Simple Emulsion Research Articles

Formation development and evaluation of microsphere of sulfasalazine for the treatment inflammatory bowel diseases

Inflammatory bowel disease (IBD) is a chronic relapsing and remitting inflammatory disorder of the small intestine and colon. IBD includes ulcerative colitis (UC) and Crohn’s disease (CD), and it is a main reason for the expansion of colon cancer, referred to as colitis-associated cancer (CAC). Oral colon-targeted microsphere based drug delivery system containing sulfasalazine was prepared, optimized and characterized. The microspheres were effectively prepared by simple emulsification phase-separation technique followed by cross-linking. The formulations were optimized on the basis of drug: polymer ratio, stirring speed, concentration of glutaraldehyde. The prepared microspheres were characterized on the basis of morphology, entrapment efficiency, particle size and in-vitro release.
 Keywords: Microspheres, Sulfasalazine, Inflammatory bowel disease, Colon-targeted, Chitosan

Double (W1/O/W2) and Simple (O/W2) Emulsions Prepared with Soybean Flour Dispersion and Vegetable Fat: Partial Coalescence Promotion by Polyglycerol Polyricinoleate and Calcium

AbstractThe objective is to study the partial coalescence process in calcium‐fortified double (W1/O/W2) and simple (O/W2) emulsions prepared with soybean flour dispersion as continuous aqueous (W2) phase and vegetable fat plus polyglycerol polyricinoleate (PGPR) as lipophilic emulsifier (at varied concentration) in lipid phase. Calcium chloride is included in the dispersed aqueous (W1) phase and the W2 phase of W1/O/W2 and O/W2 emulsions, respectively. No partial coalescence is observed in the O/W2 emulsion without PGPR and calcium, while the inclusion of the emulsifier and/or divalent cation promotes the phenomenon. The presence of PGPR in lipid phase or calcium in W2 phase can enhance capture efficiency because of the decrease of electrostatic and steric repulsions between fat globules, the modification of fat crystals, and/or the increased size of individual globules. W1/O/W2 emulsions show a lower partial coalescence degree in comparison to O/W2 emulsions prepared with the same components, attributed to the isolation of a fraction of added calcium in the W1 phase of the former systems. PGPR produces microstructural and rheological changes over time in emulsions subjected to prolonged cold storage; but its effect is reduced in the presence of calcium, probably because of the formation of stronger globule aggregates.Practical applications: This article deals with two parallel phenomena occurring in W1/O/W2 and O/W2 emulsions prepared with soybean flour dispersion as W2 phase and vegetable fat in lipid phase: the promotion of partial coalescence by the lipophilic emulsifier, PGPR; and the aggregation of proteins and fat globules due to the presence of calcium in W2 phase. In this way, the effects of PGPR and/or calcium on partial coalescence are studied in these systems, analyzing their microstructure and rheology. The encapsulation of calcium within the W1 phase of W1/O/W2 emulsions and its impact on partial coalescence is also analyzed. The results obtained in this work can be relevant for the formulation of calcium‐fortified, vegetable food emulsions, showing a texture similar to whipped dairy cream, where PGPR concentration or calcium release can be controlled to adjust the rheological characteristics of the system.

Micro-dispersed essential oils loaded gelatin hydrogels with antibacterial activity

Plant-based essential oils (EOs) are natural antimicrobial agents that have a relatively new application as edible coatings to extend the shelf life of foods such as meat. In this study, we developed gelatin hydrogels containing microdroplets of rosemary essential oil (REO) and orange essential oil (OEO). The microdroplets were successfully stabilized by the surfactant Tween®80. The droplet size distribution was slightly affected by the type of EO and homogenization time. The rheological properties in the linear viscoelastic range depend on the EO concentration and the Bloom number of the gelatin. The nonlinear behavior remains typical of gelatin gels, with stiffening and shear thickening at large deformation amplitudes. Escherichia coli and Bacillus cereus were sensitive to the gelatin-REO hydrogels with a minimum inhibitory concentration (MIC) of 0.5%. The gelatin-OEO hydrogels inhibited only Bacillus cereus with an MIC of 0.5%, but the gelatin-REO hydrogels showed greater cell reduction. Surprisingly, the Staphylococcus aureus strain used here was resistant to all gelatin-EO hydrogels. Our experiments show that gelatin-EO hydrogels prepared by simple emulsification have high stability and antibacterial activity suitable for potential preservation of gelatin-tolerant foods.

