Emulsion Template Method Research Articles

Porous PEG Scaffold Fabricated via Emulsion-Templating Technique Towards Immobilization of Saccharomyces cerevisiae Cells

The cell immobilization technique, which restricts living cells to a certain space, has received widespread attention as an emerging biotechnology. In this study, a yeast (Saccharomyces cerevisiae)-loaded highly open-cell emulsion-templated polyethylene glycol (PEG-polyHIPE) was synthesized to be a reusable enzymatic catalyst. An emulsion was prepared with polyethylene glycol diacrylate (PEGDA) aqueous solution, cyclohexane, and polyethylene-polypropylene glycol (F127) as the continuous phase, dispersed phase, and surfactant, respectively. Then PEG-polyHIPE was obtained by polymerization of the PEGDA in emulsion. The highly porous materials obtained by the emulsion-templating method are suitable for use as carrier materials for yeast immobilization, due to their favorable structural designability. During the activation process, the yeast S. cerevisiae can readily gain access to the interior of the material via the interconnected pores and immobilize itself inside the voids. The yeast-loaded polyHIPE was then used to ferment glucose for ethanol production. The yeast immobilized inside the polyHIPE has high fermentation efficiency, good recoverability, and storage stability. After seven cycles, the yeast maintained 70% initial fermentation efficiency. The S. cerevisiae kept more than 90% of the initial cellular activity after one week of storage both in the dry state and in yeast extract peptone dextrose medium (YPD) at 4 °C. This study strongly demonstrates the feasibility of using high-throughput porous materials as cell immobilization carriers to efficiently osmotically immobilize cells in polyHIPEs for high-performance fermentation.

Preparation of PDMS permeation membrane by emulsion dilution method and its separation performance for aromatics

Natural aroma compounds are a kind of important food additive. Taking bis(2-ethylhexyl) sodium sulfosuccinate (AOT) as the surfactant, water-in-n-heptane emulsions were prepared. Then, the emulsions were adopted as the diluter to prepare polydimethylsiloxane (PDMS) pervaporation membranes using the emulsion templating method (ePDMS), of which the separation layer was controlled by the template action of emulsion drops. The ePDMS membranes were utilized to separate aroma compounds. Field-emission scanning electron microscope (FESEM) analysis revealed that the surface of the ePDMS membrane remained smooth, and white light interferometry confirmed the membrane’s surface smoothness. FESEM cross-sectional analysis exposed the voids left by the evaporation of the emulsion, rendering the separation layer of the ePDMS membrane more porous. Water contact angle measurements demonstrated the hydrophobicity of the ePDMS membrane, which is advantageous for the pervaporation of aromatic compounds. Fourier transform infrared spectrometry analysis confirmed the evaporation and separation of the emulsion, retaining the original chemical properties of the PDMS membrane. In an ethanol–water system, the permeation flux of ethanol in ePDMS membranes prepared with 1 emulsion (Vwater:Vn-heptane = 1:9; mass concentration of AOT of 1.0 mg/ml) is 90.6% higher than that in PDMS membranes, while the separation factor does not change obviously. The separation performance of ePDMS membranes for linalool in water was further studied. Results show that the permeation flux and separation factor of linalool in ePDMS composite membranes at 50 °C are 786 g m−2 h−1 and 17.69, which separately increase by 84.7% and 27.1% compared with those in PDMS membranes. This indicates that adding ethanol exerts a significant synergistic effect on the separation of linalool.

Single nickel atoms anchored on porous N-doped nanocarbon with dual reaction sites for highly-efficient transfer hydrogenation of furfural to furfuryl alcohol

