Formation Of Pickering Emulsions Research Articles

Correction to: Banana peel nanocellulose and soy protein hydrolysate complexed colloidal nanoparticles synthesis using ultrasonic interventions: characterization and stable pickering emulsion formation

Correction to: Banana peel nanocellulose and soy protein hydrolysate complexed colloidal nanoparticles synthesis using ultrasonic interventions: characterization and stable pickering emulsion formation

Interfacial adsorption dynamics of solid lipid particles at oil/water interfaces through QCM-D technique

The interfacial adsorption dynamics of solid particles are important processes in the formation of Pickering emulsion, and its stabilities and functionalities are critically dependent on the particle interfacial structures. In this study, we investigated the interfacial behaviors of solid lipid particles (SLPs) within six food-grade SLPs using the quartz crystal microbalance with dissipation (QCM-D) technique. These SLPs had been subjected to surface modification with varying emulsifier contents, specifically 1, 2, and 4 wt% of both Polysorbate 40 (T40) and sodium caseinate (Na-Cas), referred to as T40-SLPs and Na-Cas-SLPs. Two distinct interface behaviors have been identified: Type 1, characterized by with weak interfacial activity, which included the 1 and 2 wt% T40-SLPs, and Type 2, exhibiting stronger interfacial activity, encompassing the 4 wt% T40-SLPs as well as the 1, 2 and 4 wt% Na-Cas-SLPs. Subsequently, the mechanism through which the emulsifiers influenced the interfacial dynamic behaviors was established by correlating the interfacial behaviors with the properties of SLPs. Briefly, larger and more electronegative spherical Na-Cas-SLPs exhibited stronger interfacial activity, which facilitated the formation of smaller and more stable Pickering droplets. The interfacial films formed by the short plate-like T40-SLPs were not sufficiently consolidated, which led to instability of the hydrophobic interfaces. These results were confirmed with macrostability tests of the Pickering emulsions stabilized by the SLPs and are expected to provide basic information for the functionalization of multicomponent Pickering emulsions.

CO2-Triggered Hierarchical-Pore UiO-66-Based Pickering Emulsions for Efficient and Recyclable Suzuki-Miyaura Cross-Coupling in Biphasic Systems.

Hierarchical-pore metal-organic frameworks (H-MOFs) are considered to be emerging stabilizers for Pickering emulsion formation because of their hierarchically arranged pores, tailorable structures, and ultrahigh surface areas. However, stimulus-triggered Pickering emulsions built by H-MOFs have been seldom presented to date despite their great significance in diverse applications. Herein, by grafting Pd(OAc)2 on the hierarchical-pore zirconium MOF UiO-66, namely, H-UiO-66, with the aid of 1-alkyl-3-methylimidazolium 2-cyanopyrrolide salts ([CnMIM][2-CN-Pyr], n = 4, 6, and 8), a series of Pd(OAc)2-[CnMIM][2-CN-Pyr]@H-UiO-66 have been developed and utilized as emulsifiers for constructing CO2-switching Pickering emulsions. It was found that Pd(OAc)2-[CnMIM][2-CN-Pyr]@H-UiO-66 was able to stabilize the n-hexane-water mixture to form a Pickering emulsion even at an amount of 0.5 wt %. Upon alternate addition of CO2 and N2 at normal pressure, Pickering emulsions could be smartly converted between demulsification and re-emulsification. Through combining varieties of spectroscopic techniques, the mechanism of the switchable phase transformation lay in the acid-base reaction of ionic liquids with CO2 on H-UiO-66 and the creation of more hydrophilic salts, which reduced the wettability of the emulsifier and destabilized the emulsion. As an example of application, the stimulus-triggered Pickering emulsion was employed as a palladium-catalyzed Suzuki-Miyaura cross-coupling microreactor to achieve the combination of chemical reactions, isolation of products, and recovery of catalysts.