One‐Step Preparation of All‐Natural Pickering Double Emulsions Stabilized by Oppositely Charged Biopolymer Particles

AbstractDouble emulsions are complex fluid systems, which offer significant advantages over simple single emulsions for encapsulation, protection, and sustained release of cargos. However, they are thermodynamically unstable systems. Double emulsions are usually prepared using two sets of surfactants with different hydrophilic–lipophilic balance values. However, these surfactants often interfere with each other, thus affecting the emulsion stability. Colloidal particles have also been used to prepare double emulsions, which are known as Pickering double emulsions. The formulated double system is, however, temporary, and the adjustment of particle wettability is cumbersome and expensive. Here, the authors report a one‐step emulsification process to generate water‐in‐oil‐in‐water double emulsions using two oppositely charged, plant‐derived particles, zein nanoparticles, and cellulose nanocrystals as stabilizers. The stabilization is attributed to the adsorption of aggregates formed by the two types of particles through electrostatic attraction at the oil–water interface with different curvatures. The application of co‐encapsulation of β‐carotene and epigallocatechin gallate is demonstrated, which synergistically improves their stability under different conditions. Therefore, the formulated all‐natural Pickering double emulsions can find applications in various industries, including food, pharmaceutics, and cosmetics.

Building carbazole-decorated styrene–acrylic copolymer latexes and films for iron(III) ion detection

The detection and sensing of trace iron(III) ions is a crucial but challenging task. Herein, we report a facile strategy to build carbazole-based copolymer latexes and films via semi-continuous emulsion copolymerization for the selective detection of iron(III) ions. Carbazole-decorated styrene–acrylic copolymer latexes were synthesized by the copolymerization of styrene, acrylates, and N-vinylcarbazole (NVCz) under mild conditions. The effects of the comonomer composition on emulsion copolymerization and the properties of the copolymer latexes/films were studied. The obtained copolymer latexes exhibit homogeneous spheres through regulating the NVCz content from 0 to 5 wt%. Notably, the copolymers exhibited the characteristic emission of carbazole in both latex and solution form, and the emission intensity can be easily tuned by varying the NVCz content. Surprisingly, higher carbazole content led to differences in the excitation and emission peaks of the latex and solution, resulting from the formation of an excimer in the latex. Moreover, the fluorescence of the latex and film can be selectively and effectively quenched by trace amounts of iron(III) ions in aqueous media. The limits of detection (LODs) of the copolymer latex and film were 1.90 and 1.71 μM, respectively. These results illustrate that the carbazole-decorated styrene–acrylic copolymer prepared employing a facile, inexpensive, scalable and environment-friendly procedure can be used to fabricate high-performance photoelectric devices and high-efficiency fluorescent sensors. Carbazole-decorated styrene–acrylic copolymer latexes were prepared by simple and environment-friendly emulsion polymerization. The obtained copolymer exhibit characteristic emission of carbazole in both latex and solution, and their emission intensity can be well tuned by varying NVCz content and selectively quenched by trace amounts of Fe 3+ . • Preparation of carbazole-decorated styrene-acrylic copolymer via emulsion polymerization. • Regulation of the emission intensity through varying N-vinylcarbazole content. • Application of the prepared copolymer latexes/films for fluorescence sensing. • Selective Fe 3+ ions detection via fluorescence quenching.

Droplet Microfluidics for Food and Nutrition Applications.

