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The objective was to study the microstructure, rheology and stability of double (W 1 /O/W 2) emulsions prepared with Tween 80 as hydrophilic emulsifier and coconut, palm or sunflower oil. The effects of glucose concentration in inner aqueous phase and crystallization of lipid phase were analyzed. Aggregation of oil globules by partial coalescence was observed in emulsions prepared with coconut or palm oil because of the crystallization of the lipid phase. The increase of glucose concentration increased the amount of inner water by osmotic swelling and produced a higher partial coalescence degree due to a higher collision frequency between oil globules. Consequently, higher elastic and viscous modules were observed at higher glucose concentration. Fat crystals in lipid phase allowed a partial retention of inner water in the absence of glucose, but they also favored the release of inner water due to partial coalescence. Creaming stability was enhanced by the presence of glucose, because of the formation of a three-dimensional network of aggregated oil globules in emulsions with coconut or palm oil, and a higher packing and global density of oil globules in systems with sunflower oil. The obtained results contribute to the understanding of partial coalescence in W 1 /O/W 2 emulsions, including its effects on inner water release and creaming stability. This work could be relevant for the design and stabilization of vegetable, lipid-reduced food emulsions prepared with natural oils. [Display omitted] • High inner glucose concentration produced osmotic swelling in double emulsions. • The increase of inner glucose concentration increased partial coalescence degree. • Fat crystals prevented complete loss of inner water in the absence of glucose. • A liquid oil phase led to higher inner water content in the presence of glucose. • Partial coalescence and/or higher inner water content enhanced creaming stability. [ABSTRACT FROM AUTHOR]

Droplet microfluidics holds considerable promise across biomedicine, chemistry, and materials science. A comprehensive understanding of the complex dynamics of compound droplets within microchannels is essential for the effective design and optimization of microfluidic devices. This study utilizes computational fluid dynamics to investigate the behavior of compound droplets in straight microchannels, focusing on the effects of varying flow rates of the inner/core, middle, and outer fluids. The Volume of Fluid approach is employed to track the interfaces of different fluids. Results indicate that the flow rate of the outer fluid has a significant impact on flow regime patterns and the breakup of core and shell droplets. A threshold outer fluid capillary number is identified, beyond which the study reveals a transition from compound droplet dripping to single droplet dripping. Pressure signal analysis shows that continuous compound droplet generation requires the middle fluid pressure to exceed that of the outer fluid, while the average pressure of the core fluid should be similar to that of the outer fluid. Additionally, the study explores cases where the core and outer fluids are identical and their interfacial tensions are the same, revealing that increasing the outer flow rate can shift the dripping regime to a jetting regime. These findings offer critical insights for optimizing compound droplet formation in microfluidic systems. [Display omitted] [ABSTRACT FROM AUTHOR]

Antibubbles, characterized by a water-in-air-in-water structure, are a novel dispersion system stabilized by the adsorption of nanoparticles (e.g., silica nanoparticles) at the air-liquid interface and produced via the emulsification-sublimation-rehydration technique. Traditionally, shear-based homogenization has been the standard method for creating Pickering double emulsions, which are then converted into particle-stabilized antibubbles. However, efficient drug delivery using antibubbles requires a small size, narrow size distribution, and high active loading, which are challenges typically faced with shear-based methods. This study introduces the formation of antibubbles using premix membrane emulsification (PME), a gentle technique ideal for heat- and shear-sensitive materials. We conducted a thorough investigation, producing primary and double emulsions with both high-shear homogenization (HSH) and PME through Shirasu porous glass (SPG) membranes. Antibubble size distribution and entrapment efficiency (using a model drug) were analyzed in relation to the process parameters of the emulsification techniques. We found that PME, particularly when using a 30 μm SPG membrane in the secondary emulsification stage, yielded antibubbles with smaller sizes (down to 5 μm in diameter) and significantly higher encapsulation efficiency (up to 80 %) compared to HSH. These findings highlight PME's potential as a superior method for producing nanoparticle-stabilized antibubbles for drug delivery applications. [Display omitted] • Comparison of HSH and PME in producing particle-stabilized antibubbles. • PME yields smaller antibubbles (∼5 µm) with higher encapsulation efficiency. • HSH shows significant entrapment loss during secondary emulsification. • PME is ideal for heat- and shear-sensitive material processing. • Selecting suitable emulsification techniques crucial for uniform antibubble size. [ABSTRACT FROM AUTHOR]

