Varying Pore Size Research Articles

Exploring Schwann Cell Behavior on Electrospun Polyhydroxybutyrate Scaffolds with Varied Pore Sizes and Fiber Thicknesses: Implications for Neural Tissue Engineering.

The placement of a polymeric electrospun scaffold is among the most promising strategies to improve nerve regeneration after critical neurotmesis. It is of great interest to investigate the effect of these structures on Schwann cells (SCs), as these cells lead nerve regeneration and functional recovery. The aim of this study was to assess SC viability and morphology when cultured on polyhydroxybutyrate (PHB) electrospun scaffolds with varied microfiber thicknesses and pore sizes. Six electrospun scaffolds were obtained using different PHB solutions and electrospinning parameters. All the scaffolds were morphologically characterized in terms of fiber thickness, pore size, and overall appearance by analyzing their SEM images. SCs seeded onto the scaffolds were analyzed in terms of viability and morphology throughout the culture period through MTT assay and SEM imaging. The SCs were cultured on three scaffolds with homogeneous smooth fibers (fiber thicknesses: 2.4 μm, 3.1 μm, and 4.3 μm; pore sizes: 16.7 μm, 22.4 μm, and 27.8 μm). SC infiltration and adhesion resulted in the formation of a three-dimensional network composed of intertwined fibers and cells. The SCs attached to the scaffolds maintained their characteristic shape and size throughout the culture period. Bigger pores and thicker fibers resulted in higher SC viability.

Modification of nanofiltration membranes using beta-cyclodextrin derivatives with different functional groups for enhanced removal of organic micropollutants

Simultaneous enhancement in the removal of organic micropollutants (OMPs) and water permeance is highly desirable for nanofiltration (NF)-based drinking water treatment. This study employed two cyclodextrin derivatives with different functional groups, i.e., (2-hydroxypropyl)-β-cyclodextrin (HP-β-CD) and sulfobutylether-β-cyclodextrin (SBECD), as aqueous additives for polyamide (PA) membrane fabrication. Characterization results revealed that HP-β-CD tended to enrich piperazine (PIP) monomers through hydrogen bonding, resulting in a thin but dense PA layer. Conversely, SBECD moderated PIP diffusion through electrostatic forces and steric hindrance, participated more in the interfacial polymerization reaction and yielded an active layer with a coexistence of polyester and polyamide. Both the CD derivative modified membranes exhibited improved surface hydrophilicity, enhanced roughness, and reduced active layer thickness, leading to over 60 % water permeance improvement without the obvious variation of pore size. This enabled the optimal membranes, especially the HP-β-CD incorporated one, highly advantageous in overcoming the trade-off effect between water permeance and OMP rejection. Meanwhile, the strongly negatively charged SBECD modified membrane showed reduced rejections for divalent cations, making it more resistant to scaling. This study offers an efficient approach to tailoring membrane water/solute selectivity and solute/solute selectivity, which has great potential in NF membrane development for drinking water treatment.

Manufacturing Method and Thermal Properties of Open-Cell Type Aluminum Foam by Replication Casting Process

Open-cell type aluminum foam possesses unique structural characteristics comprising numerous interconnected pores within. This intriguing structure facilitates the passage of fluids (gas or liquid) through the interior of the open-cell type aluminum foams, enabling easy transfer to the exterior. The objective of this study is to manufacture open-cell type aluminum foams with varying pore sizes using the replication casting process and to evaluate their thermal properties. The equipment designed for the production of open-cell type aluminum foams consists of a chamber and an inner container. The chamber is connected to a vacuum line and an Ar gas line, with the container positioned inside. The aluminum alloys utilized for the foams were A356 and ADC12, and Na2CO3 served as the space holder. As a result of manufacturing the foams, there was no significant difference of porosity with space holder size and alloy types, the porosity averaged around 62%. To investigate the thermal properties of open-cell type aluminum foams in relation to pore size and alloy types, temperature variations were measured during sample heating via the hot plate method. Consequently, it was confirmed that the thermal properties of the foams were influenced by the structural conditions and alloy types.

