Fast Permeation Research Articles

Ultra-fast photothermal-responsive Fe-TCPP-based thin-film nanocomposite membranes for ON/OFF switchable nanofiltration

• Fe-TCPP nanofibers based TFN nanofiltration membranes were prepared via IP. • Fe-TCPP nanofibers enhanced the permeance by improving the membrane hydrophilicity. • High permeation and dyes rejection were achieved. • Fe-TCPP based TFN membrane’s permeance was enhanced by light-illumination. Metal organic frameworks (MOFs) based Nanofiltration (NF) membranes have promising advantages in the separation of dyes and salts to purify the industrial polluted water. Herein, we report the synthesis of porphyrinic, porous and ultra-fast photothermal sensitive iron tetrakis(4-carboxyphenyl)porphyrin) (Fe-TCPP) MOFs nanofibers and the corresponding thin film nanocomposite (TFN) membranes by facile interfacial polymerization (IP). The Fe-TCPP nanofibers based TFN membrane enhances the pure water permeance to 28.1 L·m −2 ·h −1 ·bar −1 ( i.e., 3.5-fold higher than thin film composite (TFC)) by providing continuous hydrophilic flow pathways to permeate. The Fe-TCPP nanofibers contribute to the surface of TFN membrane, resulting not only fast permeation, but also ultra-high rejection of dyes i.e., 97.2%, 98.3% and 99.1% for Indocyanine Green, Brilliant Blue-R and Direct Red-80, respectively. Additionally, the TFN membrane also demonstrates 23–43 % salts rejection. Due to the ultra-fast photothermal responsive nature of Fe-TCPP nanofibers (88.4 °C increased temperature in 2 sec photo exposure), the water permeation of TFN NF membrane increases 30 % with 0.5 min under visible light-irradiation. This photo-induced ON/OFF separation is switchable. The enhanced permeation, high dyes rejection and photo-modulated ON/OFF nano-separation opens a new avenue for TCPP-based MOFs in the water purification technologies.

Systematic investigation on the electrochemical performance of Cd-doped ZnO as electrode material for energy storage devices

Many researchers have focused on enhancing the performance of energy storage devices to satisfy the growing demand for energy worldwide. This paper is an attempt to tune the capacitive behavior of pristine ZnO through its Cd doping via the simple synthetic method. To examine their electrochemical behavior, samples of modified ZnO with three concentrations of the dopant (Cd) (3, 6, and 9 wt% Cd-doped ZnO) were prepared. The as-prepared products were characterized by spectral as well as analytical techniques. The 9 wt% Cd-doped ZnO electrode, featuring fast electrolyte permeation and rich electrochemically active sites, showed an excellent specific capacitance (Csp) of 627 Fg−1 at a current density of 1 Ag-1 and substantial cycling stability of 93.3% even after 5000 GCD cycles. The addition of dopants enhanced electrical conductivity due to effective charge transfer and electron transport. The unique nanorod-like structure was found to be responsible for the exceptional electrochemical properties of the samples. Until now, there were no reports on Cd-doped ZnO nanorods as electrode material for supercapacitors. This work provides a simple and cost-effective method for fabricating a 9 wt% Cd-doped ZnO electrode, which may open up new possibilities for efficient electrodes in next-generation supercapacitors.

Well-dispersed few-layered MoS2 connected with robust 3D conductive architecture for rapid capacitive deionization process and its specific ion selectivity

