Shell Material Research Articles

A novel microencapsulated medium-temperature phase change material employing dicarboxylic acid for thermal energy storage

Microencapsulation enhances the performance of phase change materials (PCMs). However, the existing research on microencapsulation of dicarboxylic acids (DAs) is inadequate, with only one study dedicated to the development of microcapsules containing a low DA content and a shell that decomposes at low temperatures. In this study, glutaric acid (GA), as a representation of DA, was successfully microencapsulated with an enhanced encapsulation ratio. The results obtained by scanning electron microscopy (SEM) revealed a uniform spherical core–shell structure of the microencapsulated GA (MEGA). Fourier transform infrared spectroscopy (FT-IR) an X-ray diffractometer (XRD) analysis confirmed the absence of any chemical reaction between the core and shell materials. Additionally, differential scanning calorimetry (DSC) results demonstrated excellent heat storage. Notably, MEGA exhibited a thermal reliability index of 94.4 % after 200 accelerated thermal cycles. Thermogravimetry analyzer (TGA) results showed good thermal stability of MEGA. The dispersion stability and thermal conductivity of MEGA suspensions displayed significant enhancements compared to those of GA suspensions. Furthermore, compared with the base fluid, the MEGA suspensions with 1.0 wt%, 5.0 wt% and 10.0 wt% demonstrated reduced pumping power requirements by 16.9%, 54.6% and 70.0%, respectively. These findings suggest that MEGA holds promising prospects for applications in the medium temperature energy storage field.

Biosilica-coated carbonic anhydrase displayed on Escherichia coli: A novel design approach for efficient and stable biocatalyst for CO2 sequestration

A robust and stable carbonic anhydrase (CA) system is indispensable for effectively sequestering carbon dioxide to mitigate climate change. While microbial surface display technology has been employed to construct an economically promising cell-displayed CO2-capturing biocatalyst, the displayed CA enzymes were prone to inactivation due to their low stability in harsh conditions. Herein, drawing inspiration from biomineralized diatom frustules, we artificially introduced biosilica shell materials to the CA macromolecules displayed on Escherichia coli surfaces. Specifically, we displayed a fusion of CA and the diatom-derived silica-forming Sil3K peptide (CA-Sil3K) on the E. coli surface using the membrane anchor protein Lpp-OmpA linker. The displayed CA-Sil3K (dCA-Sil3K) fusion protein underwent a biosilicification reaction under mild conditions, resulting in nanoscale self-encapsulation of the displayed enzyme in biosilica. The biosilicified dCA-Sil3K (BS-dCA-Sil3K) exhibited improved thermal, pH, and protease stability and retained 63 % of its initial activity after ten reuses. Additionally, the BS-dCA-Sil3K biocatalyst significantly accelerated the CaCO3 precipitation rate, reducing the time required for the onset of CaCO3 formation by 92 % compared to an uncatalyzed reaction. Sedimentation of BS-dCA-Sil3K on a membrane filter demonstrated a reliable CO2 hydration application with superior long-term stability under desiccation conditions. This study may open new avenues for the nanoscale-encapsulation of enzymes with biosilica, offering effective strategies to provide efficient, stable, and economic cell-displayed biocatalysts for practical applications.