Droplet microfluidics revolutionizes the way experiments and analyses are conducted in many fields of science, based on decades of basic research. Applied sciences are also impacted, opening new perspectives on how we look at complex matter. In particular, food and nutritional sciences still have many research questions unsolved, and conventional laboratory methods are not always suitable to answer them. In this review, we present how microfluidics have been used in these fields to produce and investigate various droplet-based systems, namely simple and double emulsions, microgels, microparticles, and microcapsules with food-grade compositions. We show that droplet microfluidic devices enable unprecedented control over their production and properties, and can be integrated in lab-on-chip platforms for in situ and time-resolved analyses. This approach is illustrated for on-chip measurements of droplet interfacial properties, droplet–droplet coalescence, phase behavior of biopolymer mixtures, and reaction kinetics related to food digestion and nutrient absorption. As a perspective, we present promising developments in the adjacent fields of biochemistry and microbiology, as well as advanced microfluidics–analytical instrument coupling, all of which could be applied to solve research questions at the interface of food and nutritional sciences.

Biocompatible Polymer and Protein Microspheres with Inverse Photonic Glass Structure for Random Micro‐Biolasers

The miniaturization of random lasers to the micrometer scale is challenging but fundamental for the integration of lasers with photonic integrated circuits and biological tissues. Herein, it is demonstrated that random lasers with a diameter from 30 to 160 μm can be achieved by using a simple emulsion process and selective chemical etching. These tiny random laser sources are made of either dye‐doped polyvinyl alcohol (PVA) or bovine serum albumin (BSA) and they are in the form of microporous spheres with monodisperse pores of 1.28 μm in diameter. Clear lasing action is observed when the microporous spheres are optically excited with powers larger than the lasing threshold, which is 154 μJ mm−2 for a 75 μm diameter PVA microporous sphere. The lasing wavelength redshifts 10 nm when the PVA microsphere diameter increases from 34 to 160 μm. For BSA microspheres, the lasing threshold is around 55 μJ mm−2 for a 70 μm diameter sphere and 104 μJ mm−2 for a 35 μm diameter sphere. The simple fabrication process reported allows for detail studies of morphology and size, important for fundamental studies of light–matter interaction in complex media, and applications in photonic integrated circuits, photonic barcoding, and optical biosensing.

Quality by Design Approach for Formulation and Optimization of Microparticles Based Inhalable Phytopharmaceuticals of Trigonella Foenum-Graecum and Alpinia Galanga

Chronic obstructive pulmonary disease has been the most widespread worldwide health problem that has influenced millions of people worldwide. The freeze-dried inhalable microparticles (FDIMs) of Trigonella foenum-graecum and Alpinia galanga extracts were synthesized by simple emulsification solvent evaporation technique using polyvinyl pyrrolidone K30 (PVP K30) and polyethylene glycol 6000 (PEG 6000) and were optimized using Box-Behnken design (BBD). Mannitol was utilized for surface modification of FDIM for enhancing their aerodynamic characteristics. The independent parameters which were utilized in the optimization strategy were herbal extract: polymer (w/w, X1), mannitol (% w/v, X2), and surfactant (% v/v, X3). The studied response variables were mean diameter (µm) (Y1) and bulk density (g/cc) (Y2). The present study concluded that optimized FDIMs could be successfully manufactured using herbal extract: polymer (1:2 w/w), mannitol (4.616 % w/v) and surfactant (1.5 % v/v), which had 0.977 desirability functions. The predicted values of response parameters of optimized FDIMs were found at 1.326 µm mean diameter and 0.244 g/cc bulk density. The percentage relative error between actual and model-predicted values of mean diameter and bulk density for optimized FDIM was found 4.09 and 2.45%, respectively (< 5%), which authenticated the articulacy of the optimization approach.