The non-precious metal single-atom catalysts (SACs) supported on carbon materials for the catalytic transfer hydrogenation (CTH) of α,β-unsaturated aldehydes (UAL) still suffer from the problems of harsh reaction conditions and low activity. In this work, nickel SACs anchored on porous N-doped nanocarbon (Ni1/NC900) with dual reaction sites were synthesized using the high internal-phase emulsion (HIPE) template method combined with impregnation. The Ni1/NC900 catalyst exhibited remarkable catalytic activity for the CTH of furfural (FF) to furfuryl alcohol (FFA), achieving >99.0 % conversion and selectivity at 100 °C for 60 min, with a turnover frequency (TOF) of 2908.1 h−1, surpassing other reported nickel-based catalysts by 1–3 orders of magnitude. The excellent catalytic performance of Ni1/NC900 was attributed to the high mass transfer efficiency (HMTE) of the support and the dual reaction sites of Ni–N4 and pyridinic N, where Ni–N4 as Lewis acidic site for adsorption of FF and isopropanol (i-PrOH), while the adjacent pyridinic N as Lewis basic site for the deprotonation of i-PrOH. The isotope labeling experiments revealed that the hydrogenation of FF was accomplished by proton transfer with i-PrOH, in agreement with the intermolecular hydride transfer mechanism. Furthermore, Ni1/NC900 demonstrated excellent stability and well general applicability, demonstrating its potential for industrial applications. This work provides a reference for the application of carbon-based non-precious metal SACs in the CTH reaction of UAL.

Synthesis of palygorskite based microspheres for efficient and recyclable simultaneous removal of radioactive iodine and iodide

The valence state of radioactive iodine is abundant and convertible. Therefore, it is crucial to synthesize a cost-effective, recyclable adsorbent that can effectively and simultaneously remove polyvalent radioactive iodine. Polymerized microsphere adsorbents (PMs) with pore size of 10 ∼ 20 μm and surface of palygorskite (PAL) were prepared by the Pickering emulsion template method using dimethylaminoethyl methacrylate (DMAEMA) as functional monomer and affordable PAL as matrix material. Under the synergistic effect of chemical adsorption of tertiary amine group in PDEAEMA and physical adsorption, the optimized PM-2 exhibits excellent adsorption activities for gaseous iodine (2.98 g/g), iodine in n-hexane (1.39 g/g), and iodide (1.48 mmol/g). After heating and soaking in NaOH solution, the high adsorption capacity and almost unchanged morphology and crystal structure of PM-2 after 5 cycles indicate that PMs have outstanding physical and chemical stability and reusability. Importantly, PMs also show astonishing adsorption activity for the simultaneous removal of iodine and iodide. Moreover, the ultra-fast adsorption rate and ultra-high adsorption efficiency of PMs provide promising results for the removal of polyvalent radioactive iodine in environmental remediation.

Marine sulfated polysaccharide affects the formation mechanism of gelatin emulsion-based oleogels

Protein-polysaccharide delivery systems function as a promising tool to deliver bioactive ingredients aiming to improve their solubility and bioavailability. In this study, gelatin (Gel) and κ-carrageenan (Car) were used to evaluate the characteristics of the Gel-Car emulsion and the emulsion-templated oleogels. Results showed that Car addition significantly reduced the particle size and increased the potential absolute value during emulsion storage, especially for Gel-0.5% Car and Gel-1.0% Car emulsions, indicating Car addition enhanced the emulsion's stability. The emulsions' rheological results indicated that all the emulsions exhibited weak gel-like behavior dominated by elasticity, suggesting Car addition improved the emulsions' shear resistance and viscoelasticity. The emulsions' instability indices were Gel (0.034), Gel-0.1% Car (0.026), Gel-0.5% Car (0.013), and Gel-1.0% Car (0.011), indicating Car addition enhanced the emulsions' stability. For oleogels, Car addition significantly reduced the oil loss rate, delayed the thermal degradation, and improved the viscoelasticity, shear resistance, thixotropic recovery properties, and high-temperature resistance, especially for Gel-1.0% Car oleogel. The stability analysis exhibited that Car addition improved the oleogels' stability, with Gel-0.5% Car oleogel showing the best stability. FFA release was Gel (25.22%), Gel-0.1% Car (26.86%), Gel-0.5% Car (31.38%), and Gel-1.0% Car (39.57%), suggesting Car addition promoted the rapid release of FFA during oleogels digestion. Results above indicated that Gel-Car oleogels exhibited good structural stability and high gel strength, which provide a theoretical basis and new ideas for the preparation of oleogels from protein-marine sulfated polysaccharides using the emulsion template method for food industrial application.