Capacitive deionization (CDI) has aroused significant concern for its application in treating low-concentration brackish water. However, some carbonaceous materials suffer from the limited salt adsorption capacity (SAC), sluggish adsorption kinetics, and inferior selectivity to particular ions. Hence, we develop the well-dispersed few-layered two-dimensional pseudocapacitive material MoS2 connected with a robust 3D conductive architecture constructed by carbon nanotubes (CNT) and carbon spheres (CS) (MoS2@CNT-CS). The enhanced dispersibility and expanded interlayer of MoS2 nanosheets provide sufficient faradic effective sites for ion storage and transfer, while the interlaced carbonaceous network affords improved hydrophilicity, convenient electron transport path, and low charge transfer resistance for fast charge transportation and permeation. Therefore, the asymmetric hybrid CDI cell (CNT-CS for anode and MoS2@CNT-CS for cathode) delivers a prominent SAC (25.35 mg g−1), fast SAR (3.9 mg g−1 min−1), enhanced desalination kinetics, and favorable cycling stability. In addition, the specific ion selectivity of MoS2@CNT-CS electrode was evaluated systematically in the equimolar multi-salt solutions, and a selectivity order of Ca2+ > Na+ > Mg2+ > K+ was obtained. The molecular dynamic (MD) calculation provides the lowest intercalation energy for Ca2+ (−2.55 eV), further confirming the strong interaction and preferable pseudocapacitive deionization of MoS2@CNT-CS electrode to Ca2+ over other cations.

Performance enhancement of subcooled flow boiling on graphene nanostructured surfaces with tunable wettability

Modifying the surface wettability at the solid-liquid interface can significantly improve flow boiling heat transfer. The graphene nanoplatelets (GNPs) and epoxy additives form nanocomposites coatings with tunable wettability (superhydrophilic, superhydrophobic and hydrophobic) via a thermal curing process. They are applied for enhancing the subcooled flow boiling heat transfer in a minichannel. By comparing with the uncoated surface, the superhydrophilic GNPs coating shows the highest boiling heat transfer coefficient with a maximum enhancement of 64.9 %. The nanocapillary-networks of the superhydrophilic GNPs coatings facilitate the fast water permeation effect and induce an effective filmwise boiling heat transfer. Moreover, the superhydrophilic GNPs coatings facilitate bubble detachment process and suppress the formation of dry spot during the boiling process. On the contrary, the hydrophobic and superhydrophobic GNPs coatings act as impervious blankets for the intercalation of water and deteriorate the flow boiling rates. The effects of the subcooled degree and the mass flux of the bulk flow on the performance enhancement are also investigated. This study aims to investigate the flow boiling enhancement attributed to the graphene functionalized coatings and provides interesting insights of the ultrafast water permeation mechanism of graphene into the subcooled flow boiling heat transfer.

Durable and super-hydrophilic/underwater super-oleophobic two-dimensional MXene composite lamellar membrane with photocatalytic self-cleaning property for efficient oil/water separation in harsh environments

Super-wetting membranes with outstanding permeation and anti-fouling performance are promising candidates for highly-efficient oily wastewater treatment. Herein, we designed a facile strategy to fabricate the super-hydrophilic/underwater super-oleophobic two-dimensional MXene-based composite membrane via vacuum-assisted self-assembly of two-dimensional MXene nanosheets on porous polyvinylidene fluoride (PVDF) substrate and in situ mineralization of photocatalyst β-FeOOH on the membrane surface. Benefiting from the inherent super-wettability and regulated lamellar structure (Short transport pathway and abundant nanochannels), the resultant MXene-based composite membrane displayed fast permeation flux (500.38–1022.7 L m−2 h−1) and favorable separation efficiency (99.32–99.72%) for a series of micro-scaled oil-in-water emulsions. Importantly, the excellent photo-induced self-cleaning capability and low oil-adhesion contributed to the high anti-fouling resistance, outstanding reusability, and durability of 2D MXene composite membrane. Moreover, the 2D MXene composite membrane exhibited superior chemical stability, which enabled it to maintain highly efficient oil/water separation performance in high-temperature, high salty, and strongly corrosive conditions. This work provides a feasible route to fabricate durable super-wetting 2D membranes with photo-Fenton self-cleaning capability for the oily wastewater treatment in harsh environments.