The objective was to study the effect of the variation of Tween 80/sodium caseinate ratio on the microstructure, rheology and freeze-thaw behavior of double (W 1 /O/W 2) emulsions prepared with palm oil. Particularly, the impact of the composition of the outer interfacial film on partial coalescence and retention of inner water droplets was investigated. Partial coalescence was restrained in the emulsion prepared with sodium caseinate only, because aggregation of oil globules was prevented due to electrostatic and steric repulsions and a resistant interfacial film. The inclusion of Tween 80 produced competitive adsorption of emulsifiers, promoting partial coalescence and increasing the elastic and viscous modules of the system. A higher Tween 80 proportion led to lower retention of inner water droplets after cold storage, attributed to the formation of smaller oil globules and a thinner interfacial film. A cooling-heating-cooling cycle was applied by differential scanning calorimetry, showing that a higher oil globule aggregation degree led to higher retention of inner water droplets during freezing and higher release of inner water droplets during thawing. The findings expand the knowledge regarding the influence of the composition of the outer interfacial film on both partial coalescence and retention of inner water droplets in W 1 /O/W 2 emulsions. [Display omitted] ● Partial coalescence in W 1 /O/W 2 emulsions is promoted by the presence of Tween 80. ● Higher Tween 80/sodium caseinate ratio led to lower encapsulation efficiency. ● Oil globule aggregation favors retention of inner water droplets during freezing. ● Oil globule aggregation favors release of inner water droplets during thawing. [ABSTRACT FROM AUTHOR]

Due to their multicomponent structure, water-in-oil-in-water (WOW) double emulsions are of great interest for the encapsulation of hydrophilic substances. Although promising applications are reported, few double emulsion products are available on the market because their stabilization is still challenging. To stabilize all internal interfaces, at least two interfacial active substances (IAS), a lipophilic and a hydrophilic one, have to be added. These IAS can interact with each other at the interfaces and thus might impair the double emulsion stability. Especially the impact of these interactions on the loss of inner water droplets due to coalescence with the outer water phase is largely unknown. In this study, we investigated if interfacial tension measurements can be related to the loss of inner water caused by coalescence. We determined the outer oil in water interfacial tension of a double emulsion, when a hydrophilic or a lipophilic IAS is used individually as well as in combination. Furthermore, the coalescence process between a water droplet encapsulated in oil and an adjacent continuous water phase was observed in single droplet experiments. As model system polyvinyl-alcohol (PVOH) was used as hydrophilic and polyglycerol-polyricinoleate (PGPR) was used as lipophilic IAS. For the sole use of PVOH, the behavior of the coalescence process can be related to the interfacial tension, which was changed by varying the PVOH type. It could be shown that the lower the interfacial tension is, the longer is the time until the coalescence process takes place. In addition, the duration of the coalescence process itself increases by decreasing the interfacial tension for the system under study. In case of the combined use of PVOH and PGPR, the observations differ in dependency on the PVOH type. In case of PVOH with a low hydrophobicity, the simultaneous presence of PGPR caused only a minor change of the coalescence behavior compared to the sole use of PVOH. In case of a PVOH type with higher hydrophobicity, the coalescence behavior changed clearly by the presence of PGPR. However, no correlation to the interfacial tension was found. [ABSTRACT FROM AUTHOR]

Water in oil in water (WOW) double emulsions have a great potential as encapsulation systems in different industrial sections. Nevertheless, there are only few double emulsion based products available on market. An important limitation, regarding the product launch, is the insufficient stability of these products. Many instability mechanisms have to be taken into account: coalescence between inner water droplets, coalescence between outer oil droplets, coalescence between inner and outer water phase, and diffusion between the dispersed water droplets and the continuous outer water phase. In the present study, we focus on structural changes and stabilization mechanisms of inner water in oil (WO) emulsions. Osmotic active substances (OAS) have to be used in the inner water droplets to limit the diffusion processes between the water phases in double emulsions. We therefore investigated the influence of different OAS on the structural changes in WO emulsions. We focused on three subprocesses influencing the emulsification result: droplet breakup, stabilization directly after breakup and diffusional processes after droplet stabilization. For this, we prepared WO emulsions using sodium chloride, calcium chloride and glucose as OAS and polyglycerine-polyricinoleate as lipophilic emulsifier. The droplet size distribution was determined to evaluate structural changes. Furthermore, we measured interfacial properties and emulsion viscosities to evaluate stabilizing effects. Kinetic stabilization effects were evaluated by applying high pressure homogenization, known as a process with high requirements on the stabilization efficiency. The osmolality of the inner water phases was determined as parameter for the likelihood of diffusional processes. This characteristic value strongly depends on OAS type and concentration. Adsorption kinetics and diffusional processes turned out as the main factors influencing inner emulsion structure. [ABSTRACT FROM AUTHOR]