Precise and ultra-wide molecular sieving capability with size-dependent COF layers for fast organic solvent nanofiltration

Four covalent organic framework (COF) layers with different alkyl side chains are used to create thin film composite (TFC) membranes via the improved unidirectional diffusion synthetic (UDS) technique. The synthesized membranes consist of polyacrylonitrile (PAN) substrates and TAPB-TPOCx COF (x = 1, 4, 6, and 8) layers, whose pore size and pore environment are tuned by direct integration of variable-length of TPOCx monomers. For organic solvent nanofiltration (OSN), we apply these COF membranes with variable thickness and pore size to test for the sieving ability of various organic pollutant surrogates. With the COF layers' bi-variable thickness and substituent length, the range cut-off molecular weight (330–970 g mol−1) for TAPB-TPOCx COF membranes involves the vast majority of OSN molecular sieving ranges. The COF membranes demonstrate precise molecular sieving capability with higher permeance of polar and nonpolar organic solvents than the state-of-the-art polymeric membranes.

Geo-storage of hydrogen in organic-rich shales: Multicomponent selectivity of organic nanopores

The gas adsorption capacity of kerogen is commonly obtained through experimental isothermal adsorption procedures. These experiments employ mathematical models called adsorption isotherms, which bridge the gap between empirical data and theoretical frameworks to offer a continuous representation of the underlying processes in the depleted shale formation with some fraction of resident adsorbed natural gas. However, an exploration of the adsorption behavior of H2, in the presence of CH4, C2H6, C3H8, and CO2 in organic-rich porous media of varying pore size remains an unaddressed area of study. Considering this, in this study, we conduct a molecular simulation of the adsorption and diffusion behavior of hydrogen (H2), methane (CH4), ethane (C2H6), propane (C3H8), and carbon dioxide (CO2) within a representative kerogen organic nanopore structure. In particular, we studied hydrogen adsorption behavior in organic-rich shale formations in varying nanopore size and multi-gas components. We also evaluate the suitability of different adsorption models (Langmuir, Langmuir-Freundlich, Toth) for depicting the adsorption characteristics of single species. For the multicomponent mixture (H2/CO2/CH4/C2H6/C3H8), we apply Langmuir ratio correlation model (LRC). The findings indicate C3H8 demonstrates the highest adsorption potential, while CH4 ranks lowest, followed by H2, CO2 and C2H6 exhibit intermediate potential. Furthermore, the adsorption of each species is hindered by organic nanopores of 1 nm, as opposed to 2 nm nanopores. For multicomponent adsorption, hydrogen exhibits minimal presence at equilibrium, which can be attributed to its higher diffusivity compared to other gases. Notably, the Langmuir, Toth, and Langmuir-Freundlich models exhibit ability to accurately depict the overall adsorption trends single-component. However, for the multicomponent mixture (H2/CO2/CH4/C2H6/C3H8), the LRC is found reasonable effective to capture the adsorption.

Effect of high-temperature drying at different moisture levels on texture of dried noodles: Insights into gluten aggregation and pore distribution

In this study, the impacts of high-temperature drying (80 °C) at varying moisture levels HT1 (30%) and HT2 (12%) on texture of dried noodles were investigated by considering the protein aggregation and pore distribution in both dried and cooked noodles. In comparison to medium-temperature drying (45 °C), an increase in protein aggregation was observed in dried noodles obtained under HT1. Additionally, HT1 conditions led to uneven gluten network and significant variations in pore size, which ultimately reduced the bending resistance of dried noodles from 9.45% to 31.82%. Upon cooking, the protein in noodles from HT1 underwent slight depolymerization, resulting in lower protein aggregation as compared to noodles from HT2, which negatively affected the edible quality of products from HT1. Our findings demonstrated that dried noodle qualities under HT2 increased up to 32.73% compared to medium-temperature drying and HT1, due to suitable protein aggregation and smaller pore distribution associated with HT2. Finally, the degree of protein aggregation in cooked noodles is a more accurate quality indicator than analyzing dried noodles.

Analyzing Pore Evolution Characteristics in Cementitious Materials Using a Plane Distribution Model

