Membrane Substrate Research Articles

Self-Supporting Electrode Fabricated by Flowing Synthesis for Efficient Hydrogen Evolution Reaction

In order to achieve a balance between a good hydrogen evolution reaction (HER) performance and a low amount of catalyst loading, Pt@Ti membrane self-supporting electrodes have been fabricated by flowing synthesis. The characterizations by X-ray diffraction (XRD), X-ray photoelectric spectroscopy (XPS), and transmission electron microscopy (TEM) demonstrate the successful loading of Pt nanoparticles into the pores of a porous Ti membrane substrate. The scanning electron microscope (SEM) results demonstrate that the sizes of the Pt nanoparticles immobilized in Ti membrane pores are mostly in the range of 10–40 nm, and the average size was about 26 nm. The ICP test proves that the amount of Pt loading was only 0.760 mg cm–2. A minimum overpotential of 35 mV and a minimum Tafel slope of 30 mV dec–1 can be achieved for a Pt@Ti membrane self-supporting electrode at a current density of 10 mA cm–2 with 0.5 M H2SO4 as the electrolyte. No decay of current density is observed after a 10 h continuous electrolytic test. Besides, good HER performances can also be obtained under alkaline conditions and neutral conditions for Pt@Ti membrane self-supporting electrodes fabricated by flowing synthesis.

Functional Ultrathin Separators Proactively Stabilizing Zinc Anodes for Zinc-Based Energy Storage.

Ultrathin separators are indispensable to high-energy-density zinc-ion batteries (ZIBs), but their easy failure caused by zinc dendrites poses a great challenge. Herein, 23µm-thick functional ultrathin separators (FUSs), realizing superb electrochemical stability of zinc anodes and outstanding long-term durability of ultrathin separators, are reported. In the FUSs, an ultrathin but mechanically strong nanoporous membrane substrate benefits fast and flux-homogenized Zn2+ transport, while a metal-organicframework(MOF)-derived C/Cu nanocomposite decoration layer provides rich low-barrier zinc nucleation sites, thereby synergistically stabilizing zinc anodes to inhibit zinc dendrites and dendrite-caused separator failure. Investigation of the zinc affinity of the MOF-derived C/Cu nanocomposites unravels the high zincophilicity of heteroatom-containing C/Cu interfaces. Zinc anodes coupled with the FUSs present superior electrochemical stability, whose operation lifetime exceeds 2000h at 1mA cm-2 and 600h at 10mA cm-2 , 40-50 times longer than that of the zinc anodes using glass-fiber separators. The reliability of the FUSs in ZIBs and zinc-ion hybrid supercapacitors is also validated. This work proposes a new strategy to stabilize zinc anodes and provides theoretical guidance in developing ultrathin separators for high-energy-density zinc-based energy storage.

Designing adsorptive membranes for removing protein-bound uremic toxins via π-π and cation-π interaction

Protein-bound uremic toxins (PBUTs) are recently thought to critically influence overall organ dysfunction, morbidity, and mortality of chronic kidney disease (CKD) patients. However, traditional hemodialysis and/or hemoperfusion processes fail to remove PBUTs efficiently due to their strong affinity with albumins. Herein, we fabricated a novel adsorptive membrane incorporating amine/polyphenol/bimetal ions complexation in the polysulfone membrane substrate, which has a higher affinity with hippuric acid, p-cresol sulfate, and indoxyl sulfonate. The complexation is a synergy of polyelectrolyte (polyethyleneimine-tannic acid) and metal-phenolic (tannic acid/metals) networks. The adsorption behavior of those three uremic toxins on the optimized adsorptive membrane was investigated by kinetic and adsorption isotherm studies. From X-ray photoelectron spectroscopy analysis assisted by Fourier transform infrared reflection spectrum, we attribute the high adsorption capacity to π-π and/or cation-π interaction with aromatic ring groups of uremic toxins. The adsorptive membrane could effectively remove albumin bounded uremic toxins and water-soluble urea through a continuous dialysis process. Besides, the membrane showed excellent hemocompatibility and minimized immune responses by suppressing complement activation. The above results showed the potential clinical application of adsorptive membranes.