Due to their multicomponent structure, double emulsions are of great interest for different industrial areas. Nevertheless, there are only a few products on the market. Due to the enforced use of different stabilizing agents, production and stabilization of the double emulsions remains challenging. The stabilizing agents can interact with each other, which might cause a change of interfacial properties and emulsion structure. To gain a deeper understanding of occurring interactions at the oil water interface, interfacial properties were measured using the pendant and oscillating drop technique. The preparation and characterization of single oil in water emulsions containing all stabilizing agents of double emulsions enables the direct correlation between interfacial properties and emulsion structure. For the interfacial and emulsification experiments, polyvinyl-alcohol (PVOH) with varying molecular weight and degree of hydrolysis, polyglycerol-polyricinoleate (PGPR) and sodium chloride (NaCl) were added step-by-step. Furthermore, stability to coalescence in emulsifying processes was evaluated using different devices: a colloid mill (CM) and high-pressure homogenization (HPH). High molecular weight PVOHs interacted with PGPR at the interface but this did not influence the emulsion structure neither for efficient (HPH) or gentle (CM) droplet disruption processes. The low molecular weight PVOH of slight hydrophobic character interacted with PGPR at the interface and this lead to the breakage of the emulsions. At increased hydrophobicity of PVOH, no change in interfacial activity and no change in emulsion structure was found for the low molecular weight PVOH. Based on these findings it is recommended to use high molecular weight emulsifiers to stabilize the outer emulsion of double emulsions. Thereby, it is not necessary to select emulsifiers with a well defined interfacial activity. However, the viscosity of the product is high in this case. If a low product viscosity is required, the hydrophilic emulsifier has to be selected carefully due to a specific interfacial activity. [ABSTRACT FROM AUTHOR]

It was shown recently that a solid-to-solid phase transitions (α-to-β, gel-to-crystal), typical for many lipid substances, can lead to formation of nanoporous network inside lipid micro-particles dispersed in aqueous surfactant solutions (Cholakova et al. ACS Nano 2020 , 14, 8594). These nanopores are spontaneously infused by the aqueous phase when appropriate combination of water-soluble and oil-soluble surfactants is applied. As a result, the initial lipid micro-particles can spontaneously burst into much smaller nanoparticles, just by cooling and heating of the initial dispersion. Under certain conditions, the infused aqueous phase is entrapped in the moment of lipid particle melting and double emulsion of type water-in-oil-in-water (W/O/W) is formed. The current study aims to clarify how the composition of the lipid micro-drops and surfactants affect the observed phenomena. Selected mixtures of monoacid triglycerides are studied systematically. The results show that the bursting efficiency usually decreases when the complexity of the lipid mixture increases, due to the expanded temperature interval for lipid melting. Nevertheless, complete particle bursting and lipid nanoparticles with diameters down to 20 nm are formed even for the most complex lipid compositions under appropriate conditions. The key mechanisms leading to efficient fragmentation and double emulsion formation are clarified, and the main governing factors are explored. On this basis, we reveal that the system behavior can be switched between complete particle bursting and W/O/W emulsion formation by: (1) Change in the cooling and heating rates without any changes in the chemical composition, (2) Change in the concentration of oil-soluble surfactant, and/or (3) Change in the phase in which the oil-soluble surfactant is introduced initially. Thus, we have formulated guiding rules to control the formation of lipid nanoparticles and W/O/W emulsions with triglyceride mixtures promising multiple potential applications. [Display omitted] [ABSTRACT FROM AUTHOR]

The use of biopolymers as hydrophilic emulsifiers in water-in-oil-in-water double emulsions is often proposed in literature [1,2] . They are supposed to not diffuse from one water phase into the other one and thus being better suitable for the stabilization of W/O/W emulsions than short-chain hydrophilic emulsifiers. We compare different biopolymers as emulsifiers and stabilizers for food grade W/O/W emulsions. Egg yolk and whey protein isolate (WPI) were used as typical emulsifiers in foods. Pectin, gum arabic and carboxy methylcellulose (CMC) were chosen as typical food stabilizers. For comparability, we produced double emulsions of different oil drop size. Encapsulation efficiency was measured by a DSC method that allows for direct determination of the amount of encapsulated water. The relationship between encapsulation efficiency and oil drop size was independent of emulsifier concentration when using egg yolk. In contrary, the encapsulation efficiency of WPI-stabilized emulsions decreased with increasing concentration. Moreover, a stabilization of W/O/W emulsions is possible by exclusively using selected stabilizers in the outer water phase. Highest encapsulation efficiencies were found for CMC-stabilized double emulsions. Measurement of interfacial tensions revealed that this stabilizer has the lowest interfacial activity. These results indicate that using a biopolymer does not guarantee for double emulsion stability. [ABSTRACT FROM AUTHOR]

