Control Of Porosity Research Articles

Synthesis of the COFs: From Design Principle to Synthetic Reactions

Covalent organic frameworks (COFs) are a new category of materials and developing fast in recent years. COFs present low density, controllable porosity, and high surface area. Based on these merits, COFs have great potential in various applications, such as gas separation and storage, energy storage, catalysis, and many others. In this review, we summarize the synthesis of COFs from the aspects of design principles and synthetic reactions. In particular, we categorize the synthetic reactions of also COFs into six categories and introduce the advantages of each type of reaction. Moreover, we utilize several examples to illustrate how to construct COFs by these synthetic methods. In the end, a future perspective on the development of new synthetic methods for COFs is briefly mentioned.

Engineering Modified Mesoporous Silica Catalysts through Porosity and Surface Acidity Control for Selective Production of DME

DME has been received the attention as a renewable energy due to its thermal efficiencies equivalent to diesel fuel, lower NOx emission, near-zero smoke and non-toxic. DME can be obtained by methanol dehydration over solid acid catalysts or directly from syngas over bifunctional catalysts. The catalytic dehydration of methanol to DME has been widely studied in the literature over pure or modified γ -aluminas (γ-Al2O3) and zeolites. Mesoporous silica has obtained much consideration due to its well-defined structural order, high surface area, and tunable pore diameter. In this work, sulfonic acid and aluminium modified mesoporous silica were synthesized and tested as catalysts for production of dimethyl ether from methanol. The modified silicas were studied utilizing XRD, N2 physisorption, pyridine adsorption, and scanning electronic microscopy. The effects of reaction temperature and water deactivation on the methanol selectivity and conversion to dimethyl ether were investigated. Sulfonic acid modified mesoporous silica showed higher selectivity and stability of DME than that of aluminosilicate. The grafting of mesoporous silica with sulfonic groups displayed much more enhanced hydrothermal stability than Al-MCM-41 and γ-Al2O3.

Porous PLAs with Controllable Density by FDM 3D Printing and Chemical Foaming Agent.

This paper shows how fused decomposition modeling (FDM), as a three-dimensional (3D) printing technology, can engineer lightweight porous foams with controllable density. The tactic is based on the 3D printing of Poly Lactic Acid filaments with a chemical blowing agent, as well as experiments to explore how FDM parameters can control material density. Foam porosity is investigated in terms of fabrication parameters such as printing temperature and flow rate, which affect the size of bubbles produced during the layer-by-layer fabrication process. It is experimentally shown that printing temperature and flow rate have significant effects on the bubbles’ size, micro-scale material connections, stiffness and strength. An analytical equation is introduced to accurately simulate the experimental results on flow rate, density, and mechanical properties in terms of printing temperature. Due to the absence of a similar concept, mathematical model and results in the specialized literature, this paper is likely to advance the state-of-the-art lightweight foams with controllable porosity and density fabricated by FDM 3D printing technology.

Development of Anode-Supported Solid Oxide Fuel Cell by Sequential Tape-Casting and Co-Sintering

Simple and cost-effective technologies to produce solid oxide fuel cells layers require control of thickness, homogeneity, and reproducibility. The manufacturing of a SOFC involves significant ceramic processing challenges to obtain layers with controlled microstructure. Currently, possibly the most common technique for large-scale production of SOFCs is the tape casting. In our study, a co-tape casting process was used to avoid delamination and ensure good adhesion between layers. The process consists of casting a thick anode tape of Ni/YSZ (60/40vol%) on top of a thin electrolyte tape of yttria-stabilized zirconia (YSZ). The slurries of both components were prepared using commercial ceramic powders, organic additives, and solvent. The starting materials were processed in a ball mill, to attain the appropriate homogeneity and viscosity for tape casting. A double doctor blade was used to control the thickness. Thermogravimetric and dilatometric analysis were performed to find the optimized heat treatment to remove the organics and densify the electrolyte while keeping a porous anode. The half-cells were then calcined and sintered at 1450°C/1h, with low heating and cooling rates to prevent cracks due to the different thermal expansion of the layers. The LSM cathode was then deposited by spin-coating and attached to the half-cell at 1100°C/1h. To verify the adhesion, thickness, and porosity of the layers, the sample was analyzed by scanning electron microscope. The electrochemical performance was evaluated by impedance spectroscopy and single cell tests under hydrogen and synthetic air. In this study we demonstrate a facile route to SOFC fabrication by co-casting and co-sintering, with relatively mild sintering conditions, with a good control of layer thickness, porosity and adhesion. Figure 1

High Surface Area Mesoporous Silica Nanoparticles with Tunable Size in the Sub-Micrometer Regime: Insights on the Size and Porosity Control Mechanisms.