This research aims to analyze the distribution and evolution of pores within the planar structure of cement-based materials. Utilizing digital imaging methods, a model for pore plane distribution was established, and the evolutionary patterns of both total pore numbers and varying pore sizes in cement-based materials were investigated. The research introduced an innovative experimental method for analyzing pore distribution within cement-based planar structures. Additionally, a hybrid method was proposed, combining automated image binarization thresholding with manual comparative analysis, thereby enhancing the feasibility of comparative research. Pores were categorized into four distinct sizes: tiny pores (5–200 μm), small pores (200–500 μm), medium pores (500–1000 μm), and large pores (>1000 μm). Areas with apertures <5 μm were classified as dense areas. The findings indicated that the overall number of pores in cement-based materials increased due to the influence of styrene butadiene latex additives. However, at a 15% dosage, the rate of pore formation reached an inflection point, confirming that various factors, such as styrene butadiene latex, air bubbles, and the cement-based material itself, collectively influenced pore formation. The research also demonstrated that styrene butadiene latex affected the four categorized pore sizes differently. Importantly, a higher latex dosage did not necessarily lead to a proportional increase in pore content. Pore content was influenced by multiple factors and exhibited different distribution patterns. The number of micropores, although relatively small, gradually increased with higher latex dosages, while small and medium pores generally showed an upward trend. At a 10% latex dosage, both small and medium pores reached a turning point in their rate of increase. Large pores also exhibited a general increase, peaking at a latex dosage of 10%. It was confirmed that both the total pore volume and the content of micropores were critical factors in determining the mechanical properties of cementitious materials. Higher porosity and micropore content generally weakened mechanical performance. However, at a small latex dosage, there was an improvement in flexural strength. When the latex dosage reached 15%, the total pore and micropore content declined, resulting in a balanced increase in flexural strength and a mitigated decline in compressive strength. This study offers valuable insights into the evolution of total pore volume and the content of pores of various sizes, providing a theoretical basis for the meticulous selection of additive types and dosages from a microscopic perspective.

Morphology and Crystallinity Effects of Nanochanneled Niobium Oxide Electrodes for Na-Ion Batteries.

Niobium pentoxide (Nb2O5) is a promising negative electrode for sodium ion batteries (SIBs). By engineering the morphology and crystallinity of nanochanneled niobium oxides (NCNOs), the kinetic behavior and charge storage mechanism of Nb2O5 electrodes were investigated. Amorphous and crystalline NCNO samples were made by modulating anodization conditions (20-40 V and 140-180 °C) to synthesize nanostructures of varying pore sizes and wall thicknesses with identical chemical composition. The electrochemical energy storage properties of the NCNOs were studied, with the amorphous samples showing better overall rate performance than the crystalline samples. The enhanced rate performance of the amorphous samples is attributed to the higher capacitive contributions and Na-ion diffusivity analyzed from cyclic voltammetry (CV) and the galvanostatic intermittent titration technique (GITT). It was found that the amorphous samples with smaller wall thicknesses facilitated improved kinetics. Among samples with similar pore size and wall thickness, the difference in their power performance stems from the crystallinity effect, which plays a more significant role in the resulting kinetics of the materials for Na-ion batteries.

Modeling the Drying Process of Porous Catalysts: Impact of the Pore Size Distribution.

The distribution of catalytically active species in heterogeneous porous catalysts strongly influences their performance and durability in industrial reactors. A drying model for investigating this redistribution was developed and implemented using the finite volume method. This model embeds an analytical approach regarding the permeability and capillary pressure from arbitrary pore size distributions. Subsequently, a set of varying pore size distributions are investigated, and their impact on the species redistribution during drying is quantified. It was found that small amounts of large pores speed up the drying process and reduce internal pressure build up significantly while having a negligible impact on the final distribution of the catalytically active species. By further increasing the amount of large pores, the accumulation of species at the drying surface is facilitated.

Analysis of the influence of different pore ratios on methane adsorption characteristics of coal

The diverse pore structures in coal are pivotal in coalbed methane storage and transportation, making it highly significant to explore methane adsorption characteristics across varying pore sizes for effective prevention and control of coal mine gas disasters. Using the proposed graphene nanotube filling method, eight coal molecule models with varying pore size ratios were constructed, including four different pore radii: 0.35 nm, 0.55 nm, 0.75 nm, and 2 nm. Methane adsorption amount, methane density, and methane concentration distribution were obtained through Monte Carlo (GCMC) and molecular dynamics (MD) simulation methods. The research results show that coal consisting of multiple pore sizes had a better methane adsorption capacity than a single pore size. Combining pore sizes of 0.35 nm, 0.55 nm, and 0.75 nm in a 1:2:1 ratio resulted in the highest excess methane adsorption capacity in coal, reaching 5.623 mmol/g. The single pore size of 0.55 nm in coal had the lowest excess adsorption amount of methane, which was 2.236 mmol/g. The presence of mesopores weakened the methane adsorption capacity of coal, and this weakening effect increased with the increase of mesopore proportion. In the model composed of single pore size micropores, the methane concentration inside the pores was uniformly distributed. The coexistence of multiple micropores may lead to methane filling in the micropores in a monolayer adsorption form. The coexistence of micropores and mesopores does not alter methane filling in the micropores and monolayer adsorption in the mesopores. The research results provide new insights into our understanding of the impact of pores on methane adsorption in coal.

