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The "Chemical Society Reviews" journal, published by The Royal Society of Chemistry, features a variety of research articles on topics such as metal oxide catalysis, nanoplasmonic biosensors, and stretchable optoelectronic materials. The journal covers a range of subjects related to chemistry, including environmental sustainability, bioelectronic interfaces, and energy conversion. Researchers interested in cutting-edge developments in the field of chemistry may find valuable insights in this publication. [Extracted from the article]

Four new Ni16 molecular wheels with the general formula [L4Ni16(RCOO)16(H2O)x(MeOH)12‐x] (where H4L=1,4‐bis((E)‐((2'‐hydroxybenzyl)imino)methyl)‐2,3‐naphthalenediol, and R=H or Me) have been isolated and structurally characterised. Complexes C1−C3 (R=Me) were formed using nickel (II) acetate and presented as polymorphs with the same formulation of charged components. The same wheel‐like architecture was observed in C4 (R=H), which was prepared using nickel (II) formate, demonstrating the potential for further versatility of the system. In contrast to similar four‐fold symmetric Ni(II) wheel clusters, measurements of the static magnetic properties of C1 indicated the presence of dominant antiferromagnetic interactions and an S=0 ground state. [ABSTRACT FROM AUTHOR]

Molecular cavities formed by π‐conjugated component(s) generally, tend to collapse in the absence of guest molecule(s) especially in the solution‐state, because of strong π•••π interactions between molecular components. Recently, we have explored the importance of mutual induced‐fit effect to sort out this issue. In the present report, we have shown the role of substituents on the effectiveness of mutual induced‐fit process in an artificial system. [ABSTRACT FROM AUTHOR]

The gut serves in the digestion of foods, the absorption of nutrients, and the maintenance of the host's health. Intestinal flora maintains a healthy gut by interacting with intestinal cells and inhibiting pathogens from adhering to the gut wall. Probiotics are widely used to regulate intestinal microflora, prevent and treat intestinal disorders,, and promote growth by replacing antibiotics in poultry. The current paper focuses on the effects of probiotics on gut health in general and stress factors that affect probiotic survivability from handling to the host animal's distal intestinal tract. We also go through the various ways of dealing with these stressful factors and methods adopted for industrial use. The use of encapsulation to preserve probiotics has been proven to be effective. The encapsulation strategy directly benefits stability by providing a physical barrier to safeguard them from unfavorable environments. Probiotics have been encapsulated using a variety of approaches. Here, we also discuss the effects of encapsulation on probiotic stability during different stages from processing to animal gut. Choosing the appropriate encapsulating process and encapsulating material during is crucial for producing the best microcapsule as an additive for animal feed, which ultimately improves the animal's intestinal health. [ABSTRACT FROM AUTHOR]

Self-healing approaches are increasingly being explored in various fields as a potential method to recover damaged material properties. By self-recovering without external intervention, self-healing techniques emerge as a potential solution to arrest or prevent the development of large strains problems in soils (e.g., landslides) and other ground effects that influence the serviceability of structures (e.g., differential settlement). In this study, a microcapsule-based self-healing sand was developed, and its performance during mixing and compaction, shearing, and recovery of shear strength was demonstrated. The cargo used for sand improvement, a hardening oil, tung oil, was encapsulated in calcium alginate capsules by the ionic gelation method. The surface properties, internal structure, thermal stability and molecular structure of the capsules were evaluated by advanced material characterization techniques. The survivability of capsules during mixing and compaction was assessed by measuring the content of tung oil released into the sand, while their influence on sand shear strength and its recovery was assessed with shear box tests. The results showed that the capsules could rupture due to movement of the sand particles, releasing the tung oil cargo, leading to its hardening and minimizing its strain-softening response and enhancing up to 76% of the sand shear strength (at a normal stress of 10 kPa and capsules content of 4%). This study demonstrates the potential of a capsules-based self-healing system to provide 'smart' autonomous soil strength recovery and thus with potential to actively control the large strain behavior of soils. [ABSTRACT FROM AUTHOR]

At present, the use of isocyanate adhesives mostly requires the assistance of solvents, which can cause adverse environmental pollution and health effects. The aqueous isocyanate avoids the shortcomings of the solvent, but shortens the working life of the isocyanate. Isocyanate microcapsules can avoid these shortcomings, and can also solidify isocyanate to improve the efficiency of isocyanate use. In this study, microencapsulation technology was used to protect the highly reactive -NCO group, improve the stability of isocyanate, and prolong the working life of isocyanate in water-based wood adhesives. That is, isocyanate microcapsules with gum Arabic/gelatin as shell and isocyanate as core were prepared in oil-in-water emulsion by complex coacervation. In addition, the preparation process was optimized by changing the parameters. Then, the prepared isocyanate microcapsules were characterized and analyzed by Fourier transform infrared spectrometer, Scanning electron microscope, Particle size analyzer, etc. Finally, plywood was prepared by using the prepared isocyanate microcapsules in the wood adhesive. The results showed that, the particle size of isocyanate microcapsules was controllable, and the content of active groups and core in the prepared isocyanate microcapsules can reach a high level. The isocyanate microcapsules extend the working life of isocyanates from about 30 mins to 5 hours, and significantly improve the stability of isocyanates. The bonding strength of the prepared plywood meets the requirements of (Class I plywood) with only 20% -NCO addition. [ABSTRACT FROM AUTHOR]

In this study, an anti-solvent method is employed to encapsulate linseed oil (LO) into phosphorylated ethyl cellulose (P-EC), successfully preparing microcapsules (LO@P-EC). Scanning electron microscopy and Fourier transform infrared spectroscopy experimental results indicate the introduction of phosphoric groups into P-EC, and the successful encapsulation of LO within the microcapsules, which are spherical with an average diameter of 145 μm. Hartmann tests reveal that the introduction of phosphate groups reduces the microcapsule flame propagation height by 43.75% and the average flame propagation speed by 55.67%. Thermodynamic analyses based on the CoatsRedfern equation are performed to determine the changes in activation energy during thermal degradation. Furthermore, fitting analysis shows that the apparent activation energy of microcapsules with shell material of P-EC significantly increases, confirming the evident thermodynamic inhibition of microcapsule deflagration by P-EC. This is mainly attributed to the formation of a char structure by the P-EC shell during combustion, which hinders the progress of the combustion reaction. When immersed in 3.5 wt% NaCl corrosive solution for 15 days, the microcapsule-filled epoxy resin (LO@P-EC/EP) coating exhibits excellent corrosion resistance, which is mainly attributed to the excellent self-healing properties of the microcapsule core LO. [ABSTRACT FROM AUTHOR]

Calix[4]arenes and calix[4]resorcinarenes are well‐known macrocyclic hosts that can be tailored to bind guests of very different natures, including anions, cations, and various neutral molecules. The molecular architectures of the hosts can be altered in many ways: by attaching polar or hydrophilic groups, extending inner cavities with enlarged aromatic side walls, and adding H‐bonding sites to promote the formation of molecular capsules. The attachment of different types of redox‐active moieties renders calix[4]arene and calix[4]resorcinarene derivatives electrochemically active, enabling them to either control the guest‐binding properties of the receptors or be used as electrochemical sensors. This review will focus on calix[4]arene and calix[4]resorcinarene macrocyclic hosts with appended redox‐active groups, such as ferrocene, tetrathiafulvalene, and quinone. We will discuss molecular receptors that can serve as redox sensors for cations or electron‐deficient molecules or can bind and release their guests controlled by redox or electrochemical stimuli. [ABSTRACT FROM AUTHOR]