Photoadsorption and reaction mechanism of periwinkle shell ash in the removal of hazardous dye

AbstractCombined adsorption and photocatalysis synergy was explored in this research because the porosity of activated carbon and hydroxyl radicals' generation are the main drivers of the adsorption and photodecomposition efficiency of dyes. In this study, periwinkle shell ash (PSA) activated at 800 °C was used for the adsorption of toxic crystal violet (CRV) dyes. The PSA was characterized by scanning electron microscope, Fourier transform infrared spectroscopy, thermogravimetric analysis, Brunauer–Emmett–Teller surface area analysis, and X-ray diffraction. Findings showed that CRV adsorption was dependent on the dosage, pH, contact time, and initial concentration. The adsorption capacity was 46.82 at pH (9) for CRV, dosage amount of 0.2 g/L, and an adsorbate concentration of 70 mg/L. Pseudo-second order gave a perfect fitting-chemisorption mechanism with values >0.98 (R2). Maximum photodegradation (93–98%) was achieved when the catalyst dosage increased to 0.75 g. Thermodynamics confirmed a spontaneous/exothermic process. The photocatalysis process confirmed that the combined process was effective and determined to be the rate-determining step by Langmuir–Hinshelwood. The study concluded that PSA was an efficient adsorbent, and TiO2 was a key factor in the reaction mechanism and recommended for potential synthesis of membrane substrates, high performance, efficiency, and cost reduction.

Comparison of blocking reagents for antibody microarray-based immunoassays on glass and paper membrane substrates.

Background noise due to nonspecific binding of biomolecules on the assay substrates is one of the most common challenges that limits the sensitivity of microarray-based immunoassays. Background signal intensity usually increases when complex biological fluids are used because they have a combination of molecules and vesicles that can adsorb onto substrate surfaces. Blocking strategies coupled with surface chemistries can reduce such nonspecific binding and improve assay sensitivity. In this paper, we conducted a systematic optimization of blocking strategies on a variety of commonly used substrates for protein measurement in complex biofluids. Four blocking strategies (BSA, non-fat milk, PEG, and a protein-free solution) coupled with four surface chemistries (3-glycidoxypropyltrimethoxysilane (GPS), poly-L-lysine (PLL), aminoalkylsilane (AAS), and nitrocellulose (NC)) were studied for their effect on background, microspot, and net signal intensities. We have also explored the effect that these blocking strategies have when proteins in complex samples (plasma, serum, cell culture media, and EV lysate) are measured. Irregular spot morphology could affect signal extraction using automated software. We found that the microspots with the best morphology were the ones printed on GPS glass surfaces for all immunoassays. On NC membrane, the protein-based blocking strategies yielded the highest net fluorescent intensity with the antigen contained in PBS, plasma, serum, and serum-free cell culture media. Differently, with EV lysate samples, Pierce™ protein-free blocker yielded the best net signal intensity on both GPS and NC surfaces. The choice of blocking strategies highly depends on the substrate. Moreover, the findings discovered in this study are not limited to microarray-based immunoassays but can provide insights for other assay formats.