Mesoporous silica nanostructures (MSNs) attract high interest due to their unique and tunable physical chemical features, including high specific surface area and large pore volume, that hold a great potential in a variety of fields, i.e., adsorption, catalysis, and biomedicine. An essential feature for biomedical application of MSNs is limiting MSN size in the sub-micrometer regime to control uptake and cell viability. However, careful size tuning in such a regime remains still challenging. We aim to tackling this issue by developing two synthetic procedures for MSN size modulation, performed in homogenous aqueous/ethanol solution or two-phase aqueous/ethyl acetate system. Both approaches make use of tetraethyl orthosilicate as precursor, in the presence of cetyltrimethylammonium bromide, as structure-directing agent, and NaOH, as base-catalyst. NaOH catalyzed syntheses usually require high temperature (>80 °C) and large reaction medium volume to trigger MSN formation and limit aggregation. Here, a successful modulation of MSNs size from 40 up to 150 nm is demonstrated to be achieved by purposely balancing synthesis conditions, being able, in addition, to keep reaction temperature not higher than 50 °C (30 °C and 50 °C, respectively) and reaction mixture volume low. Through a comprehensive and in-depth systematic morphological and structural investigation, the mechanism and kinetics that sustain the control of MSNs size in such low dimensional regime are defined, highlighting that modulation of size and pores of the structures are mainly mediated by base concentration, reaction time and temperature and ageing, for the homogenous phase approach, and by temperature for the two-phase synthesis. Finally, an in vitro study is performed on bEnd.3 cells to investigate on the cytotoxicity of the MNSs.

Responses of the Plant Cell Wall to Sub-Zero Temperatures: A Brief Update.

Our general understanding of plant responses to sub-zero temperatures focuses on mechanisms that mitigate stress to the plasma membrane. The plant cell wall receives comparatively less attention, and questions surrounding its role in mitigating freezing injury remain unresolved. Despite recent molecular discoveries that provide insight into acclimation responses, the goal of reducing freezing injury in herbaceous and woody crops remains elusive. This is likely due to the complexity associated with adaptations to low temperatures. Understanding how leaf cell walls of herbaceous annuals promote tissue tolerance to ice does not necessarily lead to understanding how meristematic tissues are protected from freezing by tissue-level barriers formed by cell walls in overwintering tree buds. In this mini-review, we provide an overview of biological ice nucleation and explain how plants control the spatiotemporal location of ice formation. We discuss how sugars and pectin side chains alleviate adhesive injury that develops at sub-zero temperatures between the matrix polysaccharides and ice. The importance of site-specific cell-wall elasticity to promote tissue expansion for ice accommodation and control of porosity to impede ice growth and promote supercooling will be presented. How specific cold-induced proteins modify plant cell walls to mitigate freezing injury will also be discussed. The opinions presented in this report emphasize the importance of a plant’s developmental physiology when characterizing mechanisms of freezing survival.

Abstract 2637: The use of 3D-printed Polylactic acid scaffolds (PLA) as a substrate for growth of MCF7 human breast cancer cells