Microencapsulation technology is a versatile approach that offers effective protection for core materials while also solving issues such as leakage and interface bonding. In this study, a simple yet efficient method for producing multifunctional fabric coatings has been proposed by utilizing chitosan/silica hybrid microcapsules. The synthesis of the microcapsules was achieved through a combination of the single condensation method and the sol-gel method. These microcapsules were specifically designed to encapsulate octadecane and paraffin. The microcapsules were structured with a core-shell configuration, and the shell was functionalized with both fluoroalkyl silane (FAS) and choline phosphate (CP) grafts. The resulting microcapsules were added to silicone resins to produce multifunctional fabric coatings. The desired coatings improved the hydrophilic and hydrophobic properties of the fabrics, with a hydrophilic side contact angle of less than 10 ° and a hydrophobic side contact angle of up to 156 °. In addition, compared with untreated fabrics, coated fabrics can achieve a temperature difference of over 6 °C, demonstrating certain thermal insulation properties. Moreover, the coated fabric exhibits excellent antibacterial properties, with an inhibition rate of over 98% against Escherichia coli and Staphylococcus aureus. The proposed method provides a promising solution for developing advanced multifunctional fabrics with enhanced properties. [ABSTRACT FROM AUTHOR]

The research of molecular capsules offers high application potential and numerous benefits in various fields. With the aim of forming supramolecular capsules which can be reversibly assembled and dissociated by simple external stimuli, we studied interactions between calixarenes containing urea and carboxylate moieties. To this end two ureido‐derivatives of p‐tert‐butylcalix[4]arene comprising phenylureido‐moieties and diacetate‐calix[4]arenes were prepared. The binding of acetate by ureido‐derivatives of calixarene in acetonitrile was characterized, revealing high affinity of ureido‐calixarenes for carboxylates. This suggested high potential for uniting the complementary calix[4]arenes via H‐bonds between carboxylic groups and urea moieties. The assembly of calixarenes was examined in detail by means of UV, 1H NMR, ITC, DOSY, MS, and conductometry providing insight in the structure‐stability relationship. The tetraureido‐calixarene derivative formed the most stable heterodimers with diacetate‐calix[4]arenes featuring practically quantitative association upon mixing the two calixarene counterparts. The possibility of controlling the formation of the heterodimer by protonating the carboxylates, thereby hindering the interactions critical for capsule assembly, was investigated. Indeed, the reversibility of breaking and re‐forming the heterodimer by addition of an acid and base to the solution containing urea‐ and carboxylate‐derivative calix[4]arene was demonstrated using NMR spectroscopy. [ABSTRACT FROM AUTHOR]

Pullulan is a polysaccharide that has attracted the attention of scientists in recent times as a former of edible films. On the other hand, its use for the preparation of hydrogels needs more study, as well as the formation of pullulan microcapsules as active ingredient release systems for the food industry. Due to the slow gelation kinetics of pullulan with sodium trimetaphosphate (STMP), capsules cannot be formed through the conventional method of dropping into a solution of the gelling agent, as with other polysaccharides, since the pullulan chains migrate to the medium before the capsules can form by gelation. Pullulan microcapsules have been obtained by using inverse water-in-oil emulsions as templates. The emulsion that acts as a template has been characterized by monitoring its stability and by optical microscopy, and the size of the emulsion droplets has been correlated with the size of the microcapsules obtained, demonstrating that it is a good technique for their production. Although some flocs of droplets form, these remain dispersed during the gelation process and two capsule size distributions are obtained: those of the non-flocculated droplets and the flocculated droplets. The microcapsules have been evaluated as vitamin C release systems, showing zero-order release kinetics for acidic pH and Fickian mechanism for neutral pH. On the other hand, the microcapsules offer good protection of vitamin C against oxidation during an evaluation period of 14 days. [ABSTRACT FROM AUTHOR]

Calix[4]arenes and calix[4]resorcinarenes are well‐known macrocyclic hosts that can be tailored to bind guests of very different natures, including anions, cations, and various neutral molecules. The molecular architectures of the hosts can be altered in many ways: by attaching polar or hydrophilic groups, extending inner cavities with enlarged aromatic side walls, and adding H‐bonding sites to promote the formation of molecular capsules. The attachment of different types of redox‐active moieties renders calix[4]arene and calix[4]resorcinarene derivatives electrochemically active, enabling them to either control the guest‐binding properties of the receptors or be used as electrochemical sensors. This review will focus on calix[4]arene and calix[4]resorcinarene macrocyclic hosts with appended redox‐active groups, such as ferrocene, tetrathiafulvalene, and quinone. We will discuss molecular receptors that can serve as redox sensors for cations or electron‐deficient molecules or can bind and release their guests controlled by redox or electrochemical stimuli. [ABSTRACT FROM AUTHOR]

The antibacterial microcapsules were prepared by encapsulating Toddalia asiatica (L.) Lam. extracts with urea–formaldehyde resin. The orthogonal test was designed to investigate the effects of the mass ratio of core and wall materials (Wcore:Wwall), emulsifier concentration, reaction temperature and reaction time on the yield rate and coverage rate of microcapsules, and to obtain the best preparation technology for microcapsules. The single-factor results indicated that the maximum influence factor was the Wcore:Wwall of the microcapsules; the larger the Wcore:Wwall, the easier the microcapsules were to agglomerate; and when the Wcore:Wwall was 0.8:1, the coverage rate reached the maximum value of 11.0%. The waterborne topcoat paint film was prepared by adding the microcapsules in the same content. The yield rate, coverage rate, and microscopic morphology of Toddalia asiatica (L.) Lam. extract microcapsules were analyzed, as well as the effects of microcapsules on the microscopic morphology, optical properties, cold liquid resistance, mechanical properties and antibacterial properties of a waterborne topcoat paint film. Combining the optical properties, cold liquid resistance, physical properties, and antibacterial properties of the waterborne topcoat paint film, the comprehensive performance of the waterborne topcoat paint film with the Wcore:Wwall of 0.8:1 was superior. The gloss was 8.07 GU, color difference ΔE was 9.21, visible light transmittance was 82.90%, resistance to citric acid, ethanol and detergent were grade 1, 2 and 2, respectively, elongation at break was 15.68%, and roughness was 3.407 µm. The antibacterial activity against Escherichia coli and Staphylococcus aureus were 42.82% and 46.05%, respectively. In this study, a waterborne topcoat paint film with a microcapsule-coated plant-derived antibacterial agent as the core was prepared, expanding the application prospect of plant-derived antibacterial microcapsules. [ABSTRACT FROM AUTHOR]