Evaluation of viability of encapsulated Lactobacillus rhamnosus GG and Lactobacillus plantarum in multilayer emulsion and simple emulsion

Evaluation of viability of encapsulated Lactobacillus rhamnosus GG and Lactobacillus plantarum in multilayer emulsion and simple emulsion

Self-assembly in soft matter with multiple length scales

Spontaneous self-assembly in molecular systems is a fundamental route to both biological and engineered soft matter. Simple micellization, emulsion formation, and polymer mixing are well understood. However, the principles behind emergence of structures with competing length scales in soft matter systems remain unknown. Examples include droplet-inside-droplet assembly in many biomacromolecular systems undergoing liquid-liquid phase separation, analogous multiple emulsion formation in oil-surfactant-water formulations, and polymer core-shell particles with internal structure. We develop here a microscopic theoretical model based on effective interactions between the constituents of a soft matter system to explain self-organization both at single and multiple length scales. The model identifies how spatial ordering at multiple length scales emerges due to competing interactions between the system components, e.g., molecules of different sizes and different chemical properties. As an example of single and multiple length scale assembly, we map out a generic phase diagram for a solution with two solute species differing in their mutual and solvent interactions. We further connect the phase diagram to a molecular system via molecular simulations of a block-copolymer system that has a transition from regular single-core polymer particles to multicore aggregates that exhibit multiple structural length scales. The findings provide guidelines to understanding the length scales rising spontaneously in biological self-assembly but also open venues to the development and engineering of biomolecular and polymeric functional materials and pharmaceutical formulations.Received 20 January 2021Accepted 25 March 2021DOI:https://doi.org/10.1103/PhysRevResearch.3.L022008Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasClassical statistical mechanicsClusteringPhase diagramsSelf-assemblyThermodynamicsCondensed Matter, Materials & Applied PhysicsStatistical PhysicsPolymers & Soft Matter

Fluorescent CdSe/ZnS quantum dots incorporated poly (styrene-co-maleic anhydride) nanospheres for high-sensitive C-reaction protein detection

We have reported the formation of fluorescent CdSe/ZnS quantum dots (QDs) incorporated poly (styrene-co-maleic anhydride) spheres in nanoscale range with a simple emulsification solvent evaporation strategy. The influence parameters on the size and internal structure of the composite nanospheres, such as copolmer/QDs mass ratio and volume ratio of water/chloroform were systematically investigated. Our obtained QDs incorporated polymer nanospheres were suitable for some immunoassays which strongly required nano-sized fluorescent labels, such as lateral flow immunoassays (LFIAs), in which “easily flowing chromatographically along the strip” was needed. Finally, carboxyl-functionalized nanospheres were used as fluorescent tags and imported into LFIA system to on-site high-sensitively assess the level of C-reaction protein (CRP). Within the range of high-sensitive detection (from 0.04 to 10.0 mg/L), nanosphere-based LFIA sensor exhibited linear detection of CRP (R2 = 0.9995) and a detection limit of 0.04 mg/L, which may be useful to improve the risk assessment of cardiovascular disease.

Short-term ingestion and tissue incorporation of Polystyrene microplastic in the scleractinian coral Porites porites

Microplastics (MP), plastic fragments whose diameter is less than 5 mm, are an emergent pollutant in marine environments. Benthic organisms, such as corals, are at high risk of suffering toxic effects due to MP exposure. This study aims to evaluate the incorporation of polystyrene microparticles (PSm) on the reef building coral species Porites porites. PSm were synthesized employing the simple emulsion and solvent evaporation technique, obtaining round particles with a diameter of ≤5μm. P. porites fragments were exposed to four different PSm concentrations (1, 10, 100, 1000) mg/L over a period of 96 h. Histological techniques were used to evaluate PSm incorporation. No mortality was recorded during the bioassay. PSm incorporation in the gastrovascular cavity was evidenced in all of the tested concentrations. Additionally, in the highest PSm concentration (1000 mg/L), clusters were detected inside the gastrovascular tissue and mesenterial filaments. As complementary information, no statistically significant differences were found across PSm concentrations for catalase enzymatic activity and melanin content (PERMANOVA based on Euclidean distances) as a proxy of general exposure effects. This study found that P. porites is capable of ingesting microplastics, specifically polystyrene microspheres regardless of the tested concentrations, without presenting apparent toxic effects in a 96-hour exposure period. Moreover, it is shown that PSm can be incorporated inside the coral tissue. Further studies are needed to assess the potential toxic effects of MP ingestion with longer exposure times, as well as the possible mechanisms involved in MP recognition and incorporation.