Double emulsion templates for efficient production of phase change microcapsules

The utilization of phase change materials (PCMs) in thermal storage technology exhibits great potential for various applications in thermal management and latent heat storage systems. However, leakage of organic PCMs hinders its practical application. Encapsulation of PCMs in microcapsules with polymer shells can prevent PCM leakage while improving heat transfer and stability. In this study, shell monomers were introduced as an immiscible third phase into the traditional o/w two-phase emulsion system, and the formed three-phase complex emulsion was dynamically reconfigured to exhibit a core–shell encapsulated conformation induced by interfacial tension, resulting in the formation of a thermodynamically stable double emulsion. Microcapsules with 1,6-hexanediol diacrylate (HDDA) shells were successfully prepared using this double emulsion as a template. The emulsion configuration is of significant advantage in promoting stable encapsulation of the phase change material in the shell material, resulting in fast and efficient encapsulation and improved utilization of the phase change material. Phase change microcapsules with different phase change temperatures were prepared and characterized using n-octadecane (C18), methyl stearate (Mes), n-eicosane (C20) and n-docosane (C22) as phase change materials, respectively. Results show that the prepared microcapsules are spherically integrated, with smooth surfaces and obvious core–shell structures, and the enthalpies of phase transition of C18, Mes, C20 and C22 microcapsules are as high as 171.86, 122.37, 165.77 and 178.69 J/g, respectively. These microcapsules exhibit excellent thermal stability and durability and the encapsulation efficiencies exceed 99.7 % at different phase change temperatures. Furthermore, the potential applications of PCM microcapsules in the field of temperature regulation were also demonstrated. This double-emulsion template method provides a straightforward, rapid and scalable approach for the mass production of microcapsules with different core–shell compositions.

Shell-Core Microbeads Loaded with Probiotics: Influence of Lipid Melting Point on Probiotic Activity.

Probiotics have many beneficial physiological activities, but the poor stability during storage and gastrointestinal digestion limits their application. Therefore, in this study, a novel type of shell-core microbead for loading probiotics was prepared through high-precision concentric drop formation technology using gelatin as the shell material and lipids as the core material. The microbeads have a regular spherical structure, uniform size, low moisture content (<4%) and high probiotic activity (>9.0 log CFU/g). Textural testing showed that the hardness of the medium-chain triglyceride microbeads (MCTBs), cocoa butter replacer microbeads (CBRBs) and hydrogenated palm oil microbeads (HPOBs) increased gradually (319.65, 623.54, 711.41 g), but their springiness decreased (67.7, 43.3, 34.0%). Importantly, lipids with higher melting points contributed to the enhanced stability of probiotics during simulated digestion and storage. The viable probiotic counts of the HCTBs, CBRBs and HPOBs after being stored at 25 °C for 12 months were 8.01, 8.44, and 8.51 log CFU/g, respectively. In the simulated in vitro digestion process, the HPOBs resisted the destructive effects of digestive enzymes and gastric acid on probiotics, with a reduction in the probiotic viability of less than 1.5 log CFU/g. This study can provide new ideas for the preparation of intestinal delivery probiotic foods.

The Biological Crystals in Chamid Bivalve Shells: Diversity in Morphology and Crystal Arrangement Pattern

Chamid bivalves are marine organisms that live in high-energy environments and are cemented to hard substrates. To avoid shell damage, the organisms form thick, densely ornamented shells. Shell material consists of aragonite, and the ornamentation may be either aragonitic or calcitic. The latter can be developed as scaly spines, rows of blades, or comarginal, radial arched lamellae. We investigated biological crystal morphology and mode of assembly of Chama arcana and Chama gryphoides shells. Structural characteristics were obtained from electron backscatter diffraction (EBSD) measurements, complemented with laser confocal and BSE imaging. We found a wide range of crystal morphologies and sizes, ranging from irregularly shaped calcite and/or aragonite prisms to tiny and thin aragonite laths. We observed four different modes of crystal assembly patterns: 1. strongly interlocked dendritic calcite units forming the ornamentation blades; 2. aragonite laths arranged to lamellae forming the outer shell layer, the layer adjacent to the calcite; 3. aragonite laths arranged into blocks comprising inner shell layers or aragonitic ornamentations; and 4. shell portions consisting of aragonite prisms, structured in size and crystal orientation, at muscle attachment sites. These four different types of crystal arrangements were observed for the shells of the investigated chamid species; however, they had slightly different strengths of structuring and slight variations in crystal organisation. Additionally, we observed unique microstructural features in Chama shells: We report ornamentation crystals resembling idiomorphic calcite and novel, twinned entities found at the changeover between the aragonitic layers. We highlight and discuss these differences and anomalies in this contribution.