Facile synthesis and biomimetic amine-functionalization of chitosan foam for CO2 capture

A high-performance biomass-based adsorption materials could be the promising trend for CO2 capture and storage technology. However, the direct application of biomass-based porous materials as a CO2 adsorbent with enhanced performance is an emerging issue. Herein, a facile synthesis and a biomimetic strategy were combined to prepare amine-functionalized chitosan foam for CO2 capture, and then a porous biomass is achieved for the application on the environment protection field. Firstly, the chitosan foam was synthesized by the emulsion-templating method at room temperature. Depended on stabilizing n-octane in the chitosan hydrogel with Span 80, a tunable three-dimensional network porous structure was obtained. Subsequently, co-deposition with dopamine (DA) and polyethyleneimine (PEI) was applied to load abundant amine content on the surface of chitosan foam and thereby improving CO2 adsorption capacity. Finally, the as-prepared amine-functionalized chitosan foam exhibited the impressive adsorption capacity of 3.59 mmol/g at 333 K and atmospheric pressure, and the better adsorption selectivity and stability. The results extend the preparation approach of biomass porous materials, and also its application in CO2 adsorption technology.

Oleogels loaded with lycopene structured using Zein/EGCG/Ca2+ complexes: Preparation, characterization and potential application

Oleogels have attracted considerable attention due to their excellent viscoelasticity and high content of polyunsaturated fatty acid. This study explored the potential of Zein/(−)-epigallocatechin-3-gallate/Ca2+ complexes oleogels loaded with lycopene as potential substitute for solid fats in biscuit formulations. Utilizing an emulsion-templated method, oleogels were prepared and characterized for visual appearance, droplet size, microstructure, and rheological properties. The incorporation of lycopene indicated a dose-dependent effect on these characteristics, achieving optimal properties at a concentration of 0.3 mg/mL. At this concentration, oleogels exhibited higher encapsulation efficiency (> 90 %), lower oil loss (< 2 %), and denser network structures. Rheological analysis highlighted the shear-thinning behavior, gel-like structure, and thixotropic recovery of oleogels. Substituting of margarine with lycopene-loaded oleogels in biscuits yielded products with regular appearance, uniform color, and potential health benefits, demonstrating the viability of these oleogels as a healthier alternative to traditional solid fats in baking.

Structuring low-density lipoprotein-based oleogels with pectin via an emulsion-templated approach: Formation and characterization

Due to the adverse health effects associated with saturated and trans fats, novel oleogels based on egg yolk low-density lipoprotein (LDL) and pectin (PE) as solid fat substitutes were developed using the emulsion-template method. This method involves structuring an oil-in-water emulsion with LDL and PE, followed by evaporation of the aqueous phase, resulting in the entrapment of liquid oil within a crystal network. In addition, the methodology evaluated the impacts of pH and PE/LDL mass ratio on the microstructure, physicochemical properties, and stability of the prepared emulsions and their corresponding oleogels. The PE/LDL complex-based emulsions exhibited small droplet size (9.95 and 9.67 μm), pronounced gel-like structure, and high viscosity and stability at optimum pH (6.0) and PE/LDL ratio (1:5), respectively. FTIR results emphasized that electrostatic interactions played more significant roles than hydrogen bonding in the interactions between the carboxyl group of PE and the amino group of LDL. Besides, the oleogels, based on LDL/PE-stabilized emulsions, showed a unique crystal structure and moderate rheological and textural properties, resulting in an increased oil-binding capacity of 83.74%. In conclusion, the unique aspect of this study was the combination of these biopolymers, which could have great potential for creating oleogels from edible oils using an emulsion-templated method. Thereby, these results could provide a novel approach for producing high-quality oleogels from LDL and PE for food applications.

Dual Anticorrosive and Self-healing Coating Based on Multiresponsive Polyaniline Porous Microspheres.

In this work, a smart self-healing coating with long-term anticorrosion ability was developed based on multiresponsive polyaniline (PANI) porous microspheres. The polyaniline porous microspheres loaded with corrosion inhibitor (benzotriazole, BTA) was prepared by the emulsion template method and photopolymerization. The BTA loaded in the polyaniline microspheres acted as a corrosion inhibitor, while the polyaniline in the shell performed the multiple functions of corrosion inhibition, pH-responsive and photoresponsive release, and photothermal conversion. Owing to the inherent corrosion-inhibiting nature of BTA and PANI, the BTA-loaded polyaniline microsphere could endow coating with dual anticorrosive properties. The coating with polyaniline microspheres did not show any corrosion product after 700 h of salt spray testing, while obvious pitting corrosion could be observed for the blank coating after 100 h of the salt spray test. Thanks to the photothermal properties of PANI, the composite coating exhibited self-healing behavior under NIR light irradiation. The coating with 10 wt % polyaniline microspheres could achieve rapid closure and recover its barrier properties within 5 s of NIR irradiation. And the release of BTA could form a passivation film on scratches to further repair coating defects. The on-command responsive release, high healing efficiency, and excellent anticorrosion properties of this dual self-healing anticorrosion coating provide perspectives on extending the service life of metals.

