the εeff increased from 0.682 to 0.702, which aligns with the theoretical predictions of the PSM model and polynomial equation. These studies are valuable for comprehending the internal three-phase mass transfer behavior and optimizing the catalytic layer pore structure to enhance HT-PEMFC performance.

SUPERSOFT SPONGE-LIKE CRYOGEL AS AN IMPLANT TO TREAT GLIOBLASTOMA

Abstract AIMS Create cylindrical cryogels with well-defined size. Investigate clemastine drug loading capicaty and drug release patterns. Investigate in vitro and in vivo safety and antitumor efficacy. METHOD A 3D printed template was designed and printed to make cylindrical shape cryogels. The morphology of cryogels was characterized by bright field photos, SEM, FTIR and confocal microscopy photos. The mechanical property was evaluated by uniaxial compression tests. The orthotropic glioblastoma tumor model was established by engrafting BT12 human glioblastoma stem cells intracerebrally into immunocompromised nude mice. The tumor was surgically removed after two weeks and the cryogel was implanted into the resection cavity. Animals were euthanized after two weeks, and their brains were collected for the immunohistochemistry. RESULTS Cylindrical cryogels were prepared to exactly fit the biopsy resection cavity in the mouse glioblastoma tumor resected model. The macropore structure in the cryogel was observed under confocal microscopy. Young’s modulus of the cryogel was only 1.6 kPa. The loading capacity of clemastine in one cryogel was more than 100 μg. Clemastine could be sustained released for around a week. In vitro cell viability studies showed that empty cryogels were not toxic to the tumor cells and drug loaded cryogels killed the tumor cells in a time and concentration dependent manner. In vivo studies further confirmed that cryogels could be safely implanted into the brain. Although the implantation of clemastine loaded cryogels did not prevent the growth of the primary tumor, it reduced the amount of invasion tumor cells compared with the mice only resected the tumor. CONCLUSION Cryogels were easily created by the 3D printed templates. The soft material avoided mechanical mismatch with the brain tissue. The cryogel did not show any toxicity in in vitro and in vivo studies, which indicated it would be a promising material to be implanted into the brain.

A chitosan macroporous hydrogel integrating enrichment, adsorption and delivery of blood clotting components for rapid hemostasis

Traditional hemostatic hydrogels face considerable limitations in achieving rapid control of severe bleedings, a crucial factor in reducing casualties in both military and civilian settings. This study presents a chitosan-based hemostatic hydrogel with interconnected secondary macropores designed to enhance interactions with blood clotting components by reducing diffusion resistance and increasing contact area. The macropores were created using a straightforward process involving NaOH-mediated SiO2 template dissolution and NH3 generation. The resulting macroporous structure increased the hydrogel's overall porosity without compromising its viscoelasticity. Functional studies demonstrated that the macroporous hydrogel effectively concentrated and adsorbed blood clotting components, while also facilitating the delivery of artificially embedded clotting factor to further expedite clot formation. These combined actions resulted in improve hemostatic efficacy, reducing whole blood clotting time by over 94 % in vitro. Furthermore, in vivo studies using rat tail amputation and liver injury models showed a reduction in blood loss by over 65 % and a decrease in bleeding time by over 70 %. Additionally, the porous chitosan hydrogel exhibited minimal biotoxicity and promoted biodegradability in vivo. In conclusion, this work introduces a macroporous chitosan-based hemostatic hydrogel with great potential for rapid hemorrhage control.

Food dye adsorption in single and ternary systems by the novel passion fruit peel biochar adsorbent

This study evaluated the passion fruit peel biochar (PFPB) as a novel adsorbent for synthetic food dyes indigotine blue (IB), tartrazine yellow (TY), and ponceau 4R (P4R) removal in single and ternary systems. A macroporous structure and a predominance of basic groups characterized PFPB. The pH study revealed better adsorption at pH 2.0. The response surface methodology optimization for adsorbent dosage and temperature predicted removal efficiencies of 100 % for IB, 79.8 % for TY, and 84.4 % for P4R. Elovich and Redlich-Peterson models better described kinetic and equilibrium, respectively, suggesting the contribution of chemical interactions. Thermodynamic data revealed endothermic, with an inordinate degree and spontaneous adsorption. In the ternary systems, antagonistic effects of interaction were noticed. The adsorption of synthetic effluents showed promising results with removal efficiencies of 99.6 % (IB), 60.2 % (TY), and 51.8 % (P4R). Therefore, we concluded that PFPB is a potential alternative low-cost synthetic food dye removal adsorbent.

Electrospun "Hard-Soft" Interpenetrating Nanofibrous Tissue Scaffolds Facilitating Enhanced Mechanical Strength and Cell Proliferation.