Abstract This study focuses on fabrication of large-scale tissue scaffolds from Polylactic acid (PLA) and their feasibility as a substrate for cell growth. The scaffolds were fabricated via combined additive manufacturing and microwave foaming. The benefit of this approach is the ability to generate scaffolds with specific architectures and controllable pore size and porosity. The resulting scaffolds have dual pore networks with porosity in excess of 80% which provide a pathway for both cell growth and circulation of culture media. We sought to determine the capability of these scaffolds to support attachment, growth and viability of the MCF7 human breast cancer cell line, as well as drug sensitivity. For these experiments the PLA scaffolds were sterilized in 24-well plates and 1 x 105 MCF7 cells were seeded into each well and cultured for up to 7 days. Scaffolds were then used for SEM imaging, hoescht-staining, or cell counting and viability measurements after trypsinization. Comparisons of cell numbers detached from the scaffolds vs. the remaining well suggest a proportionally small percentage of cells (less than 5%) attached to the PLA, which is not surprising since the scaffolds lack a solid bottom. However, our imaging data using hoescht-staining of PLA-attached cells pre- and post- trypsinization suggest that traditional trypsinization does not effectively detach cells from the PLA material, and therefore this method cannot be used to accurately determine the proportion of cells growing on the scaffolds. This also reveals a potential limitation for application. SEM imaging confirmed cell attachment, with cell growth in the form of sheets along the struts on the bottom layer, and clusters elsewhere with a size of around 50 micron. Analysis of viability using trypan blue exclusion shows no effect of the PLA material on cell viability. To determine the drug sensitivity of cells grown with the PLA material, we treated MCF7 cells grown in the presence or absence of oleuropein, the main phenolic compound found in olive leaves. Media was collected at 48 hours and 7 days and released LDH measured by a cytotoxicity assay. Our data showed that the PLA material itself did not increase cellular toxicity in the absence of oleuropein treatment. It also confirmed that treatment with 200 ug/ml oleuropein induces the expected cytotoxicity in MCF7 cells grown in the absence of PLA, with no significant difference in oleuropein-susceptibility for cells grown in the presence of PLA scaffolds. Together, our results suggest that PLA scaffolds can support MCF7 cell attachment and growth, with no effect on cell viability or drug-induced cytotoxicity. This provides support for the promise of PLA scaffolds for physiologically relevant cell and tissue culture work. Citation Format: Brenna McAllister, Mohammed Mustafa, Sriharsha Sundarram, Shelley A. Phelan. The use of 3D-printed Polylactic acid scaffolds (PLA) as a substrate for growth of MCF7 human breast cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2637.

Porosity control in silicon nitride‐based support materials toward enhanced gas permeability

AbstractPorous Si3N4 materials in tubular geometry are prepared by slip casting before partial sintering. A variety of material‐ and process‐specific variables and their respective effects on densification and resulting pore morphology are systematically evaluated, focusing on starting powder type, amount of sintering additives, and sintering parameters including temperature and time. An increased β‐Si3N4 content in the starting powder was found to promote the formation of a network of elongated grains exhibiting increased pore diameters, as opposed to a more finely featured pore network obtained from starting materials consisting of α‐Si3N4. Following an iterative evaluation of processing variables, materials exhibiting a characteristic diametral compression strength (C‐ring test) of 163 MPa and a Darcian permeability of 4.7 ⋅ 10−15 m2 at a total porosity of 41% were obtained, corresponding to an increase of over 40% in strength and of over 600% in permeability in comparison to materials obtained by α‐Si3N4 powders at comparable porosities. These results demonstrate that the composition of Si3N4 powders significantly affects the resulting pore structure, and by combining the respective selection of starting materials with finely tuned sintering parameters, materials with superior performance in terms of mechanical properties as well as permeability characteristics are accessible.

Composition of Surface Groups and Adsorption Properties of Activated Carbons Derived from Different Bio-precursors

Activated carbons (AC) are widely used in a variety of applications because of their controllable porosity and surface functionalities. In this work, AC were prepared from different hard woods through one- and two-step pyrolysis/activation for the adsorption of organic pollutants in water. Water vapor was used as the activating agent. The influence of the precursor and preparation methods on the properties of the resulting AC was evaluated through multiple techniques. Temperature-programmed oxidation (TPO) measured the reactivity toward oxygen of chars and AC, while temperature-programmed desorption coupled with mass spectrometry (TPD/MS) revealed functional groups on AC surface. Methylene blue adsorption tests evaluated the adsorption capacity of the prepared AC and the presence of mesopores. Depending on the oxidation reactivity of the char produced by pyrolysis, the resulting AC show different surface composition and adsorption performance. With the increasing char oxidation reactivity, the AC has higher degree of surface functionalization and enhanced adsorption toward methylene blue. In particular, Red Maple char is the more reactive one, followed by Birch and Ironwood. Thus, Red Maple AC prepared through the two-step process, exhibits lower activation yield, higher concentration of surface functionalities and improved methylene blue adsorption. TPO technique could predict the degree of surface functionalization and adsorption properties of the final AC.

Fabrication of kinetically stable micropolymofoam particles and the spontaneous induction of morphological transformation

We report fabrication of low-density polymeric microparticles (micropolymofoam particles [μPFPs]) using the piezoelectric inkjet method. After ejecting a polymer solution prepared by dissolving polymers in a volatile organic solvent, microdroplets are periodically generated through an inkjet nozzle in the air. Rapid evaporation of the solvent as it falls through the air leads to a highly porous surface and internal morphology. Optical microscope observation confirms that the inside of the μPFPs is filled with air. Notably, the use of more than two different polymers results in kinetically stable particles, in which the heterogeneous polymer chains are randomly entangled. Shape transformation of the kinetically stable μPFPs occurs upon adding a swelling solvent, spontaneously changing their geometry from porous and rugged-shaped to a Janus-like structure with a clear phase boundary. This transformation is directly monitored using an optical microscope. The surface free energy calculation reveals that particles are transformed to adopt a thermodynamically stable structure; this is achieved by imparting fluidity to the randomly entangled polymer chains, which is energetically unfavorable. In addition, porosity control can be possible by selectively removing one polymer phase of kinetically stable particles comprising two different polymers. Furthermore, the developed inkjet method can be applied for producing composite particles encapsulated with functional nanoparticles and coating or patterning them directly onto a substrate.