Improved antioxidant activity and delivery of peppermint oil Pickering emulsion stabilized by resveratrol-grafted zein covalent conjugate/quaternary ammonium chitosan nanoparticles

Novel nanoparticles (Z-R/H) were successfully fabricated by a resveratrol-grafted zein covalent conjugate (Z-R) combined with quaternary ammonium chitosan (HTCC), which were used as stabilizers to prepare peppermint oil (PO) Pickering emulsions with antioxidant activity. HTCC effectively adjusted wettability of Z-R conjugate, and three-phase contact angle of Z-R/H3:1 was moderate (95.01°). The influencing factors of Pickering emulsion formation, including volume fraction of PO, concentration of Z-R/H, and mass ratio of Z-R to HTCC, were evaluated by droplet size, ζ-potential, microscopic observation, and stability index analysis. Pickering emulsions stabilized by Z-R/H3:1 showed excellent physical stability under heat treatment. Z-R/H nanoparticles adsorbed on the oil-water interface yielded a dense filling layer as a physical barrier to improve the emulsion stability, which was validated by confocal laser-scanning microscopy. After 4 weeks of storage, retention rate of PO in Pickering emulsion stabilized by Z-R/H3:1 remained high (72.1 %). Electronic nose analysis showed that Z-R/H3:1-stabilized emulsion effectively prevented volatilization of PO aroma components. Additionally, PO and Z-R/H nanoparticles provided an additive antioxidant effect of Pickering emulsions against DPPH and ABTS free radicals. In summary, these novel Z-R/H nanoparticle offer promising applications as a stabilizer with great potential in preparing functional Pickering emulsions to improve essential oil delivery.

Black garlic particles as a natural pigment and emulsifier in a Pickering emulsion based low fat innovative mayonnaise: Improved rheology and bioactivity

Black garlic is rich in brown pigments and Maillard reaction products are known for antioxidant activity and health promoting effects. In the present investigation, we report a facile strategy for fabricating low-fat innovative mayonnaise (IM) using black garlic particles (BGP) as a natural pigment, and a functional ingredient. Whey protein concentrate and high methoxyl pectin at optimized concentrations were utilized for fabricating an IM which served as a control. IM5 and IM10 were ternary composites constituting whey protein, high methoxyl pectin along with BGP (@5 and 10% respectively). The formulation IM10 (BGP @10%) showed high firmness and low spreadability quotient, hence IM5 was taken forward for fabrication for two more variants namely IM-J (using low methoxyl pectin (LMP) from jackfruit peels) and IM-C (LMP from citrus). The effect of BGP and LMP on the functional quality of IM was confirmed through zeta potential, antioxidant activity, textural, rheological, and microscopic evaluation. Fluorescence microscopy confirmed the presence of solid particles over the fat phase of IM, while interaction of pectin and whey proteins was demonstrated through fluorescence emission spectroscopy which clearly displayed stabilization of IM through the formation of Pickering emulsion. Pronounced difference in color and flavor score with BGP established high sensory scores in IM5, IM-J, and IM-C. Rheology supported the stabilizing effects of LMP in IM-J and IM-C in terms of speedy recovery of thixotropy, with recovering storage modulus (G′). Enhanced viscosity of IM-C and IM-J further corroborated the dual effect of LMP and BGP in improving emulsifying and functional quality of IM. Enhanced oxidative stability of IM was established by reduced peroxide and Totox values. Overall our results suggest the promising applications of black garlic as functional ingredient in protein and pectin based Pickering emulsions.

Phase Diagram of Pickering Emulsions Stabilized by Cellulose Nanocrystals.

Cellulose is a promising renewable and biocompatible biopolymer for stabilizing Pickering emulsions (PEs). In the present study, PEs were produced by low-frequency ultrasounds with cellulose nanocrystals (CNCs) and caprylic/capric triglycerides. Phase diagrams allowed to understand mechanisms of formation and long-term stabilization of PEs. Emulsion type, continuous phase viscosity, and yield of oil incorporation were studied after PEs formation. Droplet size, oil release, and stability were measured weekly up to 56 days of storage. Results showed that oil mass fraction above 70% w/w led to unstable W/O PEs. Lower oil mass fraction formed O/W PEs of stability depending on CNC content and oil mass fraction. Droplet size stability increased with CNCs/oil ratio. A very low CNCs/oil ratio led to phase separation and oil release. High CNC content stabilized oil droplets surface, increased aqueous phase viscosity, and prevented creaming. Highly stable PEs were produced for CNC content above 3% (w/w) and oil mass fraction below 50% (w/w). Mechanisms for PEs formation and stabilization were proposed for various CNC contents and oil mass fractions.

Super-amphiphilic graphene promotes peroxymonosulfate-based emulsion catalysis for efficient oil purification.