"Soft" hydrogel-based macroporous scaffolds have been widely used in tissue engineering and drug delivery applications due to their hydrated interfaces and macroporous structures, but have drawbacks related to their weak mechanics and often weak adhesion to cells. In contrast, "hard" poly(caprolactone) (PCL) electrospun fibrous networks have desirable mechanical strength and ductility but offer minimal interfacial hydration and thus limited capacity for cell proliferation. Herein, we demonstrate the fabrication of interpenetrating nanofibrous networks based on coelectrospun PCL and poly(oligoethylene glycol methacrylate) (POEGMA) nanofibers that exhibit the mechanical benefits of PCL but the interfacial hydration benefits of hydrogels. The electrospinning process results in partially aligned but interpenetrating fiber network with minimal internal phase separation, leading to anisotropic but strong mechanical properties even in the hydrated state; apparent ultimate tensile strengths of the swollen scaffolds ranged from 429 ± 39 kPa in the direction of fiber alignment (longitudinal) to 86 ± 25 kPa perpendicular to fiber alignment (cross-longitudinal), typical of PCL-based scaffolds and enabling efficient suture retention in different directions. However, contact angle measurements indicate hydrogel-like interfacial properties due to the presence of the interpenetrating POEGMA network. C2C12 myoblast proliferation in the PCL-POEGMA scaffolds was 50% higher than that observed on PCL-only scaffolds, a result attributed to the presence of the more hydrophilic POEGMA interpenetrating nanofiber network. Overall, this method is demonstrated to represent a facile single-step strategy to fabricate strong macroporous but still interfacially hydrophilic scaffolds for tissue engineering applications.

Ultrastable hierarchically porous nucleotide-based MOFs and their use for enzyme immobilization and catalysis

Immobilization of free enzymes facilitates their recovery and reuse, while also enhances their enzymatic characteristics. Hierarchically porous metal-organic frameworks (HP-MOFs) are promising candidates for enzyme immobilization. However, fabrication of HP-MOFs with more kinds of components as ligands is still a challenge. Herein, ultrastable crystalline MOFs with micro-, meso- and macroporous structure were constructed using guanosine 5′-monophosphate (GMP) as organic ligand through templated emulsification method. HP-MOFs crystals with the near rhomb-like, rod-like and slab-like morphology were interestingly obtained from Zn2+, Cu2+ and Cd2+ respectively. The HP-MOFs immobilized enzymes exhibited an enhanced enzymatic activity and stability. In addition, the immobilized CALB (Candida antarctica lipase B) showed great glycerolysis and esterification performances for glycerides preparation, with diacylglycerols (DAG) content over 60 wt% and triacylglycerols (TAG) content over 90 wt% obtained respectively from glycerolysis and esterification. Moreover, it retained 82.32 % of its initial glycerolysis activity after six cycles of reuse in glycerolysis. The present study will provide clues and show new horizons to explore new organic ligands for HP-MOFs fabrication, as well as to expand the applications of HP-MOFs and their supported enzymes.

Hierarchically Ordered Pore Engineering of Carbon Supports with High-Density Edge-Type Single-Atom Sites to Boost Electrochemical CO2 Reduction.

Metal sites at the edge of the carbon matrix possess unique geometric and electronic structures, exhibiting higher intrinsic activity than in-plane sites. However, creating single-atom catalysts with high-density edge sites remains challenging. Herein, the hierarchically ordered pore engineering of metal-organic framework-based materials to construct high-density edge-type single-atomic Ni sites for electrochemical CO2 reduction reaction (CO2RR) is reported. The created ordered macroporous structure can expose enriched edges, further increased by hollowing the pore walls, which overcomes the low edge percentage in the traditional microporous substrates. The prepared single-atomic Ni sites on the ordered macroporous carbon with ultra-thin hollow walls (Ni/H-OMC) exhibit Faraday efficiencies of CO above 90% in an ultra-wide potential window of 600mV and a turnover frequency of 3.4×104h-1, much superior than that of the microporous material with dominant plane-type sites. Theory calculations reveal that NiN4 sites at the edges have a significantly disrupted charge distribution, forming electron-rich Ni centers with enhanced adsorption ability with *COOH, thereby boosting CO2RR efficiency. Furthermore, a Zn-CO2 battery using the Ni/H-OMC cathode shows an unprecedentedly high power density of 15.9mW cm-2 and maintains an exceptionally stable charge-discharge performance over 100h.

Hierarchical porous MXene film with diffusion path optimization for supercapacitor

MXenes have immense potential in electrochemical energy storage owing to their outstanding physicochemical properties such as their oxygen-containing groups that impart additional pseudocapacitance to acidic electrolytes. However, during electrode assembly, MXene nanosheets undergo restacking because of hydrogen bonding and van der Waals forces, which causes electrolyte ions to traverse long diffusion pathways between the long and narrow nanosheets. Exploiting the oxidative properties of Ti3C2Tx, a hierarchical porous MXene film with micro-, meso- and macroporous structures was successfully prepared using a simple hydrothermal oxidation and etching process to create micro- and mesoporous structures, followed by ice templating to prepare three-dimensional (3D) linked macroporous structures. Because these hierarchical pores have synergistic effects on electrochemical activity and electrolyte ion diffusion, the film attained a specific capacitance of 539F/g at a current density of 2 A/g when it was used as a supercapacitor electrode, which corresponds to one of the highest values reported for MXene-based electrodes. The film retained 83% of its specific capacitance when the current density was increased to 40 A/g, and exhibited excellent cycling stability. By using this multi-porous MXene design, synergistic improvement in ion diffusion was successfully realized and thus a new strategy to prepare high-performance supercapacitor electrode materials was developed.