Complementary Electrolyte Design for Li Metal Batteries in Electric Vehicle Applications.

A complementary electrolyte system with 0.8 M lithium bis(fluorosulfonylimide) (LiFSI) salt and 2 wt % lithium perchlorate (LiClO4) additive in fluoroethylene carbonate (FEC)/ethyl methyl carbonate (EMC) solution enables not only stable cycling of lithium metal batteries (LMBs) with practical loading (<30 μm lithium anode, cathode loading > 4 mAh/cm2) but also outstanding degradation stability toward the end of cycle life when compared to the conventional electrolyte. Although the use of LiFSI salt can increase the electrolyte conductivity and lengthen the cycle life of LMBs, the aged lithium anode morphology formed by the sacrificial decomposition of LiFSI is highly porous, leading to an abrupt cell capacity drop toward the end of cycling. Moreover, the inability to stop aluminum corrosion by the LiFSI-based electrolyte also causes cracking of the cathode tab during prolonged cycling. It is observed that a highly porous aged lithium consumed electrolyte at a higher rate, leading to the dry-out of electrolyte solvents. On the contrary, dense aged lithium anode morphology increased the localized current applied on the lithium, causing the formation of lithium dendrite. Thus, porosity control is the key to enhance battery performance. In this complementary system, LiClO4 was introduced as an advanced additive to not only improve the capacity retention rate but also mitigate the abrupt capacity drop toward the end of cycle life because LiClO4 acted as a pore astringent reducing the porosity of the aged lithium metal anode to the desired level. Moreover, the addition of LiClO4 can also suppress the Al corrosion, allowing stable high-voltage cycling of LMBs. The synergistic effect of combining LiFSI salt and a LiClO4 additive leads to an electrolyte system that can facilitate the application of high-energy LMBs with practical electrode loading.

In situ X-ray imaging of pore formation mechanisms and dynamics in laser powder-blown directed energy deposition additive manufacturing

Directed energy deposition (DED) additive manufacturing (AM) is receiving growing attention in many applications, such as repair, remanufacturing, and fabrication of functionally graded structures. However, the laser-matter interactions and melt pool dynamics in laser DED with powder flow are still unclear, particularly in how pores form and flow inside the melt pool during the process. Understanding the porosity formation mechanisms is critical in the qualification, certification, and overall properties of a DED AM part. Porosity is a common phenomenon and can significantly hinder the quality of DED fabricated parts, as the pores can act as sites of crack nucleation and propagation. Here, we reveal four types of pore formation mechanisms through in-situ and operando high-speed high-resolution X-ray imaging in the DED AM process. Our results confirm that porosity within the feedstock powder induces pores in the process. We also observed pore formation mechanisms unique to the laser-based, powder-blown DED process as a result of powder delivery, keyhole dynamics, melt pool dynamics, and shield gas. High-speed X-ray images provide direct evidence for pore formation mechanisms and show that the pores related to the interaction between the delivered powder and melt pool are the largest in size in laser-based powder-blown DED AM. These results will guide porosity mitigation, elimination, and control in DED AM.

Heteroatom-doped porous carbon-supported single-atom catalysts for electrocatalytic energy conversion

Electrocatalysts play a crucial role in the development of renewable energy conversion and storage nanotechnologies. The unique advantages of heteroatom-doped porous carbon-supported single-atom electrocatalysts (SAC-HDPCs) are clear. These SAC-HDPCs exhibit outstanding activity, selectivity and stability due to their distinct electronic structure, satisfactory conductivity, controllable porosity and heteroatom-doping effect. Rapid and significant developments involving the synthesis, characterization, and structure-property-function relationship of SAC-HDPCs have been made in recent years. In this review, we describe recent research efforts involving advanced (in situ) characterization techniques, innovative synthetic strategies, and electrochemical energy conversion examples of SAC-HDPCs. The electrocatalytic performance of SAC-HDPCs is further considered at an atomic level, and the mechanisms underlying this performance are also discussed in detail. We expect that these analyses and deductions will be useful for the design of new materials and may help to establish a foundation for the design of future SAC-HDPCs.