Synthesis of bulk foam-like palygorskite based adsorbent for efficient and convenient recyclable removal of radioactive iodine and iodide

Radioactive iodine is the inevitable product of nuclear fission, and the types and valence states of iodine are relatively rich and easy to convert to each other. Therefore, the synthesis of a material that can be easily recovered and efficiently remove polyvalent radioactive iodine has great strategic significance for the safe use of nuclear power. Bulk foam-like palygorskite based adsorbents (PDMA-PAL) with the macroscopic pore size of 40 to 150 μm were synthesized by the emulsion template method using dimethylaminoethyl methacrylate (DMAEMA) as the functional monomer and cheap palygorskite (PAL) as the matrix material. The excessive addition of DMAEMA and PAL will lead to the collapse of the porous structure. Optimized PDMA2-PAL shows excellent adsorption capacity (2.14 g/g) for iodine in cyclohexane solution with the equilibrium time of 5 h. PDMA2-PAL also exhibits an excellent adsorption capacity for gaseous iodine (308 wt%), and the I2 adsorption mechanism is the strong affinity and charge transfer of electron-rich N heteroatoms for electron-deficient iodine. PDMA2-PAL also achieves an outstanding iodide adsorption capacity (2.1mmol/g) within 5 min, and the I− adsorption mechanism is the electrostatic interaction between I− and the derivatization of tertiary amine under acidic conditions. Moreover, the deprotonation in alkaline solution can desorb iodide efficiently, which makes PDMA-PAL exhibit excellent recyclability. Importantly, PDMA-PAL also shows excellent simultaneous adsorption ability of iodide and iodine, and also exhibits stable adsorption activity in actual water. This study provides promising results for the removal of polyvalent radioactive iodine by bulk foam-like palygorskite based adsorbent in environmental remediation.

Fabrication of fluorinated superhydrophobic oil-absorption cabins with controllable movement, elasticity, and wear resistance

Superhydrophobic materials that can withstand harsh environments are critical in oil spills. Here, fluorinated superhydrophobic monoliths were prepared in one step based on a high internal phase emulsion (HIPE) templating method. γ-methacryloyloxypropyltrimethoxysilane (KH570)-modified Fe3O4 nanoparticles were added into the emulsion as co-stabilizers and participated in the composition of micro-nano hierarchical structures. The fluorinated alkyl backbone and rough structure enabled the foam to exhibit excellent superhydrophobicity with a water contact angle (WCA) of 153.5° and a sliding angle (SA) of 5.92°. The unique structure and composition of the foam allowed it to maintain stable superhydrophobicity (153.97°) even after severe sandpaper abrasion tests (Drawn 10 m at 7.1 kPa on P400 grit sandpaper). It also demonstrated exceptional hydrophobicity to strong acids, bases, and UV light. The oil-saturated material can be regenerated through a simple extrusion process, showing outstanding reusability. After ten cycles of oil adsorption, the adsorption capacity remains above 90 % of the initial value. The additional magnetic properties of the material enable it to remove oil in confined or hazardous conditions. More importantly, with the assistance of a vacuum pump, the material permits continuous separation of organic solvents from the water. These excellent properties of the foam make it a potential material for treating wastewater.

Preparation of soybean protein isolate–ester emulsifier oleogels and comparative study of their structure and properties

In recent years, oleogel as a viscoelastic semi-solid to replace trans fatty acids and reduce saturated fatty acids in food has received more and more attention. Herein, an emulsion template method was used to produce soybean oil–based oleogels with seven different ester emulsifiers and soy protein isolate as oleogelators. The chemical and physical characteristics of oleogels produced via various crosslinking factors were comparatively examined. Results revealed that all oleogels generated β-type needle crystals and exhibited high oil-holding capacity (>80 %), among which glycerol monolaurate G2 and diacetyl tartaric acid ester of mono–diglycerides G6 exhibited the strongest oil-holding capacity (96.6 % and 96.2 %, respectively). Furthermore, all oleogels exhibited strong thixotropic recovery, high thermal stability, as well as high gel strength (G′ > G′′). Of these, G2 and G6 exhibited the highest thixotropic recovery rates at 74.54 % and 78.19 %, respectively. Additionally, in accelerated oxidation trials, the peroxide value and thiobarbituric acid reactive substances of all oleogels had low oxidation rates, indicating high oxidative stability. These results contribute to a better understanding of oleogels for formulating trans-free and low-saturated foodstuffs with desired physical and functional properties.