Oil fractions containing highly toxic and hazardous organic contaminants can not only cause severe environmental disasters, but also an undesired waste of resources. Given the exceptional performance of persulfates in the removal of persistent and refractory organic pollutants from aqueous media, herein, a peroxymonosulfate-based Pickering emulsion catalytic (PPEC) system was constructed for the hazardous oil purification, using super-amphiphilic graphene as a solid emulsifier and a heterogeneous catalyst simultaneously. Combined detailed instrumental analysis with theoretical calculations, we find that the incorporation of pyridinic N and its oxide significantly facilitated the formation of super-amphiphilic graphene and successfully induced the formation of Pickering emulsion. In addition to stabilizing the PPEC system, super-amphiphilic graphene can also achieve efficient removal of Sudan III (simulated lipophilic organic pollutant) by activating peroxymonosulfate (PMS) to generate •O2- and 1O2. Results showed that 80mg/L Sudan III (20mL) could be fully degraded within 30min using 10mL 5mmol PMS. More significantly, our proposed PPEC system also exhibited excellent property in the purification of practical waste engine oil. This study provides new insights into the purification and recovery of waste oil.

Pickering emulsion stabilized by temperature-sensitive PS@PNIPA nanoparticles as microcontainers

Pickering emulsion has attracted the attention of many researchers because of its good stability. In some cases, such as catalyst separation and drug release, control of emulsion stability and demulsification under mild temperature is required. In this work, temperature-sensitive PS@PNIPA (polystyrene@polyisopropylacrylamide) with controlled PNIPA thickness was applied as the Pickering solid emulsifier. The effect of PNIPA thickness on the Pickering emulsion formation was studied by Polarizing optical microscope (POM). PS@PNIPA concentration was also found to be related to the size of the emulsion and the droplet size could be controlled from 17 μm to 39 μm. By changing the temperature, the emulsification/demulsification process of Pickering emulsion is reversible and repeatable for several cycles. Using ibuprofen as a chemical model, the maximum ibuprofen release rate reaches 93% and can be tuned by the temperature. Therefore, this opens up more potential applications for temperature-induced controlled demulsification for chemicals release and related fields.

Interfacial behavior of cyclodextrins at the oil-water interface of Pickering emulsion

An oil-in-water (O/W) Pickering emulsion stabilized by cyclodextrins (CDs), including α-, β-, γ-CD, and the hydroxypropyl (HP) derivatives, was prepared by high-speed homogenization. The interfacial behavior of CDs was studied by the contact angle, surface tension, interface tension, and adsorption kinetics. The physicochemical properties of CD Pickering emulsion were characterized by adsorption content, microstructure, rheology, and instability index. The results showed that the contact angles (85.30° and 75.93°), diffusion rates (−0.2481 and −0.1285), and adsorption rates (−0.0045 and −0.0028) of α-CD and β-CD were significantly higher than those of HP-CD derivatives, and emulsions possessed smaller droplet size (both about 7.5 μm) and better stability compared with HP-CDs derivatives. The formation of Pickering emulsion was attributable to the interfacial adsorption layer structure at the oil-water interface formed by the self-assembly of CD. Subsequent studies on the physiochemical properties of emulsion showed that Pickering emulsions stabilized by α-CD and β-CD had better storage modulus, loss modulus, viscosity, storage stability, and centrifugal stability. HP-α-CD, HP-β-CD, and HP-γ-CD stabilized emulsions delaminated and sedimented within a short time. The amorphous HP-α-CD, HP-β-CD, and HP-γ-CD were difficult to form stable interfacial layers and adsorb on the surface of oil droplets due to their high-water solubility and poor crystallinity. • Interfacial behavior of cyclodextrins in the Pickering emulsion was investigated. • α-CD, β-CD, and γ-CD formed rigid interfacial adsorption layer structure, the emulsions exhibited small droplet size and high apparent viscosity. • HP-α-CD, HP-β-CD, and HP-γ-CD were difficult to form stable interfacial layer, the emulsions exhibited low moduli and poor stability.

Red palm oil Pickering emulsion with pectin yields improved in vitro beta carotene bioaccessibility and oil stability: Physicochemical characterization and shelf stability studies