An orthogonal experiment was designed to prepare different UV topcoat microcapsules by adjusting the mass ratio of wall material to core material, HLB value of emulsifier, reaction temperature, and reaction time of UV topcoat microcapsule. By testing the morphology and multiple properties of UV topcoat microcapsules, it was found that the biggest factor affecting the synthesis of UV topcoat microcapsules is the emulsifier HLB value. In order to further optimize the performance of UV topcoat microcapsules, a single-factor experiment was conducted with the emulsifier HLB value as the variable, and it was found that the UV topcoat microcapsules achieved the best performance when the emulsifier HLB value was 10.04. The optimal UV topcoat microcapsules were added to the UV topcoat at different amounts to prepare UV topcoat paint films. Through testing the various properties of the UV topcoat paint film, it was determined that the performance of the UV topcoat paint film was optimal when the amount of UV topcoat microcapsules added to the UV topcoat was 4.0%. The optical properties of the UV topcoat paint film were tested, and the effect of UV topcoat microcapsules on the color difference and glossiness of the UV topcoat paint film was not significant. The tensile and self-healing performance of UV topcoat microcapsules were tested. UV topcoat microcapsules can enhance the toughness of the UV topcoat paint film to a certain extent, suppress the generation of microcracks, and have a good self-healing effect. The results provide experimental support for the preparation of microcapsules using UV coatings as core materials for the self-healing of UV coatings. [ABSTRACT FROM AUTHOR]

Microcapsules loaded with essential oils, namely Litsea cubeba, Cymbopogon nardus and Cymbopogon citratus, in gum arabic and chitosan were prepared to explore their mosquito repelling effects and their antimicrobial function. The encapsulation ratio, along with the materials characterization and release behavior of the essential oils from the microcapsules were studied, together with temperature and time dependences. Mosquito repellency was assessed against Ae. aegypti using the "arm-in-cage" method, and the antibacterial activity was tested against E. coli and S. aureus. The results demonstrated that microcapsules loaded with essential oils were successfully prepared for all three essential oils. Also, the results showed that the highest encapsulation ratio was found for microcapsules loaded with Cymbopogon citratus oil. The microcapsules loaded with all essential oils were effective in prolonging protection time against Ae. aegypti, especially in the case of the Litsea cubeba oil, while the Cymbopogon nardus and Cymbopogon citratus oils yielded the highest antibacterial activity against E. coli and S. aureus. [ABSTRACT FROM AUTHOR]

Agavins are reserve carbohydrates found in agave plants; they present texture-modifying properties and prebiotic capacity by increasing the viability of the intestinal microbiota. Through its hydrolysis, agave syrup (AS) can be obtained and can be used as a sweetener in food matrices. The objective of this work was to evaluate the effect of the variation in the content of agavins and AS on the physical, structural, and viability properties of Saccharomyces boulardii encapsulates incorporated into gelatin gummies. An RSM was used to obtain an optimized formulation of gelatin gummies. The properties of the gel in the gummy were characterized by a texture profile analysis and Aw. The humidity and sugar content were determined. A sucrose gummy was used as a control for the variable ranges. Alginate microcapsules containing S. boulardii were added to the optimized gummy formulation to obtain a synbiotic gummy. The viability of S. boulardii and changes in the structure of the alginate gel of the microcapsules in the synbiotic gummy were evaluated for 24 days by image digital analysis (IDA). The agavins and agave syrup significantly affected the texture properties (<1 N) and the Aw (>0.85). The IDA showed a change in the gel network and an increase in viability by confocal microscopy from day 18. The number of pores in the gel increased, but their size decreased with an increase in the number of S. boulardii cells. Agavins and cells alter the structure of capsules in gummies without affecting their viability. [ABSTRACT FROM AUTHOR]

Microfluidics has been applied in the preparation of monodisperse droplets and microcapsules due to its high encapsulation efficiency, its ability to create uniform particle sizes, and its capacity to control core–shell ratio and structure. To bring to the fore methodologies for the fabrication and application of monodisperse microcapsules using microfluidics, we present a review of the design, structure, materials, and surface modification techniques of various microfluidic chips. The review also covers fabrication methods, operating parameters and regulation methods of single and multiple monodisperse emulsion droplets fabricated from various microfluidic devices. Our findings show that particle size of monodisperse droplets depend mainly on microchannel characteristic size and flow rate, with particle size increasing with larger microchannel but decreasing with higher continuous phase flow rate. We additionally reviewed and compared various fabrication methods for monodisperse microcapsules, such as interfacial polymerization, free-radical polymerization, ionic cross-linking, and solvent evaporation. We further reviewed and examined the application of monodisperse microcapsules in biology applications, food engineering, composite materials development, and pharmaceutical industry. We found that high-throughput microfluidics for scale-up monodisperse microcapsule preparation towards uniform degradation and targeted release properties of monodisperse microcapsules would be key innovative direction for future applications. [ABSTRACT FROM AUTHOR]

We report a sensitive method for comparing weak interactions between aryl rings located on the external surfaces of equilibrating homo‐ and heterodimeric capsules. Two identical self‐complementary resorcin[4]arene tetrabenzoate molecules and one tetramethylammonium cation form in CDCl3 hydrogen‐bonded homodimeric capsules whose exteriors are decorated with four tight pairs of weakly interacting aryl rings. The pair wise mixing of six different homodimers establishes their equilibria with the corresponding heterodimeric species in which two types of aryl rings exert on each other some gentle forces. This equilibrium is significantly shifted either towards homo‐ or heterodimers depending on the nature and location of the substituents in the weakly interacting aryl rings. The thermodynamic favorability or disadvantage of the heterodimerization is determined by stronger or weaker aryl‐aryl attractions in the hetero‐ or homodimeric capsules, respectively. The four‐fold amplification of weak aryl‐aryl interactions on the external surfaces of the equilibrating capsules is responsible for high sensitiveness of our approach. [ABSTRACT FROM AUTHOR]

The assembly of MXene materials into microcapsules has drawn great attentions due to their unique properties. However, rational design and synthesis of MXene-based microcapsules with specific nanostructures at the molecular scale remains challenging. Herein, we report a strategy to synthesize N/P co-doped MXene hollow flower-like microcapsules with adjustable permeability via dual surfactants assisted hydrothermal-freeze drying method. In contrast to anionic surfactants, cationic surfactants exhibited effective electrostatic interactions with MXene nanosheets during the hydrothermal process. Manipulation of dual surfactants in hydrothermal process realized N and P co-doping of MXene to improve flexibility and promoted the generation of abundant internal cavities in flower-like microcapsules. Based on the unique microstructure, the prepared hollow flower-like microcapsules showed excellent performance, stability and reusability in size-selective release of small organic molecules. Moreover, the release rate can be controlled by turning the oxidation state and type of MXene. The strategy delineates promising prospects for the design of MXene-based microcapsules with specific structures. [ABSTRACT FROM AUTHOR]