Investigating the Potential of CO2 Nanobubble Systems for Enhanced Oil Recovery in Extra-Low-Permeability Reservoirs.

Carbon Capture, Utilization, and Storage (CCUS) stands as one of the effective means to reduce carbon emissions and serves as a crucial technical pillar for achieving experimental carbon neutrality. CO2-enhanced oil recovery (CO2-EOR) represents the foremost method for CO2 utilization. CO2-EOR represents a favorable technical means of efficiently developing extra-low-permeability reservoirs. Nevertheless, the process known as the direct injection of CO2 is highly susceptible to gas scrambling, which reduces the exposure time and contact area between CO2 and the extra-low-permeability oil matrix, making it challenging to utilize CO2 molecular diffusion effectively. In this paper, a comprehensive study involving the application of a CO2 nanobubble system in extra-low-permeability reservoirs is presented. A modified nano-SiO2 particle with pro-CO2 properties was designed using the Pickering emulsion template method and employed as a CO2 nanobubble stabilizer. The suitability of the CO2 nanobubbles for use in extra-low-permeability reservoirs was evaluated in terms of their temperature resistance, oil resistance, dimensional stability, interfacial properties, and wetting-reversal properties. The enhanced oil recovery (EOR) effect of the CO2 nanobubble system was evaluated through core experiments. The results indicate that the CO2 nanobubble system can suppress the phenomena of channeling and gravity overlap in the formation. Additionally, the system can alter the wettability, thereby improving interfacial activity. Furthermore, the system can reduce the interfacial tension, thus expanding the wave efficiency of the repellent phase fluids. The system can also improve the ability of CO2 to displace the crude oil or water in the pore space. The CO2 nanobubble system can take advantage of its size and high mass transfer efficiency, among other advantages. Injection of the gas into the extra-low-permeability reservoir can be used to block high-gas-capacity channels. The injected gas is forced to enter the low-permeability layer or matrix, with the results of core simulation experiments indicating a recovery rate of 66.28%. Nanobubble technology, the subject of this paper, has significant practical implications for enhancing the efficiency of CO2-EOR and geologic sequestration, as well as providing an environmentally friendly method as part of larger CCUS-EOR.

Eco-friendly, highly interpenetrated and slightly swollen pHEMA hydrogel foam for durable underwater superoleophobicity and emulsion separation

Despite the emergence of hydrogels as ideal candidates for preparing the superhydrophilic materials for emulsion separation, their structural stability and swelling still hinder their long-term use, mainly due to structure defects after swelling. Herein, differing from the common modification, the eco-friendly poly 2-hydroxyethyl methacrylate (pHEMA) hydrogel foam was designed and synthesized via a one-step strategy by using the high internal phase emulsion (HIPE) template method, which endowed it with a highly interpenetrated porous structure. Unlike the normal swellable hydrogels such as poly(N-isoproplyacrylamide) (PNIPAM) hydrogel, or modified hydrogel coatings, the pHEMA hydrogel foam displayed stable structure and underwater superoleophobicity after 20 d of immersion in water. The pHEMA hydrogel foam could separate different kinds of highly surfactant-stabilized oil-in-water (O/W) emulsions with a high separation efficiency of 99.3% for liquid paraffin emulsion obtained solely under gravity-driven. Additionally, it exhibited excellent antifouling performance and long-term acid/alkali tolerance over 100 h without decrease in emulsion separation efficiency (98.0%, oil/water ratio of 99:1) and permeation flux (over 2000 L·m−2·h−1) attributed to its stable bulky structure. Moreover, the pHEMA hydrogel foam demonstrated high cell viability of 96.87% and 95.96% after culturing the 3T3 clone A31 cells in the pHEMA hydrogel foam for 24 h and 48 h, respectively, indicating good biocompatibility. Hence, our work provides a new design to develop an eco-friendly bulk hydrogel foam that achieves stable structure and performance for emulsion separation.