The State of the Art of Underwater Wet Welding Practice: Part 2

Developments in underwater wet welding (UWW) over the past four decades are reviewed, with an emphasis on the re-search that has been conducted in the last ten years. Shielded metal arc welding with rutile-based coated electrodes was established as the most applied process in the practice of wet welding of structural steels in shallow water. The advancements achieved in previous decades had already led to control of the chemical composition and microstructure of weld metals. Research and development in consumables formulation have led to control of the amount of hydrogen content and the level of weld porosity in the weld metal. The main focus of research and development in the last decade was on weldability of naval and offshore structural steels and acceptance of welding procedures for Class A weld classification according to American Welding Society D3.6, Underwater Welding Code. Applications of strictly controlled welding techniques, including new postweld heat treatment procedures, allowed for the welding of steels with carbon equivalent values greater than 0.40. Classification societies are meticulously scrutinizing wet welding procedures and wet weld properties in structural steels at depths smaller than 30 m prior to qualifying them as Class A capable. Alternate wet welding processes that have been tested in previous decades — such as friction stir welding, dry local habitat, and gas metal arc welding — have not achieved great success as originally claimed. Almost all of the new UWW process developments in the last decade have focused on the flux cored arc welding (FCAW) process. Part 1 of this paper covered developments in microstructural optimization and weld metal porosity control for UWW. Part 2 discusses the hydrogen pickup mechanism, weld cooling rate control, design, and qualification of consumables. It ends with a description of the advancements in FCAW applications for UWW.

Synthesis and characterization of hexagonal BN-based aerogels for absorbing oils

Porous oil absorbents have been extensively studied in recent years. Boron nitride (BN) is an ideal inorganic material to withstand severe absorption conditions due to its excellent inertness and high-temperature resistance. A large challenge of BN aerogels is their high preparation costs due to requiring high temperatures and dangerous atmospheres. A facial synthesis of h-BN-based aerogels by the cast-freezing method is reported here, which has the advantages of producing a light and recyclable material (~0.035 g/ml) at a low cost and with low energy consumption. In this work, carboxymethylcellulose (CMC) is used as the compounder to interact with BN and form an aerogel that has controllable porosity (38–86 μm) and hydrophobicity (~140°). The porous structure, components, and reaction mechanisms are analyzed by SEM, XRD, mercury porosimetry, etc.. The pore distributions can be controlled by the concentrations of CMC and crosslinking agents. The intercalation effect on BN is carried out by CMC, which increases the specific surface area. Finally, the oil absorption performances are measured. The oil absorption capacity is up to 31.55 g/g (~97% ml/ml) because of the high specific surface area of the prepared material; additionally, the capacity of this material shows no obvious decrease after 6 cycles. Therefore, h-BN-based aerogels are expected to be applied in the oil absorption field and have the potential to be applied in the biochemical and nuclear fields.

Obtainment of the spray-dried extracts of Peperomia pellucida L. (H.B.K.) using different atomization temperatures: physicochemical characterization and technological development for pharmaceutical applications.

Spray-dried extracts are prepared as powders or granules after solvent removal, which can be obtained in the presence or absence of pharmaceutical adjuvants. This work aimed to optimize the process of obtaining dried extracts of Peperomia pellucida L. (HBK) by spray drying. The characterization of the extract was performed by thermal analysis, specific surface area, particle size and high performance liquid chromatography (HPLC); then, capsules were developed for antimicrobial treatment, evaluating four bench lots by the determination of the angle of repose and time of flow, scanning electron microscopy, porosity and physicochemical quality control. There were no significant differences between the extracts obtained by spray drying at atomization temperatures of 140°C, 160°C and 180°C, which was confirmed by thermal analysis. Specific surface area varied inversely with the mean particle size. Regarding the marker content by HPLC, no significant differences were found between the samples, although the flavonoid fraction was more stable at 160°C. Bench lots (I to IV) were developed using the diluents Flowlac®, Starch® 1500, microcrystalline cellulose 250 and Cellactose® 80. Based on the results, the bench lot I, containing Flowlac®, was selected. The results of physicochemical quality control demonstrated that the selected formulation meets the pre-established parameters, and proving to be economically viable.

Photopolymerized Porous Hydrogels.