Structure and Fate of Nanoparticles Designed for the Nasal Delivery of Poorly Soluble Drugs

Nanoparticles are promising mediators to enable nasal systemic and brain delivery of active compounds. However, the possibility of reaching therapeutically relevant levels of exogenous molecules in the body is strongly reliant on the ability of the nanoparticles to overcome biological barriers. In this work, three paradigmatic nanoformulations vehiculating the poorly soluble model drug simvastatin were addressed: (i) hybrid lecithin/chitosan nanoparticles (LCNs), (ii) polymeric poly-ε-caprolactone nanocapsules stabilized with the nonionic surfactant polysorbate 80 (PCL_P80), and (iii) polymeric poly-ε-caprolactone nanocapsules stabilized with a polysaccharide-based surfactant, i.e., sodium caproyl hyaluronate (PCL_SCH). The three nanosystems were investigated for their physicochemical and structural properties and for their impact on the biopharmaceutical aspects critical for nasal and nose-to-brain delivery: biocompatibility, drug release, mucoadhesion, and permeation across the nasal mucosa. All three nanoformulations were highly reproducible, with small particle size (∼200 nm), narrow size distribution (polydispersity index (PI) < 0.2), and high drug encapsulation efficiency (>97%). Nanoparticle composition, surface charge, and internal structure (multilayered, core–shell or raspberry-like, as assessed by small-angle neutron scattering, SANS) were demonstrated to have an impact on both the drug-release profile and, strikingly, its behavior at the biological interface. The interaction with the mucus layer and the kinetics and extent of transport of the drug across the excised animal nasal epithelium were modulated by nanoparticle structure and surface. In fact, all of the produced nanoparticles improved simvastatin transport across the epithelial barrier of the nasal cavity as compared to a traditional formulation. Interestingly, however, the permeation enhancement was achieved via two distinct pathways: (a) enhanced mucoadhesion for hybrid LCN accompanied by fast mucosal permeation of the model drug, or (b) mucopenetration and an improved uptake and potential transport of whole PCL_P80 and PCL_SCH nanocapsules with delayed boost of permeation across the nasal mucosa. The correlation between nanoparticle structure and its biopharmaceutical properties appears to be a pivotal point for the development of novel platforms suitable for systemic and brain delivery of pharmaceutical compounds via intranasal administration.

Photocatalytic GO/M88A “interceptor plate” assembled nanofibrous membrane with photo-Fenton self-cleaning performance for oil/water emulsion separation

Developing the high-efficient and robust antifouling membranes for oily emulsions to achieve the purpose of prolonging the service life of the membrane shows great demand because of the restriction of hydration anti-fouling mechanism strategy to against pollution. Herein, a hydrophilic photo-Fenton-like catalyst – GO/Fe-MOF assembled stabilized polyacrylonitrile (SPAN) nanofibrous membrane with underwater superoleophobicity, robust mechanical strength and photo-Fenton self-cleaning performance was firstly designed and fabricated via ultrasonic assistance, mussel-inspired fixation and low temperature hydrothermal synthesis methods. In this work, benefiting by the regulable amounts of GO nanosheets on the SPAN@GO/M88A membrane surface, the obtained membrane possessed sub-micrometer skin layer, which guarantees the balance of fast permeation flux (920–7083 ± 47 L m−2 h−1) and separation efficiency (>99.2%) for diesel/water emulsion with small emulsified oils. Moreover, introduced hydrophilic Metal-organic frame nanoparticles (MIL-88A (Fe)) into modified membrane endowed underwater anti-oil-fouling and photo-Fenton catalytic degradation performance for organic contaminants. Meanwhile, the charged GO/M88A heterostructure can assist to achieve demulsification for separation of surfactant-stabilized emulsions by strong electrostatic force. More importantly, attached and irremovable contaminants on the membrane can be quickly removed by photo-Fenton self-cleaning method, and achieved over 96% of recovery flux recovery ratio, which effectively prolonged the service life of the membrane. We believe the newly designed SPAN@GO/M88A membrane with hydration antifouling and photo-Fenton self-cleaning properties can stimulate more studies on revivable separation membranes for multifunctional applications.

Assembly of Defect-Free Microgel Nanomembranes for CO2 Separation.