The hyperdispersant SSS-MPEGA-MA (SMM) is prepared through aqueous polymerization using sodium p-styrenesulfonate (SSS), polyethylene glycol monomethyl ether acrylate (MPEGA) and maleic anhydride (MA) as monomers for dispersing phase change microcapsules (PCM). It is also concluded that the best dispersion effect is achieved when the starting concentration of SMM dispersant in aqueous solution with a solid content of phase change microcapsules of 20% occupies 2% of PCM content. The phase change microcapsules are added to a waterborne varnish with a solid content of 20%, and after adding a certain mass of SMM dispersant dropwise, phase change performance is still found on the film, which is the best with a dispersant concentration of 2%. At the same time, the hyperdispersant SMM can make the phase change microcapsules evenly distributed on the water-based varnish, and the dispersion effect is good without affecting the properties of the paint film itself. [ABSTRACT FROM AUTHOR]

2,4-Dichlorophenoxyacetic acid (2,4-D), a phenoxyalkanoic acid herbicide, is among the most widely distributed pollutants in the environment. 2,4-Dichlorophenol (2,4-DCP), as the main metabolite which frequently detected in the environment resources. The toxicity of 2,4-DCP is more severe than that of its parent 2,4-D at any concentration levels. In this study, removal of 2,4-DCP from aqueous solution using graphene oxide (GO) + Trihexyl(tetradecyl) phosphoniumdecanoate [CYPHOS® IL 103] ionic liquid entrapped in polysulfone (PSF) capsule as an adsorbent (GO/IL/PSF microcapsule) is reported. Various techniques such as X-Ray diffraction, Fourier transform infrared spectroscopy, Field emission scanning electron microscopy and Brunauer-Emmett-Teller have been used to identify and confirm the formation of GO, functional group, surface morphology and surface area of the capsule. The adsorption capacity has been investigated under different experimental conditions including pH (2-10), initial 2,4-DCP concentration (20-100 mg L-1), temperature (293-313 K) and at 250 rpm. It has been found that 97% of 2,4-DCP removed from aqueous solutions with adsorption capacity (qe) of 388 mg.g-1 at optimized experimental conditions. The equilibrium adsorption of 2,4-DCP on capsule can be best described by Langmuir isotherm model, with a maximum adsorption capacity (qmax) of 398 mg.g-1 at room temperature. The adsorption kinetics is well described by the pseudo-second-order kinetic model than pseudo first order model and Freundlich kinetic. These results shows that capsule have promising application for adsorption of 2,4-DCP from aqueous solution.According to desorption research, the IL/GO/PSF may be renewed six times with a 1 N sodium hydroxide solution. IL/GO/PSF microcapsule is appropriate for use in fixed bed columns, which treat huge volume of wastewater. [ABSTRACT FROM AUTHOR]

To obtain dual functions of antibacterial and self-healing of a coating, nano-silver solution microcapsules coated with urea formaldehyde resin were selected for antibacterial agents, and rosin-modified shellac microcapsules coated with melamine formaldehyde resin were selected for repairing agents. The optical, mechanical, antibacterial, self-healing, and other physicochemical properties of the coatings were analyzed. The method of adding two microcapsules independently did not affect the coating's hardness. When the primer was prepared by self-healing microcapsules and the topcoats were prepared by antibacterial microcapsules, the hardness of the prepared coatings was maintained at 3 H, with the adhesion up to class 2, the impact strength up to 18 kg·cm, and the roughness as low as 1.144 µm. The elongation at fracture of the coatings prepared by adding microcapsules independently was improved by 2.2%. The self-healing microcapsules release the repair agents to improve the mechanical properties of the coatings. In terms of the antibacterial properties of the coatings, the method that involves adding the microcapsules independently is better than mixed adding. Against Escherichia coli, the antibacterial rate of coatings prepared by adding microcapsules independently reached 82%. Against Staphylococcus aureus, the antibacterial rate of coatings reached 83.3%. At the same time, the self-healing rate was up to 41.1%. The two microcapsules were added to the water-based coating independently to obtain antibacterial and self-healing functions with good comprehensive properties. By modifying coatings on the Andoung wood (Monopetalanthus spp.) with antibacterial microcapsules and self-healing microcapsules, it is possible to obtain good antibacterial properties, further protect the wood substrate, and broaden the application range of functional coatings. [ABSTRACT FROM AUTHOR]

The encapsulation of active components is currently used as common methodology for the insertion of additional functions like self-healing properties on a polymeric matrix. Among the different approaches, polyurea microcapsules are used in different applications. The design of polyurea microcapsules (MCs) containing active diisocyanate compounds, namely isophorone diisocyanate (IPDI) or hexamethylene diisocyanate (HDI), is explored in the present work. The polyurea shell of MCs is formed through the interfacial polymerization of oil-in-water emulsions between the highly active methylene diphenyl diisocyanate (MDI) and diethylenetriamine (DETA), while the cores of MCs contain, apart from IPDI or HDI, a liquid Novolac resin. The hydroxyl functionalities of the resin were either unprotected (Novolac resin), partially protected (Benzyl Novolac resin) or fully protected (Acetyl Novolac resin). It has been found that the formation of MCs is controlled by the MDI/DETA ratio, while the shape and size of MCs depends on the homogenization rate applied for emulsification. The encapsulated active compound, as determined through the titration of isocyanate (NCO) groups, was found to decrease with the hydroxyl functionality content of the Novolac resin used, indicating a reaction between NCO and the hydroxyl groups. Through the thorough investigation of the organic phase, the rapid reaction (within a few minutes) of MDI with the unprotected Novolac resin was revealed, while a gradual decrease in the NCO groups (within two months) has been observed through the evolution of the Attenuated Total Reflectance—Fourier-Transform Infrared (ATR-FTIR) spectroscopy and titration, due to the reaction of these groups with the hydroxyl functionalities of unprotected and partially protected Novolac resin. Over longer times (above two months), the reaction of the remaining NCO groups with humidity was evidenced, especially when the fully protected Acetyl Novolac resin was used. HDI was found to be more susceptible to reactions, as compared with IPDI. [ABSTRACT FROM AUTHOR]

In this work, electrodeposited Ni-Co self-healing nanostructure coatings have been synthesized by utilizing a novel polyureaformaldehyde/SiO2 (PUF/SiO2) hybrid shell with a core of linseed oil. The synthesis of the coating was accomplished by electrodeposition on a carbon steel substrate, using saccharin to refine the crystalline size in the coating. Ni-Co nanostructure coating with and without capsules was then characterized by scanning electron microscope (SEM), energy-dispersive spectroscopy (EDS), x-ray diffraction (XRD), and laser-induced breakdown spectroscopy (LIBS). The anti-corrosion performance of the coating was evaluated by electrochemical testing methods such as open-circuit potential (OCP), linear polarization (LP), electrochemical impedance spectroscopy (EIS), and immersion testing per ASTM G31-72. SEM and XRD results confirm the presence of capsules in the coating and formation of nanocrystalline and single-phase solid solution of fcc crystalline structure. The corrosion analysis indicated that a Ni-Co coating with a higher amount of capsules in the plating bath resulted in enhanced corrosion resistance and better performance in the immersion test. This may be due to the presence of capsules on the surface of the coating and release of linseed oil during the corrosion test. [ABSTRACT FROM AUTHOR]