Toward Predicting the Formation of Integral-Asymmetric, Isoporous Diblock Copolymer Membranes.

The self-assembly and nonsolvent-induced phase separation (SNIPS) process of block copolymers and solvents enables the fabrication of integral-asymmetric, isoporous membranes. An isoporous top layer is formed by evaporation-induced self-assembly (EISA) and imparts selectivity for ultrafiltration of functional macromolecules or water purification. This selective layer issupported by a macroporous bottom structure that is formed by nonsolvent-induced phase separation (NIPS) providing mechanical stability. Thereby the permeability/selectivity tradeoff is optimized. The SNIPS fabrication involves various physical phenomena-e.g.,evaporation, self-assembly, macrophase separation, vitrification - and multiple structural, thermodynamic, kinetic, and process parameters. Optimizing membrane properties and rationally designing fabrication processes is a challenge which particle simulation can significantly contribute to. Using large-scale particle simulations, it is observed that 1) a small incompatibility between matrix-forming block of the copolymer and nonsolvent, 2) a glassy arrest that occurs at a smaller polymer concentration, or 3) a higher dynamical contrast between polymer and solvent results in a finer, spongy substructure, whereas the opposite parameter choice gives rise to larger macropores with an elongated shape. These observations are confirmed by comparison to experiments on polystyrene (PS)-block-poly(4-vinylpyridine) (P4VP) diblock copolymer membranes, varying the chemical nature of the coagulant or the temperature of coagulationbath.

Engineering dual-reinforced antibacterial and anti-fouling ultrafiltration membrane by in-situ synthesising super-dispersion and high-activity silver nanoparticles (AgNPs)

Membrane fouling, especially biofouling, would result in frequent cleaning and shorten membrane lifespan. Fabricating Ag nanoparticle (AgNP)-modified ultrafiltration (UF) membranes provided an innovative solution for in-situ membrane biofouling control. Inspired by the tongue’s taste generation mechanism, this study adopted sodium citrate and AgNO3 to in-situ synthesize AgNP-modified UF (i-Ag-UF) membrane with the characteristics of ‘super-dispersion and high-activity’ AgNPs, enhancing the antimicrobial and anti-fouling properties. Compared to the control, a perpendicular and rich macroporous finger-type structure was engineered in the i-Ag-UF membrane, which contributed to a 59 % permeability improvement (421.7 L m-2h−1 bar−1), thereby improving filtration efficiency and reducing operational costs. This enhancement was attributed to the in-situ synthesis of small-sized, super-dispersed AgNPs, improving compatibility and stability with membrane matrix, and enhancing resistance to interlayer shear stress during phase inversion. Furthermore, the i-Ag-UF membrane surface exhibited the highest hydrophilicity and surface polarity, which formed a hydration layer and increased pollutant repulsion, thereby greatly enhancing its anti-fouling performance and achieving a higher flux recovery rate of 98.64 %. Such enhancement could significantly improve the economic benefits and sustainability of the UF process. The i-Ag-UF membrane demonstrated exceptionally high antibacterial efficiency (>99.99 %), attributed to the widely dispersed, high-activity AgNPs with numerous exposure points. In addition, the i-Ag-UF membrane, with only 2.5 wt% Ag release after 50 days owing to the entanglement between AgNPs and polymer chains. These findings provide new insights into the fabrication of highly antibacterial and anti-fouling dual-enhanced UF membranes.

Preparation of Hierarchical Porous Monoliths With High Surface Areas by a Solvent Knitting Strategy.

Hierarchical porous hypercrosslinked monoliths (PolyHIPE-HCP) with ultrahigh specific surface areas are prepared via a solvent knitting strategy. Compared to previous work, the solvent knitting strategy is carried out in a relatively low air-controlled atmosphere with gradient heating starting from low temperature while using DCM (Dichloromethane) as both a solvent and a cross-linker, allowing for a slow and controlled cross-linking process, thereby achieving a BET surface area ranging from 514 to 728m2g-1. Scanning electron microscopy (SEM) shows that the knitting process does not affect the presence of macroporous structure in the PolyHIPE. With the introduction of mesopores and micropores, these hierarchical porous monoliths exhibit significant potential for applications in gas adsorption and water treatment. Hence, a universal, simple and low-cost method to synthesize polymeric monoliths with hierarchically porous structure and higher surface area is proposed, which has fascinating prospects in industrialization.