Hydrogels are polymeric networks highly swollen with water. Because of their versatility and properties mimicking biological tissues, they are very interesting for biomedical applications. In this aim, the control of porosity is of crucial importance since it governs the transport properties and influences the fate of cells cultured onto or into the hydrogels. Among the techniques allowing for the elaboration of hydrogels, photopolymerization or photo-cross-linking are probably the most powerful and versatile synthetic routes. This Review aims at giving an overview of the literature dealing with photopolymerized hydrogels for which the generation or characterization of porosity is studied. First, the materials (polymers and photoinitiating systems) used for synthesizing hydrogels are presented. The different ways for generating porosity in the photopolymerized hydrogels are explained, and the characterization techniques allowing adequate study of the porosity are presented. Finally, some applications in the field of controlled release and tissue engineering are reviewed.

The State of the Art of Underwater Wet Welding Practice: Part 1

Developments in underwater wet welding (UWW) over the past four decades are reviewed, with an emphasis on the research that has been conducted in the last ten years. Shielded metal arc welding with rutile-based coated electrodes was established as the most applied process in the practice of wet welding of structural steels in shallow water. The advancements achieved in previous decades had already led to control of the chemical com-position and microstructure of weld metals. Research and development in consumables formulation have led to control of the amount of hydrogen content and the level of weld porosity in the weld metal. The main focus of research and development in the last decade was on weldability of naval and offshore structural steels and acceptance of welding procedures for Class A weld classification according to American Welding Society D3.6, Under-water Welding Code. Applications of strictly controlled welding techniques, including new postweld heat treatment procedures, allowed for the welding of steels with carbon equivalent values greater than 0.40. Classification societies are meticulously scrutinizing wet welding procedures and wet weld properties in structural steels at depths smaller than 30 m prior to qualifying them as Class A capable. Alternate wet welding processes that have been tested in previous decades — such as friction stir welding, dry local habitat, and gas metal arc welding —have not achieved great success as originally claimed. Al-most all of the new UWW process developments in the last decade have focused on the flux cored arc welding (FCAW) process. Part 1 of this paper covers developments in microstructural optimization and weld metal porosity control for UWW. Part 2 discusses the hydrogen pickup mechanism, weld cooling rate control, design, and qualification of consumables. It ends with a description of the advancements in FCAW applications for UWW.

Ionic Liquid-Based Surfactants: Recent Advances in Their Syntheses, Solution Properties, and Applications.

The impetus for the expanding interest in ionic liquids (ILs) is their favorable properties and important applications. Ionic liquid-based surfactants (ILBSs) carry long-chain hydrophobic tails. Two or more molecules of ILBSs can be joined by covalent bonds leading, e.g., to gemini compounds (GILBSs). This review article focuses on aspects of the chemistry and applications of ILBSs and GILBSs, especially in the last ten years. Data on their adsorption at the interface and micelle formation are relevant for the applications of these surfactants. Therefore, we collected data for 152 ILBSs and 11 biamphiphilic compounds. The head ions of ILBSs are usually heterocyclic (imidazolium, pyridinium, pyrrolidinium, etc.). Most of these head-ions are also present in the reported 53 GILBSs. Where possible, we correlate the adsorption/micellar properties of the surfactants with their molecular structures, in particular, the number of carbon atoms present in the hydrocarbon “tail”. The use of ILBSs as templates for the fabrication of mesoporous nanoparticles enables better control of particle porosity and size, hence increasing their usefulness. ILs and ILBSs form thermodynamically stable water/oil and oil/water microemulsions. These were employed as templates for (radical) polymerization reactions, where the monomer is the “oil” component. The formed polymer nanoparticles can be further stabilized against aggregation by using a functionalized ILBS that is co-polymerized with the monomers. In addition to updating the literature on the subject, we hope that this review highlights the versatility and hence the potential applications of these classes of surfactants in several fields, including synthesis, catalysis, polymers, decontamination, and drug delivery.

Design and Fabrication of Highly Porous Replicated Aluminum Foam Using Double-Granular Space Holder.

Porous materials are widely employed in a wide variety of industrial applications due to their advanced functional performance. Porous aluminum is among the most attractive metallic materials. It can be produced using repeatable methods involving a replicated Al foam that also provides porosity control. In this work, a highly porous replicated Al foam was fabricated. First, the model of multifunctional packing density was used and corrected to select the appropriate space holders. Then, Al foam was produced using a double-granular sodium chloride space holder. The obtained results showed a maximum porosity of 65% that was achieved using a mix of coarse, irregular granules with spherical granules of intermediate size.