The development of robust and thin CO2 separation membranes that allow fast and selective permeation of CO2 will be crucial for rebalancing the global carbon cycle. Hydrogels are attractive membrane materials because of their tunable chemical properties and exceptionally high diffusion coefficients for solutes. However, their fragility prevents the fabrication of thin defect-free membranes suitable for gas separation. Here, we report the assembly of defect-free hydrogel nanomembranes for CO2 separation. Such membranes can be prepared by coating an aqueous suspension of colloidal hydrogel microparticles (microgels) onto a flat, rough, or micropatterned porous support as long as the pores are hydrophilic and the pore size is smaller than the diameter of the microgels. The deformability of the microgel particles enables the autonomous assembly of defect-free 30-50 nm-thick membrane layers from deformed ∼15 nm-thick discoidal particles. Microscopic analysis established that the penetration of water into the pores driven by capillary force assists the assembly of a defect-free dense hydrogel layer on the pores. Although the dried films did not show significant CO2 permeance even in the presence of amine groups, the permeance dramatically increased when the membranes are adequately hydrated to form a hydrogel. This result indicated the importance of free water in the membranes to achieve fast diffusion of bicarbonate ions. The hydrogel nanomembranes consisting of amine-containing microgel particles show selective CO2 permeation (850 GPU, αCO2/N2 = 25) against post-combustion gases. Acid-containing microgel membranes doped with amines show highly selective CO2 permeation against post-combustion gases (1010 GPU, αCO2/N2 = 216) and direct air capture (1270 GPU, αCO2/N2 = 2380). The membrane formation mechanism reported in this paper will provide insights into the self-assembly of soft matters. Furthermore, the versatile strategy of fabricating hydrogel nanomembranes by the autonomous assembly of deformable microgels will enable the large-scale manufacturing of high-performance separation membranes, allowing low-cost carbon capture from post-combustion gases and atmospheric air.

Alginate Hydrogel Assisted Controllable Interfacial Polymerization for High-Performance Nanofiltration Membranes.

The deepening crisis of freshwater resources has been driving the further development of new types of membrane-based desalination technologies represented by nanofiltration membranes. Solving the existing trade-off limitation on enhancing the water permeance and the rejection of salts is currently one of the most concerned research interests. Here, a facile and scalable approach is proposed to tune the interfacial polymerization by constructing a calcium alginate hydrogel layer on the porous substrates. The evenly coated thin hydrogel layer can not only store amine monomers like the aqueous phase but also suppress the diffusion of amine monomers inside, as well as provide a flat and stable interface to implement the interfacial polymerization. The resultant polyamide nanofilms have a relatively smooth morphology, negatively charged surface, and reduced thickness which facilitate a fast water permeation while maintaining rejection efficiency. As a result, the as-prepared composite membranes show improved water permeance (~30 Lm−2h−1bar−1) and comparable rejection of Na2SO4 (>97%) in practical applications. It is proved to be a feasible approach to manufacturing high-performance nanofiltration membranes with the assist of alginate hydrogel regulating interfacial polymerization.

A facile development of superhydrophobic and superoleophilic micro-textured functionalized mesh membrane for fast and efficient separation of oil from water

Oil-contaminated water has become a severe threat to the environment, human and aquatic life. The major contributor to oil pollution is the periodical oil spill incidents and the oily effluents released from the industry. For efficient separation and recovery of oil from contaminated water, selective wettable surfaces have received substantial attention. However, high cost, compromised efficiencies, and complex preparation methods are the significant challenges in developing selective wettable membranes. A scalable approach is adopted to develop a highly selective super-wettable/superhydrophobic mesh for oil/water separation. The surface chemistry of the mesh membrane was controlled by surface activation (SA) and chemical functionalization with 3-[2-(2-Aminoethylamino)ethylamino]propyl-trimethoxysilane (TAS) and palmitic acid. The SEM and FTIR analysis have revealed the successful functionalization with the TAS and PA. SSM's functionalized surface has appeared super-selective for oil with a water contact angle of 161°. The surface attached-detached analysis has shown that water drops have no affinity to the functionalized mesh. During oil/water separation, the surface has selectively separated the oil from water under the force of gravity with a separation efficiency of up to 98.7%. PA-TAS-SA-SSM has shown the fast permeation of oil during oil/water mixture separation with a flux of 29,161 ± 2169 L m−2 h−1. Due to high flux and excellent separation efficiencies, the developed mesh membrane can be effectively used for oil/water separation.