Synthesis and characterization of positive volume phase transition hydrogel membrane prepared using a cellulose substrate

ABSTRACT Thermo-responsive hydrogels display swell-collapse behavior in response to changing temperature. While the hydrogels themselves have many applications such as environmental and chemical separations, the hydrogel can be incorporated within a membrane substrate to improve its mechanical properties and expand the opportunities for development and implementation. The present work describes synthesis of positive volume transition temperature responsive poly(acrylamide-co-acrylic acid) hydrogels on cellulose paper substrates. Effects of factors including co-monomer ratios, degree of crosslinking and mass loading are assessed for Series A random copolymer hydrogels in terms of permeability response. Examination of the membranes is then extended to investigate inter-penetrating networks (IPN) between acrylamide and acrylic acid homo-polymer hydrogels. Series B membranes explore the impact of nonpolar ligands on temperature response through addition of butyl methacrylate co-monomer. For both random copolymer and IPN hydrogel membranes, mass loading dominates permeability performance, though certain criteria must be met. Performance of the Series A membranes was found to be ideal when monomer ratio was 1:1 and there was a lower degree of crosslinking. Addition of butyl methacrylate did not appear to have a consistent impact on the membrane response, appearing to be tied to the degree of crosslinking for random copolymer hydrogel coatings.

Ammonia sensing properties of PPy nanostructures (urchins/flowers) towards low-cost and flexible gas sensors at room temperature

High-performance room-temperature gas sensors have tremendous potential in real-world applications like air quality control, food safety, and health monitoring. In this work, we report an eco-friendly and one-step route for the chemical synthesis of hierarchical polypyrrole (PPy) nanotubes assembled urchins and flower-like nanostructures via a template-assisted method and examine their morphology-dependent gas sensing characteristics. The ammonia sensor was mounted on low-cost and highly flexible polyvinylidene fluoride (PVDF) membrane substrate for the fabrication of flexible sensor. The polypyrrole urchins and flower-like nanostructures exhibited high surface area of 194.9 m2/g and 101.05 m2/g along with highly porous structure confirmed by BET and SEM characterization. The nanotubes assembled urchin-like structure of PPy exhibited great response, repeatability, and long-term durability to NH3 gas in the range of 1–200 ppm owing to their high porosity, excellent flexibility, and large surface area. In addition, the PPy urchins based sensor exhibited low response time (23 s) and very high response of 34.7% towards 100 ppm concentration of ammonia gas at room temperature. From the flexibility point of view, proposed flexible sensor showed high mechanical robustness under extreme bending conditions, i.e. 900 bending angle and 400 bending cycles by showing no considerable change in response even after these extreme bending conditions. The proposed flexible gas sensor remarkable performance to detect ammonia at room temperature indicates its tremendous potential for wearable electronics applications.

Preserved subsurface morphology in NIPS and VIPS laser-induced graphene membranes affects electrically-dependent microbial decontamination

Laser-induced graphene (LIG) is a graphitic material that can be easily formed by CO2-laser irradiation on a variety of carbon-based substrates, including porous polymeric membranes. LIG-membrane formation involves lasing the top surface of a polymeric membrane, and converts essential polymer separation structures to porous LIG foam. However, in previous studies, separation properties could be partly recovered by forming LIG polymer composite layers or by coating the polymeric membrane substrate with trimethylaluminum (TMA) or graphene oxide (GO) to avoid melting or damaging the membrane pore structure and the subsurface polymeric structures during the lasing process. Herein, by optimizing the laser settings and fabrication conditions, we made LIG directly on uncoated porous PES membranes, while preserving the subsurface polymer. The effects of lasing on membrane properties were studied by comparing porous polymeric PES membranes fabricated using the non-solvent induced phase separation (NIPS) or the vapor-induced phase separation (VIPS) method. Membrane fabrication conditions such as the polymer concentration of the casting solution and the exposure time to the non-solvent were varied, and the NIPS method resulted in membranes with a finger-like polymer substructure morphology while the VIPS method resulted in membranes with an asymmetric cellular morphology. LIG-membranes prepared on NIPS membranes resulted in large permeability changes, while LIG on VIPS membranes gave only very minor changes. The antimicrobial activity of these LIG-membranes as porous electrodes was dependent on applied voltage and solution contact time and 4–6 log removal of bacteria at 10 V was achieved. Understanding LIG formation on porous polymeric membranes will minimize processing steps and might lead to electrically conductive membranes with controlled separation properties.