Prediction model of compressive strength of foamed concrete considering pore size distribution

To more accurately evaluate the relationship between pores and compressive strength of foamed concrete, the effects of density, water-cement ratio, and foaming agent type on porosity, pore size distribution, and compressive strength were studied. It was found that as the density decreased and the water-cement ratio increased, the number of larger-sized pores increased and the pore size distribution became wider and more non-uniform. Further, the pore structure of lower-density foamed concrete was more susceptible to the influence of density and water-cement ratio more likely to produce larger size pores. Particularly, foaming agent type had a significant effect on the pore size distribution. The pore size variation of foamed concrete was primarily attributed to the initial size of fresh foam and the complex merging and escape phenomena occurring in the foam in the slurry, the process of preparation and forming. It was also found that smaller porosity and more concentrated and uniform pore size distribution were more beneficial for strength. Additionally, to quantify the combined effect of porosity and pore size distribution on compressive strength, this paper innovatively proposes the parameters of the “pore synthesis impact factor”. Finally, a new empirical model relating the porosity, size distribution, and compressive strength is presented.

Melt Electrowriting of Nylon-12 Microfibers with an Open-Source 3D Printer.

This study demonstrates how either a heated flat or cylindrical collector enables defect-free melt electrowriting (MEW) of complex geometries from high melting temperature polymers. The open-source "MEWron" printer uses nylon-12 filament and combined with a heated flat or cylindrical collector, produces well-defined fibers with diameters ranging from 33±4 to 95±3µm. Processing parameters for stable jet formation and minimal defects based on COMSOL thermal modeling for hardware design are optimized. The balance of processing temperature and collector temperature is achieved to achieve auxetic patterns, while showing that annealing nylon-12 tubes significantly alters their mechanical properties. The samples exhibit varied pore sizes and wall thicknesses influenced by jet dynamics and fiber bridging. Tensile testing shows nylon-12 tubes are notably stronger than poly(ε-caprolactone) ones and while annealing has limited impact on tensile strength, yield, and elastic modulus, it dramatically reduces elongation. The equipment described and material used broadens MEW applications for high melting point polymers and highlights the importance of cooling dynamics for reproducible samples.

Production of higher hydrocarbon-pool from bio-ethanol for fuel applications

In a way to explore the inherent acidity and porosity properties of zeolites for the conversion of renewable biomass-derived ethanol into various fuel stocks, three types of zeolites; HZ, HY, and HB have been studied in their proton form. The studies indicated the formation of catalyst-dependent hydrocarbon composition of the product falling in gasoline and jet fuel for the specific end-use applications. The flexibility in product choice facilitated by changing the catalyst makes the present process suitable for industrial applications based on the nature of product in demand. At optimized temperature and pressure reaction conditions, HB zeolite produced >40 wt% jet fuel hydrocarbons (T = 400 °C and P = 50 bar), HZ produced 53 wt% octane gasoline (RON >100) and HY zeolite produced 25 wt% of olefins in liquid product. The novelty of the present process lies in its simple, single-step, continuous-flow vapour-phase single catalytic process operating on zeolites bearing no metal function but possessing variable pore size and other catalytic properties required for producing higher range hydrocarbons from ethanol.

Design criteria for selective nanofluidic ion-exchange membranes

Polymeric ion-exchange membranes (IEMs) are key to many electrochemical processes, but their intrinsic selectivity limitations restrict scale-up possibilities. Nanofluidic IEMs, based on inorganic rigid materials and charged nanopores, offer a promising alternative. We present design criteria for selective nanofluidic membranes. We used commercial anodized aluminium oxide (AAO) membranes with varying pore sizes to measure permselectivity between different KCl concentrations. Our experiments reveal that membranes with 10-nm pores have permselectivities above 90%, comparable to those of polymeric IEMs, up to electrolyte concentrations of 0.15 vs. 0.75 M. To our knowledge, this is the highest reported ion selectivity for nanofluidic IEMs. Conversely, asymmetric AAO membranes featuring a thin selective layer, exhibited low permselectivity. We explored the influence of other parameters through simulations using the space-charge model. Our numerical results indicate that pore size and surface potential are the most sensitive parameters for increasing selectivity. Additionally, pore length has a minimum requirement for good performance although increasing it beyond the μm scale yields no significant result. This study highlights nanofluidic IEMs as a promising alternative to polymeric IEMs and their capability to improve performance of many electrochemical processes, especially those involving low electrolyte concentrations on at least one membrane side.