Selective Ion Permeation through Stabilized Metal–Phenolic Grafted Graphene Oxide Membranes

AbstractThe structural stability and high permeability of 2D materials‐based membranes are key research interests for separation membranes. However, the instability of their microstructures due to the aqueous‐induced swelling phenomenon affects their performance. It is highly desirable to explore anti‐swelling approaches able to mitigate this challenge as well as develop 2D lamellar membranes with ion selective capabilities beyond the limits based on size exclusion mechanism. Herein, graphene oxide (GO) laminate membranes covalently anchored and intercalated with metal‐phenolic networks display suppressed swelling durability and resist delamination in aqueous media. The resultant Fe@TA‐GO membrane with confined d‐spacing boasts high water fluxes of up to 15.0 L m−2 h−1 under osmotic pressure (2 m sucrose). Furthermore, the permeation tests reveal that the interaction between the metal ions and the immobilized cation–ligand molecules influences the ion permeances through the functionalized GO membranes conducing to fast ion permeation rates with ion diffusion permselectivity as well as effective selective separation of organic contaminants. These results will help advance the applications of GO membranes for challenging ion separations related to sustainable resource recovery and environmental remediation of organic dye and metal ion contaminated wastewaters.

Hollow Silica‐Based Porous Liquids Functionalized Mixed Matrix Membranes for CO2 Capture

AbstractPorous liquids (PLs) are a newly emerging type of porous materials with empty cavities and tailed functionalities, demonstrating great potential in gas capture. However, PLs used as fillers of mixed matrix membranes (MMMs) are seldom reported till now. Herein, MMMs for CO2 selective separation were prepared by incorporating hollow silica PLs into Pebax‐1657 matrix. As expected, the liquid‐like property of PLs renders excellent filler dispersion. Besides, the hollow cavities construct fast permeation diffusion channels, reducing trans‐membrane permeation resistance. More importantly, CO2‐philic moieties of PLs lead to superior CO2 selective permeation. Therefore, the as‐prepared MMM exhibited a CO2 permeability up to 229.5 Barrer with a CO2/N2 selectivity up to 71.7 (241.9 % and 90.2 % increment than those of pure Pebex‐1657 membrane, respectively), surpassing the 2008 Robeson upper bound. Finally, molecular simulation was applied to verify the improved interaction between gas molecules and membrane by analyzing interaction parameters. Our work underlines the feasibility and importance of porous liquids to design advanced fillers in MMMs, which makes great promise for CO2 capture.

Electrophoretic nuclei assembly of MOFs in polyamide membranes for enhanced nanofiltration

Thin film nanocomposite (TFN) polyamide (PA) membranes has drawn increasing attention due to the improved physicochemical properties of the top layer for versatile separation performance. However, the commonly used fabrication approach, lacking a controllable loading of nanofillers, leads to a random and insufficient distribution of nanofillers into the PA layer and generates interfacial defects that deteriorate the membrane performance. Herein, a rational strategy for incorporating metal-organic frameworks (i.e., ZIF-8) into the PA layer via electrophoretic deposition (EPD) was proposed. Driven by an external direct current field, the ZIF-8 nanoparticles were uniformly assembled onto a porous ultrafiltration (UF) substrate for fabrication of high-performance TFN nanofiltration membranes by vacuum-assisted interfacial polymerization (IP). The resultant TFN nanofiltration membrane yielded an enhanced water permeability of 22.4 ± 1.2 L·m−2·h−1·bar−1, due to incorporation of ZIF-8 nanoparticles which created extra nano-channels for fast water permeation. Additionally, such an EPD process effectively tailored the membrane surface properties (e.g., zeta potential) and conferred a considerably high rejection for Na2SO4 (96.9 ± 0.7%) but a low rejection for NaCl (18.9 ± 2.5%), demonstrating an excellent selectivity between SO42− and Cl− ions. This study highlights the impressive efficacy of the EPD process in precisely anchoring nanomaterials to design high-performance TFN nanofiltration membranes for target separations.