Summary: Hard capsules are a frequently used oral medication delivery form. This study aims to evaluate the potential of tilapia fish gelatine as a suitable material for hard capsules, by analysing various gelatine properties under different extraction temperatures (50, 60, 70, and 80 °C) and extraction periods (6 and 12 h). The results showed a range of values for the gelatine yield (22–33% (w/w)), gel strength (141–360 g), molecular weight distribution (140–300 kDa), and amino acid composition (185–220/1000 residues). FG70‐12 (296) and FG60‐6 (266) were found to have gel strength between 200 and 300 g thus suitable to be used as hard capsule material. Interestingly, the strongest gelatine having 360 g gel strength obtained from FG50‐6 (fish gelatine extracted at 50 °C for 6 h) became the essential ingredient for preparing hard capsules because two times dipping was enough to obtain the standard weight and thickness. A slight loss of moisture was identified during drying and rapid dissolution (4–8 min) detected from fish gelatine capsule at pH 6.8 or below. Therefore, hard capsules for pharmaceutical applications could be developed from fish gelatine as an alternative gelatine with similar properties as commercial hard capsules and satisfying the pharmacopoeia standard. [ABSTRACT FROM AUTHOR]

Microcapsules encapsulating functional components have been widely applied in smart coating, but there was little literature about the relationship between the dispersion of embedded microcapsules and the coating performances. In this work, a series of microcapsules with different shell chemical structures were prepared via photo‐polymerization, and the relationship between the microcapsule shell component, the dispersion state in coating system and the coating properties were systematically investigated. The dispersion of microcapsule was investigated by measuring rheological behavior and SEM images. The dispersion of the microcapsules was closely correlated with the similarity between the chemical structure of the microcapsule shell and the coating matrix, and higher structural similarity facilitated a more uniform dispersion state of microcapsules in the coating matrix. The dispersion state of the microcapsules directly affected the physical properties and anticorrosion performance of the coating. The uniform dispersion of microcapsules could minimize the negative impact on the composite coating performance, whereas the agglomerated microcapsules destroyed the compactness of the composite coating, thus heavily impairing the basic properties and anti‐corrosion performance. [ABSTRACT FROM AUTHOR]

Cyclodextrins have been utilized as molecular capsules in pharmaceutical application. Cyclodextrin dimers exhibited the property of including larger compounds than cyclodextrin monomers. The fabrication of cyclodextrin dimers is challenging as it involves complicated synthesis and purification techniques. In this study, cyclodextrin dimers were synthesized via a facile procedure using the Diels–Alder reaction to construct a linker between two cyclodextrin units. Furan-substituted γ-CD and maleimide-substituted α-CD and γ-CD were efficiently synthesized in high yields. The furan- and maleimide-substituted cyclodextrins combined to form the desired dimers in water at 25 °C. The dimers disassembled at 75 °C via the retro-Diels–Alder reaction yielding furan and maleimide cyclodextrin monomers, confirmed using 1H NMR spectroscopy. The γ-CD-γ-CD dimer exhibited a high binding constant for tropaeolin OO due to having a wider and more suitable cavity than the monomers. The Diels–Alder reaction can be an efficient strategy for constructing cyclodextrin dimers possessing inclusion abilities. [ABSTRACT FROM AUTHOR]

Biogenic amines are responsible for transmitting electrical impulses in biological systems and hold immense physiological significance. To detect these amines under physiological conditions, optical sensing methods are favoured due to their simplicity, affordability, and rapid response. Probes based on macrocycles or molecular capsules have proven superior for chemosensing applications due to their unconventional structures and intriguing properties. Here we report the synthesis of a BF2-containing molecular capsule with high luminescence and long lifetimes in solution and in the solid state. The cylindrical cavity in the capsule encompassing polarised Bδ+–Fδ− bonds facilitates the formation of multiple hydrogen bonds with dopamine, and the complexation is signalled through visual changes in colour and fluorescence. The mechanism of interaction was studied using fluorescence and NMR spectroscopy and further supported by molecular dynamics simulations, which revealed that multiple non-covalent interactions between the molecular capsule and dopamine are responsible for stabilizing the inclusion complex. Finally, we demonstrate the use of the molecular capsule as a simple probe by preparing a test strip using a polymer for the sensing of dopamine under various conditions. [ABSTRACT FROM AUTHOR]

Mutual induced-fit is well known process in biological system and playing crucial role in enzymatic catalysis, peptide-bond synthesis, protein synthesis, etc..., proceeds by mutual interactions of two or more than two components. However, in an artificial system, to mimic such process is challenging, especially by purely organic components. In this report, we have shown importance of mutual induced-fit in signal amplification of hydrogen-bonded capsule formation. Two different types of highly flexible ligands (one N-bridged and another triazine-bridged) are used. N-bridged tripodal ligand acting as clip over the adduct obtained from triazine-bridged ligand, bringing the resultant adduct in the cone-shape conformation. The resulting cone-shape conformation undergo solvent polarity dependent hydrogen-bonded capsule formation as a sole product. In absence of N-bridged tripodal ligand, only 50% capsule formation is observed through ¹H NMR at 100 mM concentration. However, in the presence of N-bridged tripodal ligand, organic components undergo mutual interactions to opt the cone-shape conformation and 100% capsule is formed (independent of concentration). The complete process is characterized by IR-spectra, ¹H and 13C NMR spectra, concentration dependent ¹H NMR titration spectra, ¹H-¹H COSY, ¹H-¹H NOESY, DOSY NMR, high resolution ESI mass spectra, and also by energy-minimized structure. [ABSTRACT FROM AUTHOR]

Aerogels are a class of materials that have gained increasing attention over the past several decades due to their exceptional physical and chemical properties. These materials are highly porous, with a low density and high surface area, allowing for applications such as insulation, catalysis, and energy storage. However, traditional aerogels, such as pure silica aerogels, suffer from brittleness and fragility, which limit their usefulness in many applications. Herein, we have addressed this problem by using organosilicon compounds, namely polymethylsilsesquioxane derivatives, for the synthesis of aerogel-like materials. Specifically, we have developed a novel approach involving surfactant-free synthesis of microcapsules from partially PEGylated hyperbranched polymethylethoxysiloxane. Due to the highly diphilic nature of these compounds, they readily concentrate at the oil/water interface in aqueous emulsions encapsulating oil droplets. During the subsequent condensation, the organosilicon precursor is consumed for hexane encapsulation (yielding hollow microcapsules) followed by the formation of a continuous condensed phase. Concurrently, methyl groups ensure the hydrophobicity of the resulting materials, which eliminates the need of using additional reagents for their hydrophobization. [ABSTRACT FROM AUTHOR]

Microcapsules are small particles that can effectively protect a core material from degradation. Microcapsules with double capsule walls can improve stability and reduce breakage due to the fact that the physical and chemical properties of double-walled materials can complement each other, thus enhancing the quality and applicability of a microcapsule. Microcapsules can achieve controlled release of core materials by using a temperature-sensitive wall material. In this research, gelatin was used as the inner wall material for these double-walled microcapsules. The outer wall material was a composite material prepared by the reaction of a hydroxyl group in gum arabic with an amino group in N-isopropylacrylamide (NIPAM) in the presence of N, N'-methylene bisacrylamide (BIS), while lavender fragrance oil served as the core material. A complex coalescence method was used for the preparation of microcapsules with double capsule walls. The effects of different proportions of gum arabic to NIPAM on the core loading, microcapsule yield and thermal stability of microcapsules were studied in detail. Additionally, the stability of these fragrance microcapsules with double capsule walls in different solvents and pH values was evaluated. The sustained release properties and mechanism of cotton fabrics treated with prepared fragrance microcapsules were investigated. The results show that the microcapsules prepared with a 10:1 ratio of NIPAM to gum arabic have good temperature responsiveness. Therefore, clothing treated with microcapsules with temperature-sensitive wall materials can ensure that the human body has a fresh and pleasant smell in the case of perspiring in summer. [ABSTRACT FROM AUTHOR]