Chitosan-Based Oleogels: Emulsion Drying Kinetics and Physical, Rheological, and Textural Characteristics of Olive Oil Oleogels.

Oleogels are of high interest as promising substitutes for trans fats in foods. An emulsion-templated method was used to trap olive oil in the chitosan crosslinked with vanillin matrix. Oil in water emulsions (50:50 w/w) with different chitosan content (0.7 and 0.8% w/w) with a constant vanillin/chitosan ratio (1.3) were air-dried at different temperatures (50, 60, 70, and 80 °C) and freeze-dried (-26 °C and 0.1 mbar) to produce oleogels. Only falling rate periods were determined during air-drying kinetics and were successfully modeled with empirical and diffusional models. At a drying temperature of 70 °C, the drying kinetics were the fastest. The viscoelasticity of oleogels showed that the elastic modulus significantly increased after drying at 60 and 70 °C, and those dried at 50 °C and freeze-dried were weaker. All oleogels showed high oil binding capacity (>91%), but the highest values (>97%) were obtained in oleogels with a threshold elastic modulus (50,000 Pa). The oleogels' color depended on the drying temperature and chitosan content (independent of the drying method). Significant differences were observed between air-dried and freeze-dried oleogels with respect to oxidative stability. Oxidation increased with the air-drying time regardless of chitosan content. The found results indicated that drying conditions must be carefully selected to produce oleogels with specific features.

Natural shellac-based microcapsules as lipase carriers for recyclable efficient Pickering interfacial biocatalysis

Enzyme is an important class of catalyst. However, the efficiency of enzyme-catalyzed reactions is constrained by the limited contact between the enzyme and its substrate. In this study, to overcome this challenge, lipase-loaded microcapsules were prepared from natural shellac and nanoparticles using the emulsion template method. These microcapsules can perform dual roles as stabilizers and enzyme carriers to construct a water-in-oil Pickering interfacial biocatalytic system. The results showed that the hydrolytic conversion of the microcapsules could reach 90% within 20 min, which was significantly higher than that of the traditional biphasic system. The catalytic activity was influenced by the oil-to-water volume ratio and the microcapsule content. The microcapsules remained highly catalytic efficiency even after storage for three months or seven cycles of reuse. These microcapsules were prepared without the use of any cross-linkers or harsh solvents. This green and efficient catalytic system has great application prospects in the food industry.

Preparation of Graphene Oxide/Polymer Hybrid Microcapsules via Photopolymerization for Double Self-Healing Anticorrosion Coatings.

In this work, graphene oxide (GO)/polymer hybrid microcapsule-loaded self-healing agents were prepared via the combination of the emulsion template method and photopolymerization technology. The incorporation of GO in the microcapsule shell not only improved the impermeability, mechanical property, and solvent resistance property of the microcapsules significantly but also endowed the microcapsules with photothermal conversion property. By incorporating GO/polymer hybrid microcapsules in water-borne epoxy resin, a novel kind of anticorrosion coating with a double self-healing property was successfully fabricated. When the coating was scratched, the linseed oil (LO) encapsulated in the microcapsules could fill the crack, and the photothermal conversion property of GO could promote the molecular chain movement of the damaged area under near-infrared (NIR) irradiation to realize the close of the crack. Based on the filling of LO and photothermal conversion-induced scratch narrowing, the "filling" and "close" double self-healing effect can be realized under temporal NIR irradiation, which could lead to the complete recovery of the scratched coating. The |Z|f=0.1Hz value of the damaged coating with GO/polymer microcapsules after double healing was comparable to that of the intact coating, which was about 4 orders of magnitude higher than that of the scratched blank coating and single self-healing coating. As to the neutral salt spray test, the scratched blank coating failed in protection after 100 h, while the healed composite coating did not show any corrosion after 300 h.