Flexible, Low-Cost, and Room Temperature Ammonia Sensor Based on Polypyrrole and Functionalized MWCNT Nanocomposites in Extreme Bending Conditions

We report a flexible and room temperature ammonia sensor based on polypyrrole/functionalized multiwalled carbon nanotubes (Ppy/f-MWCNTs). This nanocomposite has been synthesized by the in-situ chemical oxidative polymerization method and finally loaded on a transparent poly(vinylidene fluoride) (PVDF) membrane substrate. The entire flexible sensor fabrication process was cost-effective and easy to operate, making it ideal for commercial production on a wide scale. The optimized Ppy/f-MWCNT-based flexible sensor demonstrates improved sensing characteristics (26.5% for 100 ppm) with a low response time of 16 s and high response toward ammonia compared with pristine Ppy. In addition, high repeatability and long-term stability were also observed over a concentration range of 5–200 ppm. It shows high response toward ammonia among various gaseous analytes. Furthermore, the flexible sensor was mechanically robust and could produce a high response value even in extreme bending conditions. The flexible Ppy/f-MWCNT-based flexible sensors offer potential applications in advanced wearable devices to detect ammonia in the ambient environment.

Electrospun Nanofibrous Composite Membranes for Separations

ConspectusElectrospinning is regarded as an efficient method for directly and continuously fabricating nanofibers. The electrospinning process is relatively simple and convenient to operate and can be used to prepare polymer nanofibers for almost all polymer solutions, melts, emulsions, and suspensions with sufficient viscosity. In addition, inorganic nanofibers can also be prepared via electrospinning by adding small amounts of polymers into the inorganic precursors, which are generally regarded as nonspinnable. The diameter of the electrospun nanofibers can be tuned from tens of nanometers to submicrons by changing the spinning parameters. The nonwoven fabric stacked with electrospun fibers is a porous material with interconnected submicron pores, providing a porosity above 80%. However, limited by the unstable rheological properties of the electrospinning fluid, it is difficult to obtain nanofibers stably and continuously with an average diameter of <100 nm, which narrows the separation applications of the electrospun nanofibrous membranes to only microfiltration, air filtration, or use as membrane substrates. Therefore, to fully take advantage of electrospun nanofibrous membranes in other separation applications, electrospun nanofibrous composite (ENC) membranes were developed to improve and optimize their selectivity, permeability, and other separation performances. The composite membranes not only have all the advantages of single-layered or single-component membranes, but also have more flexibility in the choice of functional components.In this account, we summarize the two combination strategies to design and fabricate ENC membranes. One is based on the component combination, in which functional components are homogeneously or heterogeneously mixed in the fiber matrix or modified on the nanofiber surface. The other one is termed as the interfacial combination, in which functional skin layers are fabricated on the top of the electrospun membranes via interfacial deposition or interfacial polymerization, to construct selective barriers. The specific preparation approaches in the two combination strategies are discussed systematically. Additionally, the structural characteristics and separation performances of ENC membranes fabricated via these approaches are also compared and analyzed to clarify their advantages and range of utilization. Subsequently, the six applications of ENC membranes we focus on are demonstrated, including adsorption, membrane distillation, oil/water emulsion separation, nanofiltration, hemodialysis, and pervaporation. To meet their different requirements for separations, our consideration about the choice of combination strategies, related preparation methods, and functional components are discussed based on typical research cases. In the end, we conclude this account with an overview of the challenges in industrial manufacturing, mechanical strength, and interfacial attachment of ENC membranes and prospect their future developments.