Alginate encapsulation is a well-known technique used to protect microorganisms from adverse conditions. However, it is also known that the viscosity of the alginate is dependent on its composition and degree of polymerization and that thermal treatments, such as pasteurization and sterilization, can affect the structure of the polymer and decrease its protection efficiency. The goal of this study was to evaluate the protective effect of encapsulation, using alginates of different viscosities treated at different temperatures, on Lactiplantibacillus plantarum 299v under in vitro gastrointestinal conditions and cold storage at 4 °C and −15 °C, respectively. Steady- and dynamic-shear rheological tests were used to characterize the polymers. Thermal treatments profoundly affected the rheological characteristics of alginates with high and low viscosity. However, the solutions and gels of the low-viscosity alginate were more affected at a temperature of 117 °C. The capsules elaborated with high-viscosity alginate solution and pasteurized at 63 °C for 30 min provided better protection to the cells of L. plantarum 299v under simulated gastrointestinal and cold storage conditions. [ABSTRACT FROM AUTHOR]

Purpose: As an efficient self-healing intelligent material, the encapsulation-based self-healing resin mineral composite (SHC) has a broad application prospect. Design/methodology/approach: Aiming at the cracking performance of SHC, the dynamic load condition is employed to replace the traditional static load condition, the initial damage of the material is considered and the triggered cracking process and influencing factors of SHC are analyzed based on the extended finite element method (XFEM). In addition, the mechanism of matrix cracking and microcapsule triggered cracking process is explained from the microscopic point of view, and the cracking performance conditions of SHC are studied. On this basis, the response surface regression analysis method is used to obtain a second-order polynomial model of the microcapsule crack initiation stress, the interface bonding strength and the matching relationship between elastic modulus. Therefore, the model could be used to predict the cracking performance parameters of the microcapsule. Findings: The interfacial bonding strength has an essential effect on the triggered cracking of the microcapsule. In order to ensure that the microcapsule can be triggered cracking normally, the design strength should meet the following relationship, that is crack initiation stress of microcapsule wall < crack initiation stress of matrix < interface bonding strength. Moreover, the matching relationship between elastic modulus has a significant influence on the triggered cracking of the microcapsule. Originality/value: The results provide a theoretical basis for further oriented designing of the cracking performance of microcapsules. [ABSTRACT FROM AUTHOR]

Subphthalocyanines (SubPcs) are aromatic chromophores with a bowlshaped structure and outstanding optoelectronic properties. The cavity formed by a C3-symmetry trispyridyl-SubPc, Pd(II)-metalloorganic capsule has proved an optimal, shape-complementary space for the complexation of C60. Taking advantage of the intense green light absorption of the SubPc components of the capsule, and their ability to transfer energy/electrons from the excited state, our group has recently described the unprecedented use of SubPc cages as molecular photoreactors to perform photoredox-triggered addition of diphenylamine radicals over encapsulated C60. Unfortunately, the reaction could only be performed using stoichiometric amounts of the cage due to inhibition of the SubPc cavity by the addition compound. Here, we describe the preparation of a more flexible SubPc cage built with a related C1-symmetry trispyridyl-SubPc (C1-SubPc-cage), which could facilitate the exchange between the complexed addition compound and pristine fullerene, thus allowing to use it in catalytic amounts. After assessing the ability of C1-SubPc-cage to host C60, the addition of α-aminoalkyl radicals in the presence of the cage under green light irradiation was tested. Curiously, optimisation of the reaction conditions (using catalytic amounts of C1-SubPc-cage in diluted solutions) rendered a different reaction outcome, that is, a cyclopropanated fullerene, in remarkably high yields. [ABSTRACT FROM AUTHOR]

A mixture of multiwalled carbon nanotubes (CNTs) and carbonyl iron powder (Iron(0) pentacarbonyl, CIP) was used as a core material, and a melamine-formaldehyde resin was used as a wall material to prepare CIP/CNTs microcapsules. A core-wall ratio, content of CNTs in the core material, stirring speed, and reaction time were carried out to explore the most significant factor affecting the coverage rate and yield of microcapsules. The most important factor affecting the preparation of CIP/CNTs microcapsules was the content of CNTs in the core material. The optimized CIP/CNTs microcapsules were mixed with shellac microcapsules, and the optimal ratio was explored by analyzing their optical, mechanical, and electromagnetic wave absorption properties in order to prepare coatings with superior performance. The lower the addition amount of CIP/CNTs microcapsules, the lower the effect on the color difference of the coating. The gloss and adhesion of waterborne wood paint coatings decreased with increasing CIP/CNTs microcapsule addition. The hardness, impact resistance and tensile properties of the coatings showed a tendency of increasing and then decreasing with the addition of CIP/CNTs microcapsules. The surface roughness of the coating basically tended to increase with the increase of CIP/CNTs microcapsule content. When the content of added CNTs in the core material was 3.0% and the content of microcapsules was 9.0%, the coating had the highest elongation at break of 12.4% and the highest repair rate of 34.3%, respectively. The mixed shellac microcapsules and CIP/CNTs microcapsules achieved a theoretical minimum reflection loss of −13.52 dB at 16.2 GHz, and the electromagnetic wave absorption band of less than −5 dB was 15.3 GHz–18.0 GHz. The results provide technical references for the preparation of self-healing composite electromagnetic wave absorption coatings on wood substrates. [ABSTRACT FROM AUTHOR]

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The design of porous microcapsules with selective mass transfer and mechanical robustness for enzyme encapsulation is highly desired for biocatalysis, yet the construction remains challenging. Herein, we report the facile fabrication of porous microcapsules by assembling covalent organic framework (COF) spheres at the interfaces of emulsion droplets followed by interparticle crosslinking. The COF microcapsules could offer an enclosed aqueous environment for enzymes, with size‐selective porous shells that allow for the fast diffusion of substrates and products while excluding larger molecules such as protease. Crosslinking of COF spheres not only enhances the structural stability of capsules but also imparts enrichment effects. The enzymes encased in the COF microcapsules show enhanced activity and durability in organic media as verified in both batch reaction and continuous‐flow reaction. The COF microcapsules offer a promising platform for the encapsulation of biomacromolecules. [ABSTRACT FROM AUTHOR]