Exclusive and fast water channels in zwitterionic graphene oxide membrane for efficient water–ethanol separation

AbstractGraphene oxide (GO) membranes have shown great prospects as the next‐generation membranes to tackle many challenging separation issues. However, the employment of GO membranes remains difficult for the precise separation of molecules with strong coupling effect and small size discrepancy such as water–ethanol. Herein, a new strategy of constructing exclusive and fast water channels in GO membrane was proposed to achieve high‐performance water–ethanol separation via the synergy between zwitterion‐functionalized GO and hydrophilic polyelectrolyte. The as‐formed ordered and stable channels possess high‐density ionic hydrophilic groups, which benefit from inhibiting the strong coupling between water and ethanol, facilitating the fast permeation of water molecules while suppressing ethanol molecules. As a result, the ultrathin GO‐based membrane acquires exceptionally high separation performance with a flux of 3.23 kg/m2 h and water–ethanol separation factor of 2,248 when separating water–ethanol (10 wt%/90 wt%) mixture at 343 K. This work paves a feasible way to construct 2D channels for the high‐efficiency separation of strong‐coupling mixtures.

Graphene-mediated electrospray cooling for discrete heat sources in microslits

Efficient and targeted cooling of small discrete heat sources located in a confined gap, such as a microslit, is challenging. In this study, we demonstrate by using electrospray technique, the charged droplets can be effectively transported within a microslit – consisting of a top substrate and a bottom substrate – and subsequently deposited on the heated spots located within it; up to approximately 28% cooling enhancement can be obtained, and, increases to approximately 67% cooling enhancement when the surface of the heated electrode (representing a heated spot) is coated with graphene nanoplatelets (GNPs), which can be attributed to the fast water permeation. Specifically, two heated electrodes are located within the microslit – one on the top substrate (top electrode) and one on the bottom substrate (bottom electrode) – and induced convection within the microslit. We observe that majority of the charged droplets are dragged by the convection and deposited mostly on the top heated electrode, indicating that near the heated electrodes, drag force exerted on the charged droplets is significant. Interestingly, by applying the GNPs coating only on one heated electrode, for the positively charged droplets, we observe a reduction in the cooling enhancement when the top electrode is coated with GNPs. This can be attributed to the positively charged GNPs surface repels the positively charged droplets. On the other hand, for negatively charged droplets, we observe a reduction in cooling enhancement when the bottom electrode is coated with GNPs. This can be attributed to the positively charged GNPs surface attracts the negatively charged droplets. These findings are crucial for the design of an effective cooling system, particularly for the targeted cooling of small heat sources within microslit.

Photochemically Produced Superhydrophobic Silane@polystyrene‐Coated Polypropylene Fibrous Network for Oil/Water Separation

Cost-effective separation of oil and immiscible organic contaminants from water has become an urgent challenge to protect aquatic and human life from devastating effects. Therefore, it has become imperative to develop super-selective materials for efficiently separating oil from water. In this work, a superhydrophobic surface has been formed that consists of a silane@polystyrene-coated polypropylene fibrous network (silane@PS-PPF) for efficient separation of accidentally spilled oil from water. The superhydrophobic PPFs were designed by a simple, cost-effective two-step process that includes photochemically controlled polymerization of styrene and subsequent dip coating in octadecyltrichlorosilane solution. The hydrophobic surface (CA=129°±4°) of the PS coated PPF after treating with silane was turned into a superhydrophobic body (CA=161°±2°). The achieved silane@PS-PPF fibrous network selectively allowed the fast permeation of the oils and non-polar organic liquids by altogether rejecting water during operation. The separation efficiency for various oils from the contaminated water was 96 to 99%, with a high flux in the range of 7606±312 L m-2 h-1 to 9870±151 L m-2 h-1 . Apart from being used as a filter, the silane@PS-PPF was also used as an oil absorber and has shown an absorption capacity in the range of 1185 to 1535% for various oils. We anticipate that the developed silane@PS-PPF, due to its facile synthetic route, cost-effectiveness, and high performance, can be effectively used in oily wastewater treatment and clean-up of large oil spills from water.

Fast Permeation of Small Ions in Carbon Nanotubes.