Pickering emulsion of red palm oil (RPO) with pectin as stabilizer was optimized using response surface methodology (RSM). RSM parameters for final red palm oil pickering emulsion (RPE) were 3% pectin, 30% RPO, and homogenization speed of 24,000 rpm for 15 min. RPE was subjected to physicochemical characterizations, along with storage studies for 15 days. Microstructure imaging of RPE confirmed pickering emulsion formation. Droplet diameter and zeta potential of RPE were 1.779 μm and −32.5 mV, respectively. Fourier transform infrared spectroscopy of RPE suggested hydrogen bonding interactions between the components, and thermogravimetric analysis revealed stability up to 40°C. Gastrointestinal bioaccessibility of naturally occurring β-carotene in the RPE (37.76 ± 1.2%) was found to be four times higher than that of RPO (8.7 ± 0.8%). The RPE was more stable at 4°C as indicated by storage analyses. RPE can improve the bioaccessibility of nutritionally important bioactive compounds. Practical applications Pickering emulsions of RPO stabilized by pectin can be used for developing functional foods with improved bioaccessibility of lipophilic bioactives such as carotenoids as well as for the delivery of temperature sensitive nutritional and bioactive compounds. These emulsions can also be found applications in beverages, low temperature processed foods and vegan fat substitutes.

A first order-based model for the kinetics of formation of Pickering emulsions

Motivation and backgroundMany physical systems are composed of two immiscible fluids containing solid particles whose role is to emulsify the two fluids. Such emulsions are called Pickering emulsions (PE). The present study introduces a theoretical framework for a first order kinetics of the creation of such emulsions and continues to verify the model experimentally using water and oil where water is the majority, or continuous, phase and oil is the minority, or dispersed, phase. These are referred to as O/W emulsions.The motivation for choosing this O/W system is to study the applicability of Pickering emulsions in marine environment and the role these emulsions can play in the cleaning of oil spills. As opposed to the use of surfactants which may be toxic to wildlife, the solid particles used to stabilize PEs are generally non-toxic. Theoretical and experimental methods are employed, as outlined below: Theoretical modelA theoretical model based on first order kinetics is constructed. Unlike classic first order kinetics, our reaction is not chemical nor is it of 1:1 stoichiometry, but its time dependence is similar to that of first order. This behavior is a function of various system-specific parameters such as the energies of the different interfaces in the system, the solid particles’ size, the densities of the components of the system, and the rate at which the system is agitated. The rate of formation of PEs is found to be proportional to 1-e-kt, where t is the time from the moment the system’s components were introduced and k is a constant whose proportionality we describe analytically as a function of the various parameters in the system. Experimental findingsOur experimental results show exceptionally good agreement with the model, and it is shown that for the specific system tested (water, sand, light fraction petroleum), we get full emulsification of the 100ml system with 5 ml petroleum and 50 g sand within about 30s. This result is encouraging for studies that consider the use of such a system for the cleaning of oil spills.

Thermodynamic study on the prevention of B30 biodiesel wax crystallization by γ-Al2O3 nanoparticles and sorbitan monooleate

This paper reports a thermodynamic investigation on the role of γ-Al2O3 nanoparticles and sorbitan monooleate (SMO) as cold-flow improver additives for B30 biodiesel blend. Here, the two additives were able to improve fuel’s cold-flow properties and responsible for reducing wax crystallization temperature as low as 6.42 °C. Based on DCS analysis, the addition of individual SMO or γ-Al2O3 nanoparticles gave rise to the increase in crystallization enthalpy and entropy. However, the opposite effect was observed when they were used in combination. This synergistic effect was found to be responsible for making them effective in the prohibiting the spontaneity of wax crystallization, which was proven by the increase in crystallization Gibbs free energy (ΔGxtal) value from −72.9 to −35.7 J/g. This is primarily due to that the ability of SMO to stabilize wax nuclei and the role of γ-Al2O3 nanoparticles as an additional nucleation site. Furthermore, DLVO analysis also revealed that γ-Al2O3 nanoparticles exhibited high colloidal stability, enabling them to facilitate stable Pickering emulsion formation. Finally, microscopic observations demonstrated that both additives could suppress the formation of insoluble paraffinic “house of cards” crystals.

Synthesis of nanostructured protein-mineral-microcapsules by sonication.

We propose a simple and eco-friendly method for the formation of composite protein-mineral-microcapsules induced by ultrasound treatment. Protein- and nanoparticle-stabilized oil-in-water (O/W) emulsions loaded with different oils are prepared using high-intensity ultrasound. The formation of thin composite mineral proteinaceous shells is realized with various types of nanoparticles, which are pre-modified with Bovine Serum Albumin (BSA) and subsequently characterized by EDX, TGA, zeta potential measurements and Raman spectroscopy. Cryo-SEM and EDX mapping visualizations show the homogeneous distribution of the densely packed nanoparticles in the capsule shell. In contrast to the results reported in our previous paper,1 the shell of those nanostructured composite microcapsules is not cross-linked by the intermolecular disulfide bonds between BSA molecules. Instead, a Pickering-Emulsion formation takes place because of the amphiphilicity-driven spontaneous attachment of the BSA-modified nanoparticles at the oil/water interface. Using colloidal particles for the formation of the shell of the microcapsules, in our case silica, hydroxyapatite and calcium carbonate nanoparticles, is promising for the creation of new functional materials. The nanoparticulate building blocks of the composite shell with different chemical, physical or morphological properties can contribute to additional, sometimes even multiple, features of the resulting capsules. Microcapsules with shells of densely packed nanoparticles could find interesting applications in pharmaceutical science, cosmetics or in food technology.