The design of porous microcapsules with selective mass transfer and mechanical robustness for enzyme encapsulation is highly desired for biocatalysis, yet the construction remains challenging. Herein, we report the facile fabrication of porous microcapsules by assembling covalent organic framework (COF) spheres at the interfaces of emulsion droplets followed by interparticle crosslinking. The COF microcapsules could offer an enclosed aqueous environment for enzymes, with size‐selective porous shells that allow for the fast diffusion of substrates and products while excluding larger molecules such as protease. Crosslinking of COF spheres not only enhances the structural stability of capsules but also imparts enrichment effects. The enzymes encased in the COF microcapsules show enhanced activity and durability in organic media as verified in both batch reaction and continuous‐flow reaction. The COF microcapsules offer a promising platform for the encapsulation of biomacromolecules. [ABSTRACT FROM AUTHOR]

This study aimed to prepare tea tree oil-β-cyclodextrin microcapsules using an optimized coprecipitated method. The impact of the volume fraction of ethanol in the solvent system for microencapsulation on encapsulation efficiency was investigated and analyzed sophisticatedly. Super-high encapsulation efficiency was achieved when a 40% volume fraction of ethanol was used for the microencapsulation procedure, where the recovery yield of microcapsules and the embedding fraction of tea tree oil in microcapsules were as high as 88.3% and 94.3%, respectively. Additionally, considering the operation cost, including time and energy consumption, an economical preparation was validated so that it would be viable for large-scale production. Based on the results of morphological and X-ray diffraction analysis, the crystal structure appeared to differ before and after microencapsulation. The results of gas chromatography-mass spectrometry and Fourier transform infrared spectroscopy confirmed the successful formation of microcapsules. Furthermore, the antibacterial activity of the fabricated microcapsules was assessed by a simple growth inhibition test using Bacillus subtilis as the study object, and the hydrophilic property was proved by a water contact angle measurement. [ABSTRACT FROM AUTHOR]

The colloidal dispersion in a nonpolar medium is an essential material for electrophoretic displays (EPD) with low‐power consumption. A uniform‐sized superparamagnetic iron oxide nanoparticle (SPION) is a promising candidate for EPD, which exhibits tunable structural color by Bragg diffraction. In this study, the surface of SPION is charged in a nonpolar medium by inverse micelles of Solsperse‐17k, an oil‐soluble polymeric surfactant. A photonic ink of SPION dispersion exhibits simultaneous magnetochromism and electrochromism. The photonic ink is encapsulated via a complex coacervation process, in which double layers of gelatin/gum Arabic form a stable shell for µ‐capsule. The µ‐capsules show tunable structural colors, which depends upon the size of SPION in photonic ink. The increased surfactant content in photonic ink brings about a decrease in µ‐capsule size due to a reduced surface tension. A lowered gelatin concentration during coacervation results in a smaller µ‐capsule, which exhibits an electrical color tunability. Optical characterization using a confocal microscopy enables 3D visualization of the inner structure of µ‐capsules and the formation of particle chain structure of SPION in H‐field. The encapsulated photonic ink exhibits magnetochromism for 1 year, illuminating the long‐term stability of µ‐capsules developed in this study. [ABSTRACT FROM AUTHOR]

In this paper, a chitosan-modified nano-silver solution was used as the core material of an antibacterial agent, and melamine formaldehyde resin was coated onto the core material to obtain the antibacterial microcapsules. The core/wall ratio, the stirring rate, the mass ratio of chitosan to silver ions, and the concentration of the emulsifier were used to carry out four-factor and three-level orthogonal experiments to explore the most significant factors affecting the coverage rate and output of microcapsules and the best preparation technology. The results showed that the concentration of the emulsifier was the most important factor affecting the preparation of microcapsules. The higher the concentration of the emulsifier, the better the dispersed morphology of microcapsules, and the higher the coverage rate, up to 44.0%. The antibacterial coating was prepared by mixing microcapsules with a waterborne primer at a content of 4.0%. Its optical properties, mechanical properties, and antibacterial properties were analyzed. By increasing the concentration of the emulsifier, the gloss of the coating showed a trend of first increasing and then decreasing. When the emulsifier concentration was 2.0%, the gloss of the Andoung wood surface coating reached the maximum value of 21.23%. The influence of emulsifier concentration on the color difference of coating had no obvious law, and it was negatively related to the light transmittance. In terms of mechanical properties, the concentration of the emulsifier is directly proportional to the hardness and impact resistance of the coating, with the maximum reaching 31 kg·cm, and is negatively related to adhesion and roughness. In terms of antibacterial properties, the higher the concentration of the emulsifier, the better the antibacterial properties of the coating. When the concentration of the emulsifier was 4.0%, the antibacterial rates of coating which coated the glass substrate were 71.3% and 80.0% for Escherichia coli and Staphylococcus aureus, respectively. The antibacterial rates of the Andoung wood surface coating reached the maximum, which were 68.4% and 73.2%, respectively, and the antibacterial performance was excellent. In this study, an efficient antibacterial microcapsule for waterborne coatings was prepared, which provided the reference value for the application of antibacterial microcapsules in waterborne coatings. [ABSTRACT FROM AUTHOR]

The release rate of liquid core material from microcapsules is crucial for the surface properties of self-protective metal/liquid microcapsule composite plating coating. However, there is no method to accurately predict the release rate of microcapsules. In this paper, the permeability experiments of different shell membranes and core materials were carried out using the weight loss method, and the permeability model of liquid microcapsules was studied based on a multiple linear regression method. The results show that three-variable mathematical model C, including membrane porosity, the viscosity of core material, and membrane thickness is suitable to describe permeability, and the membrane thickness is the most significant influence factor. Additionally, the accuracy of model C was experimentally verified, and the error of the permeation rate is about 2.06% between predictive and experimental values. [ABSTRACT FROM AUTHOR]

Objective: Hydroxypropyl-β-cyclodextrin (HP-β-CD)/menthyl acetate (MA) microcapsules were developed to overcome the volatile and unstable defects of MA and improve the ease of use and storage. Methods: MA microcapsules were prepared via spray drying using HP-β-CD as the wall material. The embedding rate of MA microcapsules was determined through gas chromatography. The embedding characteristics were studied using phase solubility and nuclear magnetic resonance (NMR). The stability was characterized via differential scanning calorimetry (DSC) and the release and retention rates of MA microcapsules at different temperatures. Results: The embedding rate of HP-β-CD /MA microcapsules was 96.3%. The Gibbs free energy change, enthalpy change and entropy change of the embedding reaction between HP-β-CD and MA were all less than zero, indicating that the embedding process was a spontaneous exothermic reaction. NMR spectra showed that MA entered the cavity of HP-β-CD through the large opening end and interacted with the inner wall of the small opening end. DSC and the release and retention rates of MA microcapsules at different temperatures showed that the stability of MA was significantly enhanced after being embedded in HP-β-CD. Conclusion: The HP-β-CD/MA microcapsules are able to significantly improve the stability of MA and reduce the volatilization of MA. [ABSTRACT FROM AUTHOR]