Improvement of Ferulic Acid Antioxidant Activity by Multiple Emulsions: In Vitro and In Vivo Evaluation

Ferulic acid is a derivative of cinnamic acid showing efficacious anti-oxidant activity. It catalyzes the stable phenoxy radical formation, upon absorption of ultraviolet light, giving the strength to ferulic acid for terminating free radical chain reactions. Ultraviolet rays are one of the most dangerous factors that daily assault the skin, causing excessive generation of reactive oxygen species (ROS), which are regarded to be important contributors to a variety of cutaneous alterations. The skin possesses endogenous antioxidant defense systems, but the excess of ROS leads to an oxidant–antioxidant imbalance. Although ferulic acid is daily introduced in human organism with the diet, its bioavailability after oral administration is poor, particularly in the skin. The aim of this investigation was to evaluate three types of emulsions (W/O/W multiple emulsions and two simple emulsions) as suitable formulations for topical application of the active compound. In vitro studies were performed to investigate the stability and release profiles of these systems. Multiple emulsions showed great stability and the best ability to carry and release ferulic acid. In vivo evaluations highlighted their best capability to treat UV-B-induced erythema. These findings suggested multiple emulsions as an innovative and more efficient vehicle for topical application of ferulic acid.

Biomaterial-Based Nanocomposite for Osteogenic Repurposing of Doxycycline.

BackgroundBesides its antimicrobial action, doxycycline (DX) has lately been repurposed as a small-molecule drug for osteogenic purposes. However, osteogenic DX application is impeded by its dose-dependent cytotoxicity. Further, high-dose DX impairs cell differentiation and mineralization.PurposeIntegrating DX into a biomaterial-based delivery system that can control its release would not only ameliorate its cytotoxic actions but also augment its osteogenic activity. In this work, we managed to engineer novel composite DX–hydroxyapatite–polycaprolactone nanoparticles (DX/HAp/PCL) to modify DX osteogenic potential.MethodsEmploying a 23-factorial design, we first optimized HApN for surface-area attributes to maximize DX loading. Composite DX/HAp/PCL were then realized using a simple emulsification technique, characterized using various in vitro methods, and evaluated for in vitro osteogenesis.ResultsThe developed HApN exhibited a favorable crystalline structure, Ca:P elemental ratio (1.67), mesoporous nature, and large surface area. DX/HAp/PCL achieved the highest reported entrapment efficiency (94.77%±1.23%) of DX in PCL-based particles. The developed composite system achieved controlled release of the water-soluble DX over 24 days. Moreover, the novel composite nanosystem managed to significantly ameliorate DX cytotoxicity on bone-marrow stem cells, as well as enhance its overall proliferation potential. Alkaline phosphatase and mineralization assays revealed superior osteodifferentiation potential of the composite system. Quantification of gene expression demonstrated that while DX solution was able to drive bone-marrow stem cells down the osteogenic lineage into immature osteoblasts after 10-day culture, the innovative composite system allowed maturation of osteodifferentiated cells. To the best of our knowledge, this is the first work to elaborate the impact of DX on the expression of osteogenic genes: RUNX2, OSP, and BSP. Further, the osteogenicity of a DX-loaded particulate-delivery system has not been previously investigated.ConclusionOur findings indicate that repurposing low-dose DX in complementary biomaterial-based nanosystems can offer a prominent osteogenic candidate for bone-regeneration purposes.