We compare different emulsification devices for the production of W/O/W double emulsions. Rotor-stator devices (colloid mill and tooth rim dispersing machine), high pressure homogenization (standard and modified process) as well as a rotating membrane system were used. For better comparability, we produce double emulsions of different oil drop sizes with each device by changing process parameters. A standard double emulsion recipe was chosen for all emulsions. Encapsulation efficiency of water in the double emulsions, measured by DSC technique, is found to be directly dependent on oil drop size of the double emulsions for each emulsification device. The bigger the oil drops, the higher is the encapsulation efficiency. Double emulsions with comparable oil drop sizes produced with different devices show more or less the same encapsulation efficiency. This finding indicates that coalescence is mainly influenced by geometrical parameters like oil drop size. The differing drop breakup mechanisms in the different emulsification devices do not show any influence on encapsulation efficiency. It can thus be concluded that loss of inner water droplets by coalescence mainly takes place after the production process. The choice of the emulsification device does not directly influence encapsulation efficiency. Conventional high shear devices are as suitable for the production of double emulsions as membrane processes. [ABSTRACT FROM AUTHOR]

We investigate deformation and breakup of double emulsion drops, in a system consisting of an aqueous continuous phase and double emulsion oil drops containing smaller droplets of water. The system is stabilized by the presence of the surfactant polyglycerol polyricinoleate (PGPR). Extensional flow generated in a 4-roll mill is used for these investigations. Steady state deformation is not influenced by the concentration of the innermost water droplets, and thus, in the range of strain rates studied, is not affected by the rheological properties of the drop phase. Moreover, drop shapes and relaxation behavior also do not depend on the disperse phase concentration of the water droplets. Finally, the critical Capillary number for drop breakup is independent of viscosity ratio. These observations seem to be at least partly the result of immobilized drop interfaces under the flow conditions that were studied. An important phenomenon is loss of the innermost water droplets by coalescence with the outer water phase. This is only observed in this system if a hydrophilic surfactant is dissolved in the continuous phase. Moreover, if coalescence occurs, coalescence phenomena are observed to be independent of the deformation and breakup of the double emulsion drop. Coalescence phenomena do not only take place within seconds but can be observed over several minutes. This implies that instabilities in multiple emulsions are not mainly governed by process conditions, but are rather an intrinsic consequence of the formulation. [ABSTRACT FROM AUTHOR]

O/W/O double emulsions are studied by means of 1 H nuclear magnetic resonance (NMR) and confocal laser scanning microscopy (CLSM) with respect to their structural and diffusion properties. Due to the structure of double emulsions, common droplet sizing techniques such as laser scattering methods show limited applicability, especially with respect to the inner droplet size distribution and dynamic effects on the molecular level. However, geometrical and structural information can be extracted from pulsed field gradient stimulated echo (PFG-STE) NMR measurements, as the molecules in the different phases experience hindered and restricted diffusion due to the interfaces. Additionally, the permeability of the interfaces and the diffusion across the intermediate (hetero) phase can be observed either by PFG-STE NMR or by exploiting the possibilities of paramagnetic relaxation enhancement. The NMR results are confirmed by CLSM with respect to both the droplet size distribution and the exchange of molecules in this publication especially for the O/W/O type of double emulsions. [ABSTRACT FROM AUTHOR]

Highlights: [•] Formulation of polymeric particles through double emulsion like process. [•] Effects of process parameters on particles colloidal properties. [•] Both agitation time and speed affect the final average particles size. [•] The use of high amount of polycaprolactone leads to large particles size. [ABSTRACT FROM AUTHOR]