Thin‐Film Composite Membrane with a Hydrophobic Substrate for Robust Membrane Distillation

AbstractMembrane distillation (MD) is a promising thermal desalination technology, but its application is largely limited by membrane wetting. This study introduces a thin‐film composite (TFC) membrane comprising a polyamide (PA) surface layer, a polydopamine (PDA) interlayer, and a hydrophobic polyvinylidene fluoride (PVDF) membrane substrate for anti‐wetting MD operations. With a PDA reaction time of 1 h, a compact and hydrophilic PDA interlayer forms on the PVDF membrane substrate, facilitating the subsequent formation of the PA surface layer. With 2 cycles of interfacial polymerization process, a dense PA surface layer forms on the PDA interlayer, rendering a TFC membrane with robust wetting resistance. From diffusion experiments and breakthrough pressure measurements, the TFC membrane exhibits excellent wetting resistance because the dense PA surface layer can prevent the wetting contaminants from reaching the hydrophobic membrane substrate due to the combination of the size exclusion effect and capillary effect. The results from this study shed lights on a new approach for the fabrication of robust MD membranes for practical applications.

Gas permeation and selectivity of polysulfone/carbon non-woven fabric membranes with sponge and finger-like structures

This research aims to investigate the effect of supporting polysulfone (PSF) membranes with different pore structures (sponge “SP” and finger “FP”) by non-woven carbon fibers (CF) on their gas permeability and selectivity for different gas mixtures (H2/CO2, H2/N2, and H2/CH4) to avoid the lower mechanical strength of the commercial membranes. The thickness of the PSF layer was modified during the preparation process using a phase inversion approach. The impact of the support CF fabric and different pore structures on the mechanical, chemical, thermal, permeability, and selectivity characteristics of the fabricated membranes were examined. The results revealed a strong incorporation between PSF and the fabric, resulting in enhanced pores, increased porosity and higher roughness. The FP membrane’s structure was found to have a smaller pore size of 56 nm, higher porosity (73.6%), surface roughness (44 nm) and higher strength (15.7 MPa) but less thermal stability (−36%) compared to the SP structure. Moreover, the SP structure exhibited higher gas permeability, particularly for H2, with improvements of 32% for H2 and CO2, 25% for CH4, and 10% for N2. Furthermore, the PSF/CF membrane with SP structure exhibited higher selectively with 15.8%, 26.9%, and 14.4% improvements for H2/CO2, H2/N2, H2/CH4, respectively, compared to FP membranes. These results suggest that CF fabric has great potential as a membrane substrate and PSF/CF membranes with SP structures have high potential for use in the H2 gas separation process in harsh environments.

Ectopic RING activity at the ER membrane differentially impacts ERAD protein quality control pathways

Endoplasmic reticulum-associated degradation (ERAD) is a protein quality control pathway that ensures misfolded proteins are removed from the ER and destroyed. In ERAD, membrane and luminal substrates are ubiquitylated by ER-resident RING-type E3 ubiquitin ligases, retrotranslocated into the cytosol, and degraded by the proteasome. Overexpression of ERAD factors is frequently used in yeast and mammalian cells to study this process. Here we analyze the impact of ERAD E3 overexpression on substrate turnover in yeast, where there are three ERAD E3 complexes (Doa10, Hrd1, and Asi1-3). Elevated Doa10 or Hrd1 (but not Asi1) RING activity at the ER membrane resulting from protein overexpression inhibits the degradation of specific Doa10 substrates. The ERAD E2 ubiquitin-conjugating enzyme Ubc6 becomes limiting under these conditions, and UBC6 overexpression restores Ubc6-mediated ERAD. Using a subset of the dominant-negative mutants, which contain the Doa10 RING domain but lack the E2-binding region, we show that they induce degradation of membrane tail-anchored Ubc6 independently of endogenous Doa10 and the other ERAD E3 complexes. This remains true even if the cells lack the Dfm1 rhomboid pseudoprotease, which is also a proposed retrotranslocon. Hence, rogue RING activity at the ER membrane elicits a highly specific off-pathway defect in the Doa10 pathway, and the data point to an additional ERAD E3-independent retrotranslocation mechanism.