Interaction between soy protein isolate and surfactant at the interface of antibacterial nanoemulsions loaded with riboflavin tetra butyrate

SummaryRiboflavin tetra butyrate (RTB) is an effective antimicrobial photosensitiser that poses a challenge for long‐term preservation and application due to its hydrophobicity and instability. To overcome this problem, a series of nanoemulsions loaded with photosensitiser RTB was prepared in this study by using soy protein isolate (SPI) as an emulsifier and small molecule surfactant (X) as co‐emulsifier. The interaction mechanism of SPI+X co‐emulsifier and its influence on the stability of emulsion and photosensitiser were explored, and the photodynamic bactericidal effect of the prepared RTB emulsion on S. aureus was studied. SPI and four types of surfactants were present in the form of synergistic (Tween 80, T80) or competition (Span 80, S80 and lecithin, LEC) adsorption or formation of Pickering emulsion (Sodium dodecyl sulphate, SDS) at the oil–water interface. The experimental results revealed that the stable encapsulation ability of RTB emulsions for photosensitisers and their preservation ability can be drastically improved. This work verified that all RTB emulsions could inactive S. aureus under blue light, with an antibacterial ratio of more than 70%. Therefore, the emulsion‐based delivery system effectively improved the water dispersibility and chemical stability of RTB. These results demonstrate that RTB emulsion has the potential to be used as a food‐grade antibacterial emulsion.

Droplet size controllable fabrication of Pickering emulsion stabilized by soy protein isolate-carbon nanotubes/carboxymethyl cellulose sodium

ABSTRACT Pickering emulsion plays an important role in various industrial fields including food, catalysis, and bioscience. Soy protein isolate (SPI) has been proved feasible for stabilizing Pickering emulsion after modification, though such methods were either difficult to proceed or application restrictive. Herein, we report a simple fabrication of oil-in-water Pickering emulsion using a complex of SPI and carbon nanotubes (CNTs)/carboxymethyl cellulose sodium (CMC-Na). The stability of our emulsion could be kept at a wide range of CNTs diameter, oil fraction, and pH, while the emulsion droplet size might be controlled through the tuning of pH and dispersed phase solvent as well. A strong interaction between SPI and CNTs/CMC-Na is a key factor for the homogeneous distribution of CNTs at the aqueous–organic interface, which benefits the Pickering emulsion formation. Our work will offer some useful thoughts for improving the stability of protein-integrated emulsion.

Cyclodextrin-based Pickering emulsions: functional properties and drug delivery applications.

Cyclodextrins (CDs) are biocompatible, cyclic oligosaccharides that are widely used in various industrial applications and have intriguing interfacial science properties. While CD molecules typically have low surface activity, they are capable of stabilizing emulsions by inclusion complexation of oil-phase components at the oil/water interface, which results in Pickering emulsion formation. Such surfactant-free formulations have gained considerable attention in recent years, owing to their enhanced physical stability, improved tolerability, and superior environmental compatibility compared to conventional, surfactant-based emulsions. In this review, we critically describe the latest insights into the molecular mechanisms involved in CD stabilization of Pickering emulsions, including covering practical aspects such as methods to prepare CD-based Pickering emulsions, lipid encapsulation, and relevant stability issues. In addition, the rheological and textural features of CD-based Pickering emulsions are discussed and particular attention is focused on promising examples for drug delivery, cosmetic, and nutraceutical applications. The functionality of currently developed CD-based Pickering emulsions is also summarised, including examples such as antifungal uses, and we close by discussing emerging possibilities to utilize the molecular encapsulation of CD-based emulsions for translational medicine applications in the antiviral and antibacterial spaces.

Organic Hollow Mesoporous Silica as a Promising Sandalwood Essential Oil Carrier.