Polymer coating is one of the most widely used methods to inhibit metal corrosion. However, the continuous generation and aggregation of microcracks inside the coating eventually lead to cracking or damage at the macro level, which greatly damage the mechanical and protective properties of the coating. Therefore, the polyurea‐formaldehyde microcapsules loaded with epoxy resin repair agent in the resin matrix are mixed and dispersed. When microcracks are generated inside the coating, the extension and expansion of microcracks would cause the microcapsules to rupture, thereby releasing the repair agent. The repair agent fills the microcracks under the siphon effect and then repair the microcracks, thereby restoring its mechanical properties, corrosion resistance, and appearance. The weight fraction of microcapsules on the internal bonding strength and anticorrosive performance of the scratched samples are studied under tensile test and salt spray condition, which reveal the coatings with microcapsules in the range of 15–20 wt%, demonstrate the best performance. It is worth noting that the research provides some theoretical support and practical guidance for the study of metal anticorrosive coatings with self‐healing function. [ABSTRACT FROM AUTHOR]

In this study, the antibacterial microcapsules of cinnamon essential oil (CEO) were prepared by complex condensation method. Chitosan quaternary ammonium salt (HACC) combined with gum arabic (GA) was selected as the coated wall material. The optimal preparation conditions of CEO microcapsules (CMSs) were determined by response surface methodology (RSM): the core/wall mass ratio was 1:1, the pH value was 4.5, the mass concentration of CaCl2 was 0.7 wt% and the actual encapsulation rate of microcapsules was 90.72% ± 1.89%. The morphology, size, composition and thermal stability of the prepared CMSs were characterized by scanning electron microscopy (SEM), laser particle size analysis (LPDA), Fourier transform infrared spectroscopy (FTIR), thermogravimetric differential thermal analysis (TG–DTA) and differential scanning calorimetry (DSC). In addition, the in vitro drug release and antibacterial properties of CMS were also evaluated. The results showed that CMS was spherical, with an average particle size of 6.31 µm. The obvious weight loss occurred at 269 °C and the corresponding DSC curve had an obvious exothermic peak at 265.5 °C, which had an increase compared with CEO. Microcapsules can achieve slow release, with the lowest and highest release rates being 19.66% and 49.79%, within 30 days. The drug release curve of essential oil of microcapsules was consistent with a first-order release model named ExpDec1. Based on the above research results, the CMS can effectively improve the stability of essential oil, achieve slow release and prolong the antibacterial effect, indicating its potential applications in food, cosmetics and medicine. [ABSTRACT FROM AUTHOR]

Catalysis inside molecular cages and capsules has attracted an increasing amount of attention over the last decade. While many examples of the catalysis of reactions with cationic intermediates and transition states are known, those with anionic counterparts are scarce. One limiting factor is access to suitably sized cationic iminopyridine‐based cages that are stable towards water and anionic/nucleophilic guest molecules. This study aimed at identifying such suitable cages. In this full paper, we describe the journey that finally led to the synthesis of a novel iminopyridine‐based tetrahedron that can bind larger organic anions with binding constants of up to 850 M−1 in MeCN−d3/H2O=9 : 1. Importantly, it also displays stability in basic aqueous acetonitrile. Surprisingly, investigations towards catalysis of reactions with anionic transition states did not indicate rate accelerations in the presence of the cage. [ABSTRACT FROM AUTHOR]

In this study, we prepared fish oil microcapsules by spray-drying using mesquite gum and chitosan as wall materials, and the encapsulation efficiency, microstructure, and lipid hydroperoxide concentration were evaluated. First, stable mesquite gum (216 nm and −22.3 mV) and mesquite gum/chitosan emulsions (333 nm and +47.9 mV) were produced. The fish oil emulsions were spray-dried, and the mesquite gum microcapsules displayed an encapsulation efficiency of 67.18% while mesquite gum/chitosan microcapsules exhibited an efficiency of 92.92%. The lipid hydroperoxide content of the fish oil microcapsules depended on the composition of the wall material, storage time, and storage temperature. [ABSTRACT FROM AUTHOR]

We have shown in a previous work that the combination of the emulsion solvent evaporation technique and droplet-based microfluidics allows for the synthesis of well-defined monodisperse mesoporous silica microcapsules (hollow microspheres), whose size, shape and composition may be finely and easily controlled. In this study, we focus on the crucial role played by the popular Pluronic® P123 surfactant, used for controlling the mesoporosity of synthesised silica microparticles. We show in particular, that although both types of initial precursor droplets, prepared with and without P123 meso-structuring agent, namely P123+ and P123− droplets, have a similar diameter (≃30 μm) and a similar TEOS silica precursor concentration (0.34 M), the resulting microparticles exhibit two noticeably different sizes and mass densities. Namely, 10 μm and 0.55 g/cm3 for P123+ microparticles, and 5.2 μm and 1.4 g/cm3 for P123− microparticles. To explain such differences, we used optical and scanning electron microscopies, small-angle X-ray diffraction and BET measurements to analyse structural properties of both types of microparticles and show that in the absence of Pluronic molecules, P123− microdroplets divide during their condensation process, on average, into three smaller droplets before condensing into silica solid microspheres with a smaller size and a higher mass density than those obtained in the presence of P123 surfactant molecules. Based on these results and on condensation kinetics analysis, we also propose an original mechanism for the formation of silica microspheres in the presence and in the absence of the meso-structuring and pore-forming P123 molecules. [ABSTRACT FROM AUTHOR]

Micrometer sized capsules are often used as single entities for the encapsulation and release of active ingredients, for example in food, cosmetics, and drug delivery. Important parameters that determine the stability of capsules and the release of reagents contained in them are the dimensions and composition of their shell. Most capsule shells are rather thick, thereby occupying a significant fraction of the capsule volume, or they are rigid, making the capsules fragile. This work introduces viscoelastic capsules with very thin shells of order 10 nm. Despite the thin nature of these shells, they are flexible, self‐healing, yet, for practical applications impermeable even to low molecular weight substances. These shells are formed by ionically crosslinking surfactants that are functionalized with catechol‐derivatives. This work investigates the influence of the number of chelators contained per surfactant and the crosslinking ion on the rheological properties of the membranes and relate it to the mechanical properties of the resulting capsules. This work demonstrates that these shells are impermeable to molecules as small as 340 Da even if loaded with cell culture media, indicating their potential for biomedical applications. [ABSTRACT FROM AUTHOR]

As a significant method to inhibit metal corrosion by blocking the diffusion of corrosive mediums to the metal surface, the anticorrosion coating with a self-healing function can actively repair a damaged structure and improve the anticorrosion performance to better meet actual needs. In this study, "external aid" and "intrinsic triggering" self-healing coatings have been introduced in detail, including the preparation method, healing mechanism and practical applications. The healing of "external aid" is based on the addition components such as microcapsules containing healing agents and functional nanoparticles, whose ability of self-healing shows the independence with the coating resin. But the finitely additive amount may limit the sustainable use of "external aid" components, and the abundant fillers also change the basic physical properties of the coating. On the contrary, the "intrinsic triggering" resins can form the cover layer in the defects owing to the physical or chemical reactions between the polymer chains, along with the unlimited cycles theoretically. By contrast, the small defects or gaps can be repaired gradually through chain reactions, but the large areas of damage may need the quick release of healing additives in "external aid" coating. In this review, the advances of two kinds of self-healing coatings were analyzed to discuss the advantages and disadvantages of various healing technologies, and the challenges of development and prospects were also forecasted to provide useful ideas. [ABSTRACT FROM AUTHOR]