Passive and reversible area regulation of supported lipid bilayers in response to fluid flow

Biological and model membranes are frequently subjected to fluid shear stress. However, membrane mechanical responses to flow remain incompletely described. This is particularly true of membranes supported on a solid substrate, and the influences of membrane composition and substrate roughness on membrane flow responses remain poorly understood. Here, we combine microfluidics, fluorescence microscopy, and neutron reflectivity to explore how supported lipid bilayer patches respond to controlled shear stress. We demonstrate that lipid membranes undergo a significant, passive, and partially reversible increase in membrane area due to flow. We show that these fluctuations in membrane area can be constrained, but not prevented, by increasing substrate roughness. Similar flow-induced changes to membrane structure may contribute to the ability of living cells to sense and respond to flow.

Honeycomb-like ReS2/polydopamine/Ag plasmonic composite assembled membrane substrate for rapid surface-enhanced Raman scattering analysis of 6-benzylaminopurine and alternariol in food

Herein, rhenium disulfide/polydopamine/Ag(ReS2/PDA/Ag) plasmonic composites assembled surface-enhanced Raman scattering(SERS) membrane substrates were fabricated for rapid analysis of 6-benzylaminopurine(6-BAP) and alternariol(AOH). The ReS2/PDA/Ag composites including ReS2/PDA/AgNPs and ReS2/PDA/AgNPs@thioglycolic acid(ReS2/PDA/AgNPs@TGA) were prepared via surface modification strategy and assembling method. With PDA modification, the ReS2/PDA/AgNPs improved the affinity of substrate to 6-BAP. With further TGA modification, the ReS2/PDA/AgNPs@TGA advanced the affinity between substrate and AOH. ReS2/PDA/Ag composites were assembled to SERS membrane substrate, which integrated SERS enhancement, fast separation/adsorption, and detection all-in-one. The membrane substrates exhibited good stability with relative standard deviations less than 5.5% and 6.5% for one batch and different batches, respectively. SERS methods based on the membrane substrates were developed for analysis of 6-BAP and AOH with detection limit of 24.4 and 23.6 μg/L, respectively. The methods were applied for determination of 6-BAP in bean sprout with recoveries of 87.1%− 107.0% and RSDs of 2.5%− 6.6%, AOH in pear with recoveries of 86.0%− 102.0% and RSDs of 2.9%− 8.1%, respectively. The results were confirmed by chromatographic method with relative error less than 5.5%. The analytical process completed within 35 min shows great potential in rapid food safety analysis.

Refractive axicon for X-ray microscopy applications: design, optimization, and experiment.

In a full-field transmission X-ray microscopy (TXM) setup, a condenser X-ray optical element is used to illuminate the sample by condensing the X-ray beam delivered by the synchrotron storage ring. On-going and future upgrades of synchrotron facilities to diffraction-limited storage rings will pose new challenges to these TXM setups, such as much smaller X-ray beams on the condenser. Here, we demonstrate that a refractive axicon can be used as an X-ray beam shaper to match the ring-shaped aperture of the condenser. Aiming at more efficient use of the incoming X-ray intensity, we explore several axicon designs both analytically and with numerical simulations. The axicons were produced by two-photon polymerization 3D printing on thin silicon nitride membrane substrates. The first characterization of the axicon was carried out at the TOMCAT beamline of the Swiss Light Source (Switzerland).

Design Strategies for Forward Osmosis Membrane Substrates with Low Structural Parameters-A Review.

This article reviews the many innovative strategies that have been developed to specifically design the support layers of forward osmosis (FO) membranes. Forward osmosis (FO) is one of the most viable separation technologies to treat hypersaline wastewater, but its successful deployment requires the development of new membrane materials beyond existing desalination membranes. Specifically, designing the FO membrane support layers requires new engineering techniques to minimize the internal concentration polarization (ICP) effects encountered in cases of FO. In this paper, we have reviewed several such techniques developed by different research groups and summarized the membrane transport properties corresponding to each approach. An important transport parameter that helps to compare the various approaches is the so-called structural parameter (S-value); a low S-value typically corresponds to low ICP. Strategies such as electrospinning, solvent casting, and hollow fiber spinning, have been developed by prior researchers-all of them aimed at lowering this S-value. We also reviewed the quantitative methods described in the literature, to evaluate the separation properties of FO membranes. Lastly, we have highlighted some key research gaps, and provided suggestions for potential strategies that researchers could adopt to enable easy comparison of FO membranes.