Synthesis of mesoporous carbon particles with different pore sizes by soft template method

The Stöber method provides a facile procedure for making carbon spheres with controlled particle sizes and is considered to be low-cost. In this study, a facile method has been established for synthesizing porous carbon spheres with variable pore sizes using a modified Stöber process. The influence of acid treatment and manipulating the carbonization process heating rate on the pore size and morphology of the particles was investigated by nitrogen adsorption, Scanning Electron Microscopy (SEM), Powder X-ray diffraction (XRD), Raman and Fourier Transform Infrared Spectroscopy (FTIR). According to the results, carbon spheres were in the size range between 1 and 7 microns. Pore size characterization shows that the pore diameter has increased by increasing the heating rate as well as by performing acid treatment. Tunable pore sizes from 2.25 to 8 nm have been evidenced by the experiments. These synthesized mesoporous carbons with different pore sizes which facilitate penetration of molecules and ions are promising as effective materials for adsorption, encapsulation and material delivery applications.

Recent developments in the application of covalent organic frameworks in capillary electrochromatography

Capillary electrochromatography (CEC) has received increased attention from the academic community because it combines the excellent selectivity of high performance liquid chromatography (HPLC) and the high efficiency of capillary electrophoresis (CE). Selecting the most appropriate stationary phase material is crucial to achieve better separation effects in CEC. In recent years, a considerable number of materials, such as graphene oxide, proteins, metal organic frameworks, and covalent organic frameworks (COFs), have been widely used as stationary phases in CEC to further improve its separation performance and extend its scope of potential applications. Among these materials, COFs have shown great application prospects in CEC owing to their unique properties, which include high porosity, large surface area, excellent stability, tunable pore size, and high designability of the framework structure. This review systematically summarizes published papers on the development and application of COFs in CEC from 2016 to 2023. First, two COF-based capillary columns (i. e., open-tube CEC columns and monolithic CEC columns) and their preparation methods are introduced. Second, the applications of CEC based on COF stationary phases in the separation of environmental endocrine disruptors, pesticides, aromatic compounds, amino acids, and drugs, particularly chiral drugs, are systematically summarized. The separation mechanism of CEC based on COF stationary phases is also introduced. At present, the good separation ability of COF-based CEC is mainly attributed to two factors: 1) The size exclusion effect of the pores of the COF stationary phase. Because of differences in the sizes of their organic molecular building units and side chains, COFs have varying pore sizes and topological structures. Thus, target analytes smaller than the pores of the COFs can enter the frameworks and interact with them during separation. On the other hand, target analytes larger than the pores of the COFs cannot enter the frameworks and interact with them during separation; thus, they can be separated. 2) The interactions between the target analytes and side chains (e. g., hydrophobic interactions, hydrogen bonding, π-π interactions, etc.) of the COFs. Since COFs usually contain alkyl side chains, aromatic structures, and oxygen and/or nitrogen atoms with high electronegativity, various interactions could occur between the COFs and target analytes. Finally, directions for the future development and strategic application of CEC based on COF stationary phases are proposed. We believe that future research in CEC based on COF stationary phases should focus on the following aspects: 1) The use of cheminformatics to design and construct COFs to improve the efficiency of COF capillary column preparation; 2) the development of milder methods to synthesize COFs that can meet the requirements of high performance COF capillary columns; and 3) in-depth research to explore the separation mechanism of CEC based on COF stationary phases to provide theoretical guidance for developing CEC methods suitable for the separation and analysis of complex samples.

Multidisciplinary studies with mutated HIV-1 capsid proteins reveal structural mechanisms of lattice stabilization

HIV-1 capsid (CA) stability is important for viral replication. E45A and P38A mutations enhance and reduce core stability, thus impairing infectivity. Second-site mutations R132T and T216I rescue infectivity. Capsid lattice stability was studied by solving seven crystal structures (in native background), including P38A, P38A/T216I, E45A, E45A/R132T CA, using molecular dynamics simulations of lattices, cryo-electron microscopy of assemblies, time-resolved imaging of uncoating, biophysical and biochemical characterization of assembly and stability. We report pronounced and subtle, short- and long-range rearrangements: (1) A38 destabilized hexamers by loosening interactions between flanking CA protomers in P38A but not P38A/T216I structures. (2) Two E45A structures showed unexpected stabilizing CANTD-CANTD inter-hexamer interactions, variable R18-ring pore sizes, and flipped N-terminal β-hairpin. (3) Altered conformations of E45Aa α9-helices compared to WT, E45A/R132T, WTPF74, WTNup153, and WTCPSF6 decreased PF74, CPSF6, and Nup153 binding, and was reversed in E45A/R132T. (4) An environmentally sensitive electrostatic repulsion between E45 and D51 affected lattice stability, flexibility, ion and water permeabilities, electrostatics, and recognition of host factors.