Simulations and experiments have revealed enormous transport rates through carbon nanotube (CNT) channels when a pressure gradient drives fluid flow, but comparatively little attention has been given to concentration‐driven transport despite its importance in many fields. Here, membranes are fabricated with a known number of single‐walled CNTs as fluid transport pathways to precisely quantify the diffusive flow through CNTs. Contrary to early experimental studies that assumed bulk or hindered diffusion, measurements in this work indicate that the permeability of small ions through single‐walled CNT channels is more than an order of magnitude higher than through the bulk. This flow enhancement scales with the ion free energy of transfer from bulk solutions to a nanoconfined, lower‐dielectric environment. Reported results suggest that CNT membranes can unlock dialysis processes with unprecedented efficiency.

Saline Water Electrolysis Membranes Prepared via the Simultaneous Irradiation of Electron-Beam

Polymer electrolyte membrane water electrolysis is a representative electrochemical process to produce both hydrogen and oxygen gases by applying electricity. Perfluorinated sulfonic acid (PFSA) ionomers have been widely used as electrode binder materials owing to their high proton conductivity and excellent compatibility with membrane materials with identical or similar chemical architectures. Different in the membrane materials, PFSA binder materials should have fast gas permeation behavior to minimize mass flux resistance. It makes it difficult to use the same ionomer dispersion for both applications. In this study, the average size of dispersed PFSA ionomer particle was controlled via a supercritical technique. The relationship between ionomer dispersion characteristics and electrochemical performances was systematically investigated.

Effective Permeation of Anticancer Drugs into Glioblastoma Spheroids via Conjugation with a Sulfobetaine Copolymer.

Three-dimensional cell aggregates (spheroids) are becoming a research focus because their construction is similar to that in vivo microenvironments, enabling the acceleration of drug discovery and reducing the need for animal tests, and other advantages. However, the delivery of drugs to the inside of spheroids is time-consuming and has low efficiency. In this study, we selected a sulfobetaine copolymer that translocates to the cell membrane in monolayer cultured cells as a nanocarrier of anticancer drugs. Doxorubicin (Dox) and 17-demethoxy-17-allylamino geldanamycin (17AAG) were modified to the copolymer of sulfobetaine methacrylate and poly(ethylene glycol) methacrylate, P(SB-PEG), and added to glioblastoma A-172 cell spheroids. Dox-P(SB-PEG) showed fast permeation into A-172 spheroids, and the fluorescence in cells was observed in the center area of the spheroids within 1 h of polymer addition. Conversely, only the outer one to two cell layers of spheroids were observed when Dox was added to the spheroids. Dox-P(SB-PEG) in A-172 spheroids was localized in the mitochondria of each cell and exhibited comparable drug efficacy to that of Dox in growth inhibition assays of A-172 spheroids. Moreover, approximately 10-fold higher drug efficacy in growth inhibition and invasion of A-172 spheroids was found using 17AAG-P(SB-PEG). Conjugating anticancer drugs with P(SB-PEG) is a promising strategy to enhance drug permeation and efficacy against spheroid cells.

Enhanced Selective Hydrogen Permeation through Graphdiyne Membrane: A Theoretical Study.

Graphdiyne (GDY), with uniform pores and atomic thickness, is attracting widespread attention for application in H2 separation in recent years. However, the challenge lies in the rational design of GDYs for fast and selective H2 permeation. By MD and DFT calculations, several flexible GDYs were constructed to investigate the permeation properties of four pure gas (H2, N2, CO2, and CH4) and three equimolar binary mixtures (H2/N2, H2/CO2, and H2/CH4) in this study. When the pore size is smaller than 2.1 Å, the GDYs acted as an exceptional filter for H2 with an approximately infinite H2 selectivity. Beyond the size-sieving effect, in the separation process of binary mixtures, the blocking effect arising from the strong gas–membrane interaction was proven to greatly impede H2 permeation. After understanding the mechanism, the H2 permeance of the mixtures of H2/CO2 was further increased to 2.84 × 105 GPU by reducing the blocking effect with the addition of a tiny amount of surface charges, without sacrificing the selectivity. This theoretical study provides an additional atomic understanding of H2 permeation crossing GDYs, indicating that the GDY membrane could be a potential candidate for H2 purification.