Microencapsulation of tomato oleoresin using tomato waste fibre and its application for orange juice fortification

SummaryFood waste by‐products contain many bioactive compounds, such as proteins, carbohydrates, polyphenols and carotenoids. The purposes of this study was to extract oleoresin from tomato waste, apply tomato pomace powder (TPP) as a new shell material for encapsulation of oleoresin and to fortify orange juice using the developed microcapsules. Microencapsulation was carried out based on different TPP (2% and 3%) and oleoresin (20% and 30%) concentrations by spray drying at two temperatures (130 and 140 °C). Different features of microcapsules such as the encapsulation load, encapsulation efficiency, moisture content, hygroscopicity, bulk and tapped densities and the Hausner ratio were analysed. Based on properties of microcapsules, samples containing 3% TPP and 30% oleoresin dried at 130 °C were selected as the best treatment and their characteristics such as morphology, chemical structure and thermal behaviour were investigated. Scanning electron microscopy indicated that spherical micron‐size particles were formed and their crack‐free fine surface showed their potential for encapsulation of anti‐oxidants to reduce oxygen diffusion. Microencapsulated oleoresin was then added to the orange juice and the samples' pH, acidity, total soluble solids and colour were evaluated and compared with pure orange juice. Free radical scavenging method was used to investigate the anti‐oxidant properties of orange juice during storage. The results indicated that at the end of the 30 days of storage the fortified orange juice had anti‐oxidant activity equal to pure fresh orange juice on day one. Sensory evaluation results showed no significant differences between appearance, colour, thickness and overall acceptance of fresh and the fortified juices (P &lt; 0.05). The results of this study showed the potential application of food and agricultural waste in production of value‐added ingredients to be used as natural additives in food industries.

A cylindrical shell comprising multifunctional metamaterial cores with ultra-low frequency vibroacoustic reduction and mechanical performances

Deep-sea submersible is an important part of oceanic equipment, where special operating environment must require the outer material to have multifunctional properties such as load-bearing, buckling, and vibroacoustic suppression. Here, we proposed a novel metamaterial with excellent mechanical and ultra-low frequency vibroacoustic characteristics as a core material for cylindrical shells used in deep-sea submersibles. Compared to honeycomb materials, the proposed metamaterial utilized the design principles of local resonance theory, incorporating a subwavelength structure periodically embedded within the porous honeycomb structure. This configuration was expected to result in superior static and dynamic properties. Then, we systematically discussed the mechanical and vibroacoustic performance of sandwich cylindrical shells with metamaterial cores, characterized by positive or negative Poisson's ratios, to explore their potential for engineering applications in submerged pressure-resistant structures. The respective unit cells were designed to have equivalent load-bearing capabilities, and simulations were conducted to analyze the physical characteristics related to pressure resistance, buckling, and wave reduction. The results indicated that, compared to conventional honeycomb structures, the metamaterials based on PMMA could safely withstand hydrostatic pressures of nearly 7 MPa, resulting in nearly a twofold increase in structural strength. Additionally, the proposed metamaterials could open bandgaps in an ultra-low frequency range (with the normalized frequency Ω as low as 0.013) and an ultra-wide frequency range (with the bandwidth ratio as high as 83.50%), attributable to the coupling effect of traveling waves and subwavelength units. It is worth noting that the robustness and hydrostatic pressure insensitivity of the metamaterial were demonstrated in the studied hydrostatic pressure range of 0.1 MPa to 5 MPa. This work verified the feasibility of coupling the design between local resonance theory and porous structures, and provided guidance for the multifunctional design of sandwich cylindrical shells.

Development of a novel Al-Si microcapsules with heat-resistant, high latent heat, and efficient solar heat absorption