Nature-inspired construction of poly (vinylidene fluoride) membranes through the coordination coating of tannic acid with copper ions for oil-in-water emulsions separation

Construction of the separation membranes with underwater super-oleophobic property proposes a promising pathway in the field of oily wastewater treatment, but it is still plagued with the bottlenecks of the time-consuming preparation and the unsatisfied stability of resultant membranes. Herein, the alkali induced hydroxylation and the nature-inspired construction through the coordination coating of copper ions with tannic acid (Cu2+/TA) were performed on the poly (vinylidene fluoride) (PVDF) membrane substrate prepared by the thermally induced phase separation (TIPS). The introduced hydroxyl groups resulted from the membrane hydroxylation is beneficial for the subsequent construction of the Cu2+/TA coordination coating layer. The excellent hydrophilicity and the specifically hierarchical roughness of the immobilized coating layer endow the modified membranes with the hydrophilic/underwater super-oleophobic property. The optimized membrane correspondingly showed the improved flux of around 2000 L m−2•h−1 accompanied with the oil rejection of above 97.0% in treating two simulated oil-in-water emulsions (toluene and n-hexane). Besides, the flux recovery ratio increased from 72.4% of the pristine membrane to 93.3% of the modified membrane after the BSA fouling and regeneration test, which is also indicative of the improved antifouling behavior as a result of the hydrophilic coordination coating. The membrane stability was further demonstrated by the results of the sandpaper abrasion-resisting test and the long-term (up to 6 months) air-exposure treatment. This work might provide a straightforward strategy for designing advanced membrane for the large-scale applications of oil/water separation.

3D ceramic structure fabrication by Stereolithography and physicochemical characterization

In this study, a methodology for 3D printing of Silica (SiO2) structures for potential gas separation applications (either as membranes or as substrates for selective layers deposition) utilizing Stereolithography (SLA) is presented. The porosity, morphology and crystallinity of the 3D printed samples structure were optimized by the parametric study of the calcination profile of the printed ceramic SiO2 resin; the printed material was calcined at 450, 600 and 1250 °C by different residence times at different temperature steps. The microstructure of the 3D printed samples was characterized with Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS). Structural characterization (crystallinity and average crystal size) was performed by X-Ray Diffraction (XRD). The porosity and the specific surface area of the 3D printed samples were determined through the Brunauer–Emmett–Teller (BET) technique, which revealed that the surface area was gradually increased by increasing final calcination temperature. Permeability tests with flat sheet printed samples were performed in a constant pressure (isobaric) gas permeation system to quantify pure gases’ (e.g., CO2, N2, O2, Ar) permeances. Permselectivities of binary gaseous mixtures were obtained for printed samples calcined under different temperature profiles. The outcomes open new opportunities in 3D printing of versatile ceramic structures which can be exploited either as substrates for gas separation ceramic membranes or as membrane contactors for gas–liquid applications.

Stable Discoidal Bicelles: Formulation, Characterization, and Functions.

Bicellar mixtures have been used as alignable membrane substrates under a magnetic field applicable for the structural characterization of membrane-associated proteins. Recently, it has shown that bicelles can serve as nanocarriers to effectively deliver hydrophobic therapeutic molecules to cancer cells with a three- to ten-fold enhancement compared to that of liposomes of achemically identical composition. In this chapter, detailed preparation protocol, common structural characterization methods, the structural stability, the cellular uptake and a few unique functionsof bicellar nanodiscs are discussed.