Anionic Emulsion Research Articles

Influence of replacing Portland cement with anionic asphalt emulsion on vibration damping, mechanical and microstructural properties of concrete

The effect of anionic asphalt emulsion (AE) as partial replacement of Portland cement to enhance the damping properties of concrete was examined. Five concrete mixtures were designed and prepared, increasing AE content from 0 to 40% in overall binder volume, in 10% increments. Loss factor, dynamic moduli, resonant frequencies, and compressive strength were obtained at the age of 7, 28, 90, and 180 days. Results show that the loss factor of concrete increased as the asphalt content increased, whereas the dynamic modulus and resonant frequency decreased. In addition to the viscous damping contributed by asphalt droplets, the more porous microstructure and weaker interfacial transition zones in AE modified concrete can also enhance the damping properties. However, an inverse correlation between concrete strength and damping can be observed with increasing AE content, where the substitution of AE results in a significant decrease in the compressive strength of concrete. Therefore, the anionic AE modified concrete seems to be more suitable for non-structural application where strength is not a key requirement.

Unraveling the Complexities of Silica Nanoparticle Adsorption onto Polymer Latexes in Pickering Emulsion Polymerization.

Incorporating unmodified silica nanoparticles onto polymer latexes to fabricate aqueous polymer dispersions without relying on electrostatic attraction during the Pickering emulsion polymerization process still faces challenges. For negatively charged silica nanoparticles to successfully adsorb onto polymer latexes, particularly in an anionic initiator emulsion polymerization system, they have remained elusive without the use of auxiliary monomers and cationic initiators. This study investigates various experimental parameters, such as emulsion polymerization temperature, monomer solubility, salt concentration, and cation type, to elucidate the factors influencing the adsorption of unmodified silica nanoparticles in Pickering emulsion polymerization. While poly(methyl methacrylate) (PMMA)/SiO2 hybrid latexes can be obtained under pH conditions of 5-6 and at temperatures of 65 °C or below, the loading rate of silica nanoparticles decreases as the reaction temperature increases, resulting in bare PMMA latexes without silica nanoparticle adsorption at temperatures exceeding 70 °C. Introducing styrene (St) into the monomer mixture with methyl methacrylate in a ratio of up to 10 wt % leads to a gradual decrease in silica nanoparticle loading rate, from 27.3 to 8.2 wt %, attributed to the low solubility of St in water. Furthermore, the presence of sodium ions (Na+) is found to be crucial for silica nanoparticle adsorption onto PMMA latexes, as the sodium ions have a stabilizing effect on both the silica nanoparticles and the silica nanoparticle-armored latexes. These findings highlight the complex nature of Pickering emulsion polymerization in the presence of unmodified silica nanoparticles, demonstrating that the loading rate of silica nanoparticles onto polymer latexes is influenced by various factors. These insights pave the way for developing aqueous polymer dispersions with high silica nanoparticle loading rates onto polymer latexes, which is a desirable trait in the coating industry.

Demulsification of surfactant-rich emulsion systems by using amphiphilic or positively charged magnetic nanoparticles

Emulsified oily wastewater comes from many fields, such as oil exploitation, processing, storage and transport, mechanical processing and food and catering industries, causing serious environmental pollution. Considerable part of emulsified oily wastewater was extremely stable and difficult to be treated due to the existence of high-concentration surfactants. Magnetic demulsification of oil-in-water (O/W) emulsion by using magnetic nanoparticles (MNPs) attracted more and more attentions because of its flexible and efficient process; however, the study regarding the treatment of emulsified oily wastewater containing high-concentration surfactant was still few. In this study, amphiphilic dimethyloctadecyl [3-(trimethoxysilyl) propyl] ammonium chloride (DOTAC)-coated MNPs (M-DOTAC) and hydrophilic but highly positively charged quaternized chitosan (QC)-coated MNPs (M-QC) were employed to treat the O/W emulsions containing various contents of anionic and nonionic surfactants. Influence of surfactant type and concentration on the demulsification performance of the two MNPs was investigated in detail. Results showed that M-DOTAC could more effectively demulsify the nonionic surfactant-stabilized emulsion mainly via hydrophobic interaction, while M-QC could more efficiently demulsify the anionic surfactant-stabilized emulsion mainly via electrostatic interaction. With increasing surfactant concentration, the MNPs were still able to completely demulsify the emulsion at a relatively higher dosage. Moreover, when the two classes of MNPs were used together, highly stable emulsion system with containing both anionic and nonionic surfactants could be completely demulsified. These results suggested the synthesized two MNPs could provide simple but powerful approach to treat different emulsified oily wastewaters with containing high-concentration surfactants.