Adenine-based metal–organic framework with 1 D narrow channel for molecular-sieving separation of n-butane and isobutane

Molecular-sieving separation of isomeric C4 paraffins, n-butane (n-C4H10) and isobutane (iso-C4H10), is highly desired but challenging because of their very close molecular sizes and physical properties. However, most of the MOF adsorbents often undergo framework flexibility or ligand rotation or swing, leading to the variation of pore size and the loss of the molecular-sieving effect. In this work, an adenine-based MOF with a suitable window size and rigid narrow 1D channel, namely IPM-101, was selected for n-C4H10/iso-C4H10 separation. Adsorption experiments demonstrate that IPM-101 can sensitively adsorb n-C4H10 in the low-pressure region (0–0.05 bar) and reach a saturation state at 0.1 bar while iso-C4H10 is excluded by the size-exclusion effect. Owing to the high porosity, IPM-101 exhibits a high n-C4H10 adsorption capacity (51.6 cm3 g−1) at 1 bar and 298 K. Density functional theory (DFT) calculations clearly reveal the molecular-sieving mechanism that n-C4H10 molecule can diffuse into the pore channel of IPM-101 easily but the diffusion of iso-C4H10 in IPM-101 is kinetically forbidden for its high diffusion energy barrier. The breakthrough experiments show that n-C4H10 and iso-C4H10 can be efficiently separated and iso-C4H10 with a purity of up to 99.9 % can be directly collected. The regeneration experiments show that IPM-101 has good cycling stability for n-C4H10 adsorption and n-C4H10/iso-C4H10 separation. Therefore, the high separation efficiency, excellent regeneration ability, and low cost indicate that IPM-101 has great application potential for practical n-C4H10/ iso-C4H10 separation in industry.

Mesoscopic framework in hierarchical Pt/Silicate-1 zeolite catalyst enables stable low-temperature CO conversion

Hierarchical porous zeolites often exhibit improved diffusion and enhanced catalytic performance compared to conventional microporous zeolites. Meanwhile, metal encapsulation in a zeolite framework becomes an efficient way to achieve a highly dispersed and stable metal loading for heterogeneous catalysts. Herein, we synthesize a hierarchical Silicate-1 (S-1) zeolite catalyst with three-dimensional mesoscopic channels, which achieves both improved diffusion and uniform encapsulation of Pt species. We find that the optimized zeolite possesses atom-precise mesoscopic channels (2 and 4 nm) formed during the controlled crystallization process, which enables a better catalytic performance (100% CO conversion at a low temperature of ∼60 °C for over 250 h) compared with other mesoscopic S-1 catalysts with varied pore sizes and also superior to micropore-only S-1 with an even smaller Pt size. This unique channel structure enables a balance between maximizing the effective encapsulation of Pt and prohibiting aggregation of Pt species, further broadening the scope of hierarchical porous zeolite catalysts.

Design, Fabrication and Characterization of Multi-Yolk@Shell NiCuFe2 O4 @mSiO2 Mesoporous Nanocomposite Spheres for the Synthesis of Pyrimido-Quinolines under Solvent-Free Conditions.

Multi-yolk@shell mesoporous silica spheres are becoming more and more attractive as high-performance catalysts because of their high surface areas, variable pore sizes, and low densities. In this work, a NiCuFe2 O4 magnetic core with a shell of mesoporous silica mesoporous has been prepared in an easy two-step procedure. The prepared multi-yolk@shell NiCuFe2 O4 @mSiO2 spheres were characterized by using FT-IR, XRD, VSM, EDX, BET, FE-SEM and HR-TEM techniques. These unique multi-yolk@shell NiCuFe2 O4 @mSiO2 spheres demonstrated high catalytic activity for the synthesis of pyrimidoquinolines. Also, this method exposes obvious benefits such as catalyst recyclability, easy reaction condition, simplicity of work up, high product yields and short reaction times.