Aluminum-silicon (Al-Si) alloys are prominent in high-temperature thermal storage due to their high thermal storage density, thermal conductivity, and low cost. Despite their potential, the corrosivity and chemical activity from their liquid phase leakage limit broader applications. The hydrothermal method, often used for encapsulating Al-Si into microencapsulated phase change materials (MEPCMs), consumes the core material, reducing latent heat values. Additionally, the inability to modify the shell material fails to meet multifunctional demands. Addressing solar thermal application needs, we developed a novel heat-resistant, high-latent-heat Al-Si MEPCMs using a “double-layer coating, sacrificial inner layer” approach. This method, originally proposed by our research group and first extended to the microencapsulation of high-temperature phase change materials (PCM), uses Al-12Si as the core, PMMA as the sacrificial layer, and SiO2 as the outer shell.The MEPCMs demonstrated an encapsulation efficiency of 90.7 % and a latent heat value of 454.9 J/g. By adjusting the core–shell ratio, the size of the internal void was optimized to enhance thermal performance and cyclic stability, with MEPCM-S3 maintaining 98.6 % of its latent heat (439.5 J/g) after 10 thermal shocks and 300 thermal cycles. Furthermore, surface loading of carbon black (CB) enhanced the spectral absorption rate to 87.72 % in the 200–2500 nm range, marking an 11 % increase. These modifiable, high-latent heat, and cycle-resistant Al-Si MEPCMs hold broad prospects for applications in high-temperature thermal storage and as next-generation efficient solar energy storage media.

Acceleration of chondrogenic differentiation utilizing biphasic core-shell alginate sulfate electrospun nanofibrous scaffold

Engineering new biomedical materials with tailored physicochemical, mechanical and biological virtues in order to differentiate stem cells into chondrocytes for cartilage regeneration has garnered much scientific interest. In this study, core/shell nanofibrous scaffold based on poly(ɛ-caprolactone) (PCL) as a core material and alginate sulfate (AlgS)-poly(vinyl alcohol) (PVA) blend as shell materials (AlgS-PVA/PCL) was fabricated by emulsion electrospinning. In this vein, the influence of AlgS to PVA ratio (30:70, 50:50), organic to aqueous phase ratio (1:2, 1:3 and 1:5) and acid concentration (0, 10, 20, 30, 40 and 50 %) on nanofibers morphology were investigated. SEM images depicted that AlgS to PVA ratio of 30:70 and 50:50, organic to aqueous phase ratio of 1:3 and 1:5 and acid concentration of 30 % led to uniform, bead-free fibrous mats. AlgS-PVA/PCL scaffolds with AlgS to PVA ratio of 30:70 and organic to aqueous phase ratio of 1:3, showed admirable mechanical features, high porosity (>90 %) with desirable swelling ratio in wet condition. In vitro assays indicated that the AlgS-PVA/PCL scaffold surface had desirable interaction with stem cells and promotes cells attachment, proliferation and differentiation. Thus, we envision that this salient structure could be an intriguing construction as a cartilage tissue-engineered scaffold.

Heat-treated alginate-polycaprolactone core-shell nanofibers by emulsion electrospinning process for biomedical applications

Fabrication of Core-shell nanofibrous mat which is a promising tool for a wide range of applications in tissue engineering can be developed using water in oil (W/O) or oil in water (O/W) emulsion electrospinning. In this study, for the first time, we fabricated an O/W emulsion-based electrospun core-shell mat using polycaprolactone (PCL) as a core and the blend solution of alginate (Alg) and polyethylene oxide (PEO) as shell material. To achieve a stable core-shell mat, firstly, Alg was modified with heat treatment to decrease the molecular weight of Alg. Then, to improve the chain flexibility of Alg, PEO as a second polymer was added to facilitate its electrospinnability. The different volume ratios of O/W were then fabricated by adding PCL to the Alg-PEO solution to find an optimized emulsion solution. The morphology, swelling, and porosity of the construct were evaluated. At the same time, the mechanical characteristic of fibers was evaluated in both dry and wet conditions. This study also examined cell-scaffold interactions to address the need for a scaffolding material to be suitable for tissue engineering and biomedical applications. Finally, the result exhibited a distinct core-shell structure with better mechanical properties compared to the Alg-PEO.