Novel emulsions–based technological approaches for the protection of omega–3 polyunsaturated fatty acids against oxidation processes – A comprehensive review

Over recent decades, the therapeutic properties and health beneficial effects of omega-3 polyunsaturated fatty acids (omega-3 PUFAs) have been identified. These also contain a number of double bonds which make them highly reactive and, as a consequence, they are susceptible to oxidation. This is one of the main limitations when incorporating them into food matrices. This review article presents the state-of-the-art on the preparation of simple or multiple omega-3 PUFA-based lipid emulsions and other novel systems that have been developed, such as self-assembling systems or solid lipid nanoparticles. Furthermore, the main factors that impact lipid oxidation rate are comprehensively reviewed, highlighting the importance of proteins for increasing the physical stability of food emulsions. Currently, there are several works focused on simple emulsions enriched with omega-3 PUFAs that seek the definition of strategies to allow the control of lipid oxidation. Multiple emulsions and other novel systems are beginning to be considered as a possible alternative to conventional emulsions. This knowledge can be used to facilitate selection of the most appropriate system for the food industry.

Design, Rheology and Physicochemical Characterizations of Oil-in-water Emulsions Stabilized by Waxy Starch Derivatives

Simple emulsions (o/w) stabilized by octenyl succinic anhydrous (OSA) starch were studied. They were characterized by the evaluation of the rheological and physicochemical properties and, the observation under the light microscope in combination with granulometric analysis after formulation. The obtained results demonstrated the effects of the amount of OSA starch on the variation of the diameter of particles, stability of emulsions and their rheological behavior. The best characteristics were found in the emulsion with a ratio 40/60 (o/w) at high OSA starch concentration, because the substitution of the oil phase by the network created by the chains of the modified polysaccharides which could be the major factor in stabilisation of emulsions.

Independent co-delivery of model actives with different degrees of hydrophilicity from oil-in-water and water-in-oil emulsions stabilised by solid lipid particles via a Pickering mechanism: a-proof-of-principle study

HypothesisThe development of vehicles for the co-encapsulation of actives with diverse characteristics and their subsequent controllable co-delivery is gaining increasing research interest. Predominantly centred around pharmaceutical applications, the majority of such co-delivery approaches have been focusing on solid formulations and less so on liquid-based systems. Simple emulsions can be designed to offer a liquid-based microstructural platform for the compartmentalised multi-delivery of actives. ExperimentsIn this work, solid lipid nanoparticle stabilised Pickering emulsions were used for the co-encapsulation/co-delivery of two model actives with different degrees of hydrophilicity. Lipid particles containing a model hydrophobic active were prepared in the presence of either Tween 20 or whey protein isolate, and were then used to stabilise water-in-oil or oil-in-water emulsions, containing a secondary model active within their dispersed phase. FindingsSolid lipid nanoparticles prepared with either type of emulsifier were able to provide stable emulsions. Release kinetic data fitting revealed that different co-delivery profiles can be achieved by controlling the surface properties of the lipid nanoparticles. The current proof-of-principle study presents preliminary data that confirm the potential of this approach to be utilised as a flexible liquid-based platform for the segregated co-encapsulation and independent co-release of different combinations of actives, either hydrophobic/hydrophilic or hydrophobic/hydrophobic, with diverse release profiles.

Space-confined synthesis of nitrilotriacetic acid immobilized magnetic sorbents in aqueous continuous phase of high internal phase emulsion for removing bivalent cadmium

• Space-confined synthesis of NAIMSs-E in aqueous continuous phase of HIPEs is conducted. • High quality sorbents are applied for removing Cd 2+ from aqueous solutions. • DA-NTA moieties not only endow abundant binding sites, but also act as robust anchor. • NAIMSs-E possess sensitive response under magnetic field, fast uptake and large adsorption amount. Monodispersed magnetic sorbents (MMSs) display great potential for adsorptive removal of pollutants, but the conventional methods cannot meet requirements of scalable, time-saving, and energy-efficient fabrication. In this work, space-confined synthesis of nitrilotriacetic acid immobilized magnetic sorbents (NAIMSs-E) in aqueous continuous phase of high internal phase emulsions (HIPEs) was conducted, and as-prepared high quality sorbents (sensitive response to magnetic field, abundant affinity groups, uniform shell size, and stable structure) were applied for removing bivalent cadmium (Cd 2+ ) from aqueous solutions. 2-(Bis-carboxymethyl-amino)-6-{3-[2-(3,4-dihydroxy-phenyl)-ethylcarbamoyl]-propionylamino}-hexanoic acid was firstly synthesized as a robust anchor and a functional modifier onto magnetic Fe 3 O 4 . The effects of synthesis conditions to the morphology and structure were studied, and the forming mechanism based on emulsion nano-reactor was demonstrated. NAIMSs-E are expected to possess fast equilibrium rate, and approximately 90% of the maximum adsorption capacity is achieved within 60 min. The maximum uptake amounts are 49.98 mg g −1 , 80.58 mg g −1 , 176.4 mg g −1 at 288 K, 298 K, and 308 K, respectively, and the monolayer chemisorption based on sharing and transferring of electrons is the main rate-limiting step. Moreover, NAIMSs-E have excellent regeneration and specific affinity towards Cd 2+ , even for actual water samples. In addition, the spontaneous, endothermic, and entropy increased adsorption process is also confirmed. Therefore, this work not only presents a new clue to fabricate MMSs via simple emulsion nano-reactor, but also provides a novel platform for Cd 2+ removal.

Shape memory microparticles with permanent shape reconfiguration ability and near infrared light responsiveness

Smart changing microparticles with controllable shapes have attracted considerable attentions due to their potential applications in microactuators, micromotors and biomedical devices. In this work, a shape memory microsphere based on cellulose acetate (CA) was developed by a simple emulsion solvent evaporation method to perform on-demand shape switch under heat stimulus. The morphology of CA microparticles before and after thermal programing were carefully investigated by both optical microscope and scanning electron microscope, demonstrating their excellent microscopic shape memory properties and shape reconfiguring ability as needed. The temporary and permanent shapes of CA microparticles both can be changed arbitrarily by regulating the stretching condition via a film stretching process to meet various requests. Considering the more convenience of near infrared (NIR) light than direct heat for application, the additional NIR light-induced microscopic shape memory performance was realized by the introduction of multi-walled carbon nanotube into CA microspheres, which can further improve their versatile application potential in various fields.

Controlling the emulsion stability of cosmetics through shear mixing process

The manipulation of emulsion stability for kinetically sustainable cosmetic emulsions is an important technology in cosmetic industry, however the relationship between emulsifying process and long-term emulsion stability has not been elucidated. Herein, the effect of shear mixing process on the stability of oil-in-water cosmetic emulsions is investigated by varying the shear mixing rate, emulsification time, and water phase temperature. The analysis on droplet size distribution and shear viscosity revealed that the strong viscous forces at optimal shear mixing rate of 4000 rpm afforded the fine and uniform droplets for cosmetic emulsions, leading to the improvement of long-term emulsion stability. Moreover, since the prolonged shear mixing induced the destabilization of emulsion droplets through droplet coalescence, optimal shear mixing time of 3 min could improve the kinetic stability of cosmetic emulsions. The dependence of long-term emulsion stability on emulsification temperature was relatively low. The theoretical analysis using the Derjaguin-Landau-Verwey-Overbeek theory demonstrated that the shear mixing rate played a major role in sustaining fine and uniform cosmetic emulsions with long-term stability. The present study can greatly contribute to the fabrication of functional cosmetic emulsions with long-term stability by controlling the shear mixing parameters in simple emulsification process.