The low solubility of quercetin considerably decreases its loading efficiency in traditional water and oil-based emulsion systems, which has limited their applications. To find a solution to this issue, in this investigation, polyol consisting of dipropylene glycol and glycerol as a solvent was used to increase quercetin solubility. It was further incorporated in polyol-in-oil-in-water Pickering double emulsions stabilized by SiO 2. The characterization of these Pickering double emulsions was performed by analyses of their microscopic structures, particle sizes, rheology, and storage stability. The rise in the concentration of quercetin from 0 to 0.60 wt% decreased the droplet size of these emulsions and increased their viscoelasticity and storage stability. The microstructure of the emulsions showed the presence of some quercetin on the water-oil interface, suggesting that this bioactive compound might have recrystallized from the internal polyol phase during the preparation and then acted as a particle stabilizer in synergy with SiO 2. To test and validate this hypothesis, we examined the Pickering stabilization properties of the recrystallization quercetin and its interaction with SiO 2. We found that the recrystallized quercetin interacted with SiO 2 through a hydrogen bond and co-stabilized the interface. Additionally, it also served as a thickener that was involved in the development of an intense entangled network structure that connected the droplets, which improved the emulsion stability. These results revealed an effective approach for the preparation of stable Pickering double emulsions with high quercetin loading. [Display omitted] [ABSTRACT FROM AUTHOR]

Highlights: [•] Uniform micrometer-sized porous polymer particles with closed-cell pores. [•] Particle size control: limited coalescence of a Pickering (W1/O/W2) double emulsion. [•] Use of ionized hydrocolloid in W1 for colloidal stability of W1/O. [•] High pressure homogenization of double emulsion without losing W1 features. [•] Control of osmotic pressure in W1 and W2 to tailor size of pores and porosity. [Copyright &y& Elsevier]

Abstract: Here, a well-controlled method to prepare magnetic/cisplatin-loaded nanocapsules with different morphologies has been developed by using a W/O/W double emulsion-solvent evaporation technique. This study focuses on the influences of solvent removal method and existence of stabilizers on the characteristics of nanocapsules in a double emulsion procedure. Biodegradable poly(lactic-co-glycolic acid) [PLGA] nanocapsules were used for encapsulation of cisplatin and magnetic nanoparticles. The effect of preparation conditions on the size, morphology and surface properties of PLGA nanocapsules containing cisplatin and magnetic nanoparticle were investigated too. Solvent removal from the double emulsion was carried out by using two methods; slow evaporation at ambient condition and fast evaporation under reduced pressure. PLGA nanocapsules were prepared in the presence of stabilizers during the first and second emulsification steps and also without any stabilizer. Changing in the morphology and decrease in mean diameter of magnetic nanocapsules were observed when slow evaporation was exploited in comparison with evaporation at reduced pressure. It was found that the loading efficiency of cisplatin was dramatically dependent on the solvent removal method. This step had a significant effect on morphology and size. DLS data showed that the mean diameter of magnetic nanocapsules was ranging between 142 and 384nm with polydispersity index of 0.071–0.111 with zeta potential from −10.5 to−16.5mV. On the other hand, the loading efficiency of cisplatin was related to the preparation conditions and was between 41 and 62% (w/w). The prepared nanocapsules were characterized by SEM and AFM to observe surface topography. These micrographs reveal a spherical shape of magnetic nanocapsules with smooth surface and almost no aggregation was observed. TEM analysis was used to investigate the internal morphology of magnetic/cisplatin-loaded nanocapsules, too. [Copyright &y& Elsevier]

Abstract: The objective of this study was to investigate the influence of acylglycerol (AG; mono-diglycerides) and acylpropyleneglycol (APG; fatty acid mono-diesters of propylene glycol) lipophilic emulsifiers, as well as their mixtures, on the structural transformations of emulsions, observed during emulsion formation and storage. The investigations aimed to characterize the phenomena that can be encountered during the manufacturing and shelf-life of emulsions prepared with these commonly used emulsifiers. It was found that in the presence of AG or AG–APG mixtures and up to 55–60wt.% water content (depending on the emulsifiers proportions) continuous emulsification and cooling of the water-in-oil (W/O) emulsion initially formed, led to the local phase inversion and finally formation of an oil-in-water-in-oil (O/W/O) double emulsion with unique structure. The inversion was caused by the temperature-dependent formation of the multilamellar liquid-crystalline structures of monoglyceride in the aqueous phase of emulsion. The self-assembled structures encapsulated oil droplets formed under the dynamic emulsification conditions and immobilized them in a liquid-crystalline gel matrix. The resulting oil-in-water (O/W) emulsion gel was then gradually dispersed in the oil phase, which was not involved in the formation of the internal oil droplets. Finally, double O/W/O-type droplets were produced. Their structure can be described as an O/W-emulsion lamellar-gel core surrounded by the interfacial layer of the crystallized surface-active components of the emulsifiers. Such droplets coexisted in the external oil phase with water droplets. When APG emulsifier was used as a sole stabilizer, no phase inversion was observed. The W/O emulsion produced with this emulsifier underwent crystallization- and shear-induced flocculation and subsequent deflocculation during the emulsification. We also report on the time-dependent structural evolutions of the finally produced emulsions. The outcome of the multiple light scattering experiments and microscopic observations was that emulsions based on the AG emulsifier or the AG-rich AG–APG blends developed with time towards more tightly packed systems due to formation of a fat-crystal network in the continuous oil phase. When the only emulsifier used was APG, the structure of emulsion settled within three weeks, due to formation of crystalline bridges between droplets. [Copyright &y& Elsevier]