As film-forming agents, fillers and adsorbents, microplastics are often added to daily personal care products. Because of their chemical stability, they remain in the environment for thousands of years, endangering the safety of the environment and human health. Therefore, it is urgent to find an environmentally friendly substitute for microplastics. Using n-octyltrimethoxysilane (OTMS) and tetraethoxysilane (TEOS) as silicon sources, a novel, environmentally friendly, organic hollow mesoporous silica system is designed with a high loading capacity and excellent adsorption characteristics in this work. In our methodology, sandalwood essential oil (SEO) was successfully loaded into the nanoparticle cavities, and was involved in the formation of Pickering emulsion as well, with a content of up to 40% (w/w). The developed system was a stable carrier for the dispersion of SEO in water. This system can not only overcome the shortcomings of poor water solubility and volatility of sandalwood essential oil, but also act as a microplastic substitute with broad prospects in the cosmetics and personal care industry, laying a foundation for the preparation and applications of high loading capacity microcapsules in aqueous media.

Microfibrillated cellulose from Argania spinosa shells as sustainable solid particles for O/W Pickering emulsions

Microfibrillated cellulose (MFC) from Argan (Argania spinosa) shells was prepared by chemical purification of cellulose, then mechanical disintegration via high pressure homogenization was performed to isolate fibrils of cellulose. Chemical characterization of raw argan shell (AS-R), purified cellulose (AS-C), and argan shell MFC (AS-MFC) included FT-IR, XRD and NMR. Morphological characterization of AS-MFC was assessed using TEM. Next, the use of AS-MFC as oil-in-water (O/W) emulsions stabilizer was investigated. The particle concentration was observed to affect the long-term stability of the emulsions; high concentrations (0.5–1 % w/w) of AS-MFC resulted in emulsions that were thermodynamically stable during 15 days of storage, which was demonstrated by the droplet’s size evolution. The suitable oil concentration for a maximum volume of emulsion using 1 % w/w AS-MFC was demonstrated. The results show that AS-MFC is able to stabilize 70 % w/w MCT oil without visual phase separation. Finally, CLSM shows the adsorption of AS-MFC at the oil-water interface and the formation of a 3D network surrounding oil droplets, confirming Pickering emulsion formation and stabilization.

Pickering emulsions stabilized by sphere-spheroid mixtures

Stable oil-in-water Pickering emulsions (PEs) are prepared by using hydrophilic and oppositely charged spherical (silica) and nonspherical (hematite) nanoparticle mixture. By varying aqueous dispersion pH, the surface potentials of the particles are tuned. For fixed sizes of silica and hematite, stable emulsions are formed at low concentrations of silica when the surface potential mismatch between the particles is high. Conversely, when the latter is small, stable emulsions are found up to high concentration of silica nanoparticles. These findings are explained based on the formation of silica-hematite heteroaggregates and on their surface-active characteristics. It is found that for a given pH and particle concentration (expressed as number ratio NS-H, which is the ratio of the total number of spheres to the total number of spheroids), highly stable oil-in-water emulsions are formed only when the unstable aqueous binary mixture of colloids and the oil phase are emulsified. The result is presented as a state diagram, which shows the particle composition corresponding to the formation of stable emulsions, the composition range where the emulsions that result are unstable and the region where the emulsions do not form at all. As the formation of PE is kinetically controlled, we demonstrate that at conditions where emulsions formed via one-step emulsification for a given NS-H are unstable, following a two-step emulsification procedure yields highly stable emulsions. The work highlights the role of (i) NS-H, (ii) aqueous dispersion pH, (iii) surface potential mismatch and (iv) emulsification protocol on the formation and stability of solid particle stabilized emulsions.

Polyurea/polyaniline hybrid shell microcapsules loaded with isophorone diisocyanate for synergetic self-healing coatings

Polyurea/polyaniline (PU/PANI) hybrid shell microcapsules loaded with isophorone diisocyanate (IPDI) as core material were successfully synthesized by combining Pickering emulsion formation and interfacial polymerization. The self-healing coatings containing 10wt.% IPDI–loaded PU/PANI microcapsules showed a remarkable healing ability and corrosion protection for microcracks after 30 days of immersion in 10wt.% NaCl solution. EIS tests revealed that the impedance modulus of scratched coatings filled with 10wt.% IPDI-loaded PU/PANI hybrid shell microcapsules sustained at 106 Ω·cm2 after 15 days of immersion in 3.5wt.% NaCl solution. The excellent anticorrosion performance was attributed to the effective synergistic effects of both conductive PANI and IPDI healing agent.