Fabrication of microcapsules with graphene/organic hybrid shell based on Pickering emulsions for self‐healing anti‐corrosive coatings

AbstractDuring the utilization of organic coatings, microcracks may arise as a result of external environmental influences and inherent aging, significantly diminishing the coating's lifespan. In this study, we employed the Pickering emulsion template method combined with interfacial polymerization to fabricate graphene oxide/polyurethane/polyaniline (GO/PU/PANI) organic–inorganic hybrid shell microcapsules utilizing isophorone diisocyanate (IPDI) as the core material. The capsules exhibited an average particle diameter of 3.11 μm and an encapsulation rate of 78.19%. Subsequently, these prepared capsules were incorporated into a photocurable resin to obtain a self‐healing corrosion‐resistant coating. Scanning electron microscopy analysis demonstrated that even with just 5% addition of microcapsules, nearly complete repair could be achieved. The tensile strength and flexural strength of the self‐healing material containing 5% microcapsules were measured at 84.8 MPa and 193 MPa respectively. These values represented only a marginal decrease in tensile strength by 2.75% and flexural strength by 5.39%, compared to the substrate without capsule addition. Remarkably, after immersing the repaired coating in a NaCl solution with a concentration of 5 wt% for up to 250 hours, the alternating current impedance value remained stable at approximately 6.9 × 105 Ω·cm2. This outstanding corrosion resistance can be attributed to synergistic effects between PANI and IPDI within the coating system, thereby expanding its potential applications under harsh conditions.

Effects of cellulose diameter on the formation and rheological properties of edible walnut oleogels structured by cellulose nanofiber

Oleogel of edible vegetable oils structured by cellulose nanofiber (CNF) via emulsion-templated method has attracted many interests due to its potential substitute of saturated or trans-fats in food industry. The gelation mechanism of liquid oil is dominated by different intermolecular non-covalent interactions, while the type and strength of these interactions are greatly influenced by the structure and properties of the gelator factors. Here, the effect of different CNF diameter ranges (5–10 nm, 10–20 nm and 20–60 nm) was investigated for CNF-based walnut oil oleogels, under the same fiber length and surface carboxyl content of CNFs. The results showed that CNFs with diameters of <20 nm exhibited better emulsification properties, and effectively restrained droplet size increasing and aggregation, compared to CNF with diameter of 20–60 nm. The resultant oleogels with smaller CNF diameter exhibited higher oil-binding capacity (OBC, ∼85%) and better thermal stability of the resultant oleogels. More compact structure and stronger mechanical strength of oleogels were achieved with CNF diameters of <20 nm, which was verified by stronger textural hardness of the oleogels (0.46 N), as well as higher storage modulus (up to 1.1 × 105 Pa) and apparent viscosity in rheological measurement. The enhanced OBC and structure strength of oleogels with smaller CNF diameter could be attributed to the enhanced hydrogen bonding interactions between CNF molecules and CNFs with oil molecules during oleogelation, as the rigorously fibrillation exposed more surface hydroxyl groups as accessible hydrogen bonding sites during CNF preparation. This study improved the understanding about gelling properties of CNFs with different fiber diameters and provided an empirical basis for the construction of CNF-based oleogels with tunable hydrogen bonding interactions.

Chitin nanocrystals-stabilized emulsion as template for fabricating injectable suspension containing polylactide hollow microspheres

One of the promising applications of rod-like chitin nanocrystals (ChNCs) is the use as particle emulsifier to develop Pickering emulsions. We reported a ChNC-stabilized oil-in-water emulsion system, and developed a Pickering emulsion-templated method to prepare polylactide (PLA) hollow microspheres here. The results showed that both non-modified ChNCs and acetylated ChNCs could well emulsify the dichloromethane (DCM) solution of PLA-in-aqueous mannitol solution systems, forming very stable emulsions. At the same oil-to-water ratios and ChNC loadings, the emulsion stability was improved with increasing acetylation levels of ChNCs, accompanied by reduced size of droplets. Through the solvent evaporation, the PLA hollow microspheres were templated successfully, and the surface structure was also strongly dependent on the acetylation level of ChNCs. At a low level of acetylation, the single-hole or multi-hole surface structure formed, which was attributed to the out-diffusion of DCM caused by the solvent extraction and evaporation. These surface defects decreased with increased acetylation levels of ChNCs. Moreover, the aqueous suspension with as-obtained PLA microspheres revealed shear-thinning property and good biocompatibility, thereby had promising application as injectable fillers. This work can provide useful information around tuning surface structures of the Pickering emulsion-templated polymer hollow microspheres by regulating acetylation level of ChNCs.