Abstract: The activated form of N-glutaryl-phosphatidylethanolamine (aNGPE) has been incorporated into water-in-oil-in-water (W1/O/W2) double-emulsion globules. Preparation of individual globules within a cylindrical capillary and video microscopy of their behavior enabled determination of the rate of coalescence of internal aqueous droplets (W1) with the external aqueous phase (W2), termed external coalescence. The presence of Tween 80 in the external phase at concentrations of 0.01 and 0.012M effected such coalescence. The concentration of Span 80 in the oil phase exceeded that of aNGPE considerably, with the ratio of Span 80 to aNGPE molecules ranging from 60 to 1363. Despite the low relative concentration of aNGPE, external coalescence of the internal droplets was prolonged in globules containing this cosurfactant as compared to globules containing only Span 80. Increasing the amount of phospholipid in the oil phase did not significantly affect the rate of release, indicating that within our range of concentrations (22.0–91.3μM) there was little variation in the amount of phospholipid adsorbing at the interface. These results indicate that, in addition to its suitable protein-binding functionality, aNGPE can prolong the release of internal droplets in a W1/O/W2 globule; its use as a cosurfactant shows potential benefits for drug-delivery applications. [Copyright &y& Elsevier]

Microfluidic technology has provided the possibility of double and multi-layered emulsion generation consisting of layers to project the core material which has several biomedical and industrial applications. However, limited numerical analysis and geometrical factors, as a powerful means of performance enhancement, are conducted in this literature. In this study, parametric research about the effects of characteristic design parameters on droplet generation by using Lattice Boltzmann Method is presented. In this regard, a new one-step model based on the co-flowing concept is designed and the influential geometrical factors are determined. Furthermore, each factor is optimized individually and a better outlook for further research and manufacturing is provided. The results are reported in terms of drop and droplet size, shell thickness and separations points. Consequently, for a specific purpose, the desired design parameters can be selected to increase the droplet generation performance. [Display omitted] • A novel microfluidic device design for double emulsion formation is presented. • A parametric study of geometrical factors of drop and droplet generation is conducted. • Double co-flowing concept is applied and the performance of device is optimized. • Depending on specific double emulsion production purposes, efficient geometrical values are reported. [ABSTRACT FROM AUTHOR]

• Matrix microcapsules elaboration from double fragrance-in-aqueous phase-in perfumery solvent emulsion. • Polymerization and cross-linking of the intermediate aqueous phase. • Modularity of fragrance release from microcapsules thanks to the choice of the cross-linker. • Model fragrance composed of a blend of 13 molecules current in perfumery. This paper describes a new route to synthesize polymeric capsules with interesting and diverse diffusive and mechanical properties. Such capsules were obtained by free radical cross-linking copolymerization of the intermediate water phase of a double oil-in-water-in-oil (O/W/O) emulsion. Such a strategy allows separating the locus of polymerization from the fragrance- containing compartment. Indeed fragrance molecules are known to be reactive. The encapsulated species, also corresponding to the innermost oil, was a model fragrance composed of more than 10 various molecules usually used in perfumery. In a first step, the double emulsion containing a hydrophilic monomer, either Methacrylamide or Oligo(ethyleneglycol) methacrylate, and a hydrophilic cross-linker, either Tetra(ethyleneglycol) diacrylate or N,N-Methylene-bis-Acrylamide, was formulated. The influence of the cross-linker agent on the feasibility of the double emulsion was examined. Then, in a second part, the polymerization was performed. Four different systems of capsules were developed and compared in terms of diffusive and mechanical properties. We show that changing the monomer /cross-linker couple allowed modulating the capsule properties. [ABSTRACT FROM AUTHOR]