Design, Placement, and Laboratory and Field Evaluation of Rejuvenated Cold Recycled Asphalt Mixtures

Cold recycled (CR) pavements, the combination of reclaimed asphalt pavement and a recycling agent (foamed or emulsified asphalt) at ambient temperatures, can provide a sustainable method to rehabilitate, reconstruct, and construct roadways. However, CR pavement is not a one-for-one replacement of typical asphalt base mixtures. To utilize CR pavements as an alternative to a typical asphalt base mixture or surface course, additional materials such as rejuvenating agents may be needed. This research focuses on the formulation, plant production, and placement on the National Center for Asphalt Technology pavement test track off-ramp, and laboratory evaluation of three rejuvenated CR mixtures, one foamed asphalt CR mixture, and an engineered emulsion CR mixture. These mixtures were subjected to strength and moisture susceptibility testing, along with the indirect tensile asphalt cracking test (IDEAL-CT) and high-temperature indirect tensile test (HT-IDT). The influence of laboratory production versus plant production and the impact of rejuvenators on mixture performance and density were investigated. International roughness index and rut depth data for the off-ramp sections indicate adequate performance, except for the anionic emulsion with bio-based rejuvenator section. Laboratory test results indicate that the addition of rejuvenators into two of the three CR mixtures increased density and decreased moisture susceptibility and increased the CTIndex by at least 35% compared to non-rejuvenated CR mixtures. HT-IDT strengths revealed that two of the three rejuvenated mixtures performed slightly below the non-rejuvenated mixtures.

Synergy evaluation of flavonoid glycosides from Camellia oleifera cake and ionic surfactants on the stability of oil-in-water emulsions

Compared with synthetic surfactants, amino acid surfactants (sodium N-lauroylsarcosinate, SLS) and natural products (flavonoid glycosides from Camellia oleifera cake, FG) have renewability, lower toxicity, and biodegradability, which can reduce energy consumption and environmental pollution during emulsion preparation. Storage time and lipid oxidation are important indicators for evaluating the environmental adaptability of emulsions. However, the effect of complex systems (surfactants and flavonoids) on emulsion performance and its related mechanisms have not yet been thoroughly studied. The oxidative stability, physical stability, and interaction mode of FG-ionic surfactants (SLS/CTAB)-stabilized oil-in-water (O/W) emulsions were explored. The results indicated that FG displayed excellent antioxidant and emulsifying capacity without negative hemolysis. Moreover, FG contributed to the interfacial activity of ionic surfactants. The optimum synergistic ratio of SLS/CTAB-FG was 0.167/0.091. The presence of FG alleviated the stratification of cream volume and retarded Ostwald ripening and droplet coalescence. After storage, the FG-SLS-stabilized emulsions showed the smallest droplet size and the largest emulsion volume. Moreover, the addition of FG effectively reduced the production of harmful substances such as 2-thiobarbituric acid reactive substances (TBARS) and lipid hydroperoxides. A meaningful discovery was that oxidative stability depended strongly on the interaction mechanism between FG and surfactants. FG was more useful for improving the oxidative stability of anionic surfactant-stabilized emulsions. Overall, this study demonstrates that Camellia oleifera cake can serve as an inexpensive and eco-friendly renewable resource for natural emulsifiers and antioxidants, and provides theoretical guidance for its more effective utilization.

Encapsulation of Inorganic Nanoparticles