Damping characteristics of High-Temperature superconducting pinning maglev levitation system

High-temperature superconducting (HTS) pinning maglev has achieved rapid development in recent decades. The levitation system of the HTS pinning maglev is mainly composed of Dewar with built-in HTS bulks and permanent magnet guideway (PMG). For a maglev transportation system, damping is important for vibration attenuation, and the inherent damping characteristics of the HTS pinning maglev system have not been evaluated clearly. In this paper, the damping characteristics of the HTS pinning maglev system are analyzed through experiments and simulations. Experiments are conducted to measure the dynamic responses of the system under free and forced vibrations. The logarithmic envelope method is used to evaluate the system damping under free vibration. The cross-correlation function is utilized to obtain the phase difference between the system vibration signal and excitation signal, and then calculate the system damping under forced vibration conditions. In addition, a two-dimensional finite element model including HTS bulks, PMG, and Dewar conductive shells is established to evaluate the damping force generated by each component during system vibrations. The additional eddy current damping of the conductive Dewar shell is considered and analyzed. Finally, from the perspective of system damping and thermal stability of HTS bulks, suggestions for selecting Dewar shell materials are proposed.

Performance investigations on fluorine-rubber-tube-laying pumping wet shotcrete filled with microencapsulated phase change materials

The challenge of mitigating adverse climatic conditions is a critical issue that affects worker safety and operational efficiency in underground engineering. This study introduces an innovative approach using pumping wet shotcrete as an insulating material, incorporated with microencapsulated phase change materials (MPCMs) and filled within fluorine rubber tubes to address this concern. The MPCMs were synthesized via suspension polymerization, utilizing paraffin as the core material and modified SiO2-poly (lauryl methacrylate) as the shell material. To determine the optimal composition for practical application, an orthogonal experimental design was employed, complemented by comprehensive performance testing. The results indicated that a mix of 1375 kg/m3 of sand, 120 kg/m3 of ceramsite, and 1 g/cm of SiO2-MPCMs in each fluorine rubber tube having an inner diameter of 13 mm, provided the best balance between multiple properties. Notably, the insulation performance improved by 60–75 % compared to traditional pumping wet shotcrete, demonstrating a significant enhancement in thermal management capabilities. The findings contribute substantially to the field of thermal management in mines, presenting a novel technique that could be instrumental in improving safety and efficiency in deep underground operations.

Developments and thermal properties of thermochromic microcapsule and thermochromic asphalt-based composite coatings

The black appearance of asphalt pavement easily absorbs a large amount of solar radiation in hot summer to lower its anti-deformation ability, and asphalt pavement cools down quickly in cold winter to cause cracks. To solve these problems, thermochromic core material (TCM) was encapsulated by the shell material of urea-formaldehyde (UF) resin to prepare thermochromic microcapsule (TM) using situ-polymerization. Then the surface morphology, particle size distribution, chemical composition, phase change property and thermal stability of TM were characterized. After that, emulsified asphalt and acrylic emulsion were selected as film-forming substances to prepare thermochromic asphalt-based composite coating (TACC) after adding different dosages of TM. The surface morphology, chemical composition, thermal storage capacity, phase change property and spectral reflectance of TACC were studied. The results show that TCM is successfully encapsulated by shell material which restricts the thermal conductivity of TCM, making heat transfer process of TM become gentler. Also, the phase change property of TM is still better due to excellent phase change property of TCM. Further, TM particles with the size range of 3.2–4.8 μm are uniformly distributed on TACC surface and show better dispersion in emulsified asphalt. Additionally, TM enhances the thermal storage capacity and thermal stability of TACC. The heat exchange efficiency between asphalt pavement and surrounding environments is increased by added TM particles, improving the thermal stability of TACC. Finally, the increased spectral reflectance in the near-infrared region reflects more solar radiation in hot season because of high reflectivity of TACC on asphalt pavement, which lowers asphalt pavement temperature to improve its anti-deformation ability.

Synthesis and performance optimization of CsPbBr3/CdS core/shell lead halide perovskite nanocrystals by an ion exchange method

All-inorganic lead halide perovskite nanocrystals (NCs) have excellent optoelectronic properties and promising applications. Improving the stability of inorganic halide NCs and optimizing their photoluminescence quantum yields (PLQY) has become an urgent task. Constructing core-shell structures is an effective method to improve the environmental stability and PLQY, however, realizing core-shell structured perovskite NCs with good dispersion and multiple perovskites encapsulated within the shell material remains challenging. In this work, CdS shells were grown on the surface of CsPbBr3 NCs by ion-exchange method utilizing perovskite NCs with their ionic properties, and the effectiveness of the surface shell protection is reflected in its enhancement of long-term storage stability, storage stability in water, and thermal stability of NCs. In addition, the PLQY and exciton binding energies of CsPbBr3/CdS NCs are increased. Finally, the NCs were packaged into green emitting LED devices and performed high stability. The results will facilitate the further commercialization of all-inorganic lead halide perovskite materials for optoelectronic devices.

Construction of Reverse Type-II InP/ZnxCd1-xS Core/Shell Quantum Dots with Low Interface Strain to Enhance Photocatalytic Hydrogen Evolution.

The InP-based quantum dots (QDs) have attracted much attention in the field of photocatalytic H2 evolution. However, a shell should be used for InP-based photocatalytic systems to passivate the numerous surface defects. Different from the traditional InP-based core/shell QDs with Type-I or Type-II band alignment, herein, the "reverse Type-II" core/shell QDs in which both the conduction and valence bands of shell materials are more negative than those of core materials have been well-designed by regulating the ratio of Cd/Zn of the alloyed ZnxCd1-xS shell. The reverse Type-II band alignment would realize the spatial separation of photogenerated carriers. More importantly, the photogenerated holes tend to rest on the shell in the reverse Type-II QDs, which facilitate hole transfer to the surface, the rate-determining step for solar H2 evolution using QDs. Therefore, the obtained InP/Zn0.25Cd0.75S core/shell QDs exhibit superior photocatalytic activity and stability under visible light irradiation. The rate of solar H2 evolution reaches 376.19 μmol h-1 mg-1 at the initial 46 h, with a turnover number of ∼2,157,000 per QD within 70 h irradiation.

Self‐lubricating polyamide 6 and polyamide 6.6 microcapsule‐based composites

AbstractPolymeric applications with extended service life and low energy loss due to friction are of great interest in conveyor and power transmission technology. Self‐lubricating systems utilizing microcapsules hold significant potential for increasing energy efficiency and extending the operational life of these applications. This study focuses on synthesizing oil‐filled microcapsules through in situ polymerization of polyamide and their incorporation in polyamide 6 and polyamide 6.6. Microcapsules with a core made of thermally stable lubricant Food Lube, and particle diameter D90 of 50 μm were synthesized and isolated as a free‐flowing powder via spray‐drying procedure. The resulting powder demonstrated high thermal stability (loss of 5% at 350°C) due to the high thermal stability of both core and shell materials. A compounding process utilizing a twin‐screw extruder was developed to blend microcapsules into thermoplastic matrices. An injection molding machine forms tension rods. The composites' tribological properties are assessed through ball‐on‐disc tests conducted in both oscillation and rotation. The friction coefficient and wear rate of the composites experience a reduction of 79% and 56% for polyamide 6, as well as 77% and 75% for polyamide 6.6. Mechanical testing of the microcapsule composites reveals a decrease in mechanical properties.

Enhanced UIO-66@PDA/SA hydrogel composite bead soil conditioner exhibiting good water retention, adsorption and efficient recyclability capabilities

A hydrogel composite bead soil conditioner with water retention, adsorption and recyclability properties was developed. The core material of the beads was metal organic framework material UIO-66, while the shell material consisted of polydopamine (PDA) and sodium alginate (SA). Characterization techniques such as Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Brunauer-Emmett-Teller (BET) were used to analyze and demonstrate the structure and composition of the composites. The water retention experiment and soil water loss experiments showed that the UIO-66@PDA/SA hydrogel composite beads had a water retention rate of 10.96 % after 300 min and a water evaporation rate of less than 1 % in soil within 4 h, indicating good water retention performance. Adsorption experiments showed that the UIO-66@PDA/SA hydrogel composite beads effectively adsorbed methylene blue (MB) with an equilibrium adsorption amount of 213.79 mg/g. This was a 72.6 % increase compared to pure sodium alginate (SA). They had the highest adsorption capacity of 240.79 mg/g at pH=9 and T = 298.15 K, indicating that alkaline conditions favored the adsorption process. The adsorption process followed the Pesudo-second-order model and exhibited characteristics of the Langmuir adsorption isotherm model. In addition, dynamic adsorption analysis demonstrated that the UIO-66@PDA/SA hydrogel composite beads owned efficient recyclability, and the relative adsorption efficiency remained above 90 % after 4 cycles. This technology offers a cost-effective, uncomplicated, and efficient solution for promoting a healthy soil environment and facilitating agricultural applications.

Application of Johnson's approximation in finite element modeling for electric field‐dependent materials

AbstractJohnson's approximation is implemented in a finite element code to simulate the electric field dependence of a core–shell microstructure material. We show how the microstructure, based here on a 50:50 volume fraction, influences the measured effective permittivity as a function of applied voltage. Using a Johnson's parameter of β = 1.0 × 1010 Vm5/C3, verified from commercial BaTiO3‐based multilayer ceramic capacitors (MLCC), we show how the microstructure and the difference in core and shell conductivities alter the local fields generated and how this influences the voltage dependence of the effective permittivity. Systems that comprise a conductive core‐like material surrounded by a resistive shell experience little or modest voltage dependence due to the shell material providing shielding to large electric fields within the cores. Conversely, if the core material is more resistive than the shell material, substantial voltage dependence occurs with simulations showing over a 50% decrease in the effective permittivity. These simulations give improved understanding of voltage dependence and provide a method to help guide the design of future materials for MLCCs with improved performance.

Eco-Friendly Fungal Chitosan-Silica Dual-Shell Microcapsules with Tailored Mechanical and Barrier Properties for Potential Consumer Product Applications.

Commercial perfume microcapsules are becoming popular across the globe to fulfill consumers' demands. However, most of microcapsules rely on synthetic polymers and/or animal-sourced ingredients to form the shells. Therefore, replacement of the shell materials is imperative to minimize environmental microplastic pollution, as well as to meeting peoples' needs, religious beliefs, and lifestyles. Herein, we report a methodology to fabricate environmentally benign dual-shell (fungal chitosan-SiO2) microcapsules laden with fragrance oil (hexyl salicylate). Anionically stabilized oil droplets were coated with fungal chitosan via interfacial electrostatic interactions at pH 2, which were then covered by an inorganic coating of SiO2 produced via external alkaline mineralization of sodium silicate. Core-shell microcapsules with a spherical morphology were achieved. Under compression, dual-shell chitosan-SiO2 microcapsules yielded a mean nominal rupture stress of 3.0 ± 0.2 MPa, which was significantly higher than that of single-shell microcapsules (1.7 ± 0.2 MPa). After 20 days in neutral pH water, only ∼2.5% of the oil was released from dual-shell microcapsules, while single-shell microcapsules cumulatively released more than 10%. These findings showed that the additional SiO2 coating significantly enhanced both mechanical and barrier properties of microcapsules, which may be appealing for multiple commercial applications, including cosmetics and detergents.

Habitat Provision Differs Across Subtidal Reefs Varying in Location Within the Estuarine Landscape

Although position within the estuarine landscape is known to influence structural characteristics and ecological functioning of many habitats, the influence of position on subtidal oyster reef characteristics and functioning is relatively understudied. This study assessed habitat provision by oysters and benthic macrofauna on subtidal bar and patch oyster reefs within the northwestern Gulf of Mexico estuary. Bar reefs had greater and more variable oyster density, biomass, and volume, as well as dead shell material, compared to patch reefs. Benthic macrofaunal community composition differed between reef types, with bar reefs hosting 11× and 30× higher biomass of Porcellanidae and Ampithoidae crustaceans, and patch reefs supporting 34× and 47× higher biomass of Eunicidae annelids and Leptocheliidae crustaceans. The environmental variables most highly correlated with macrofaunal communities on both bar and patch reefs were sediment chlorophyll-a, volume of dead oyster shells, and depth. Despite differences in structural characteristics and position within the estuarine landscape, subtidal oyster reefs are often managed as a single habitat type. Our findings emphasize the importance of considering location in oyster reef conservation and restoration efforts to better predict and optimize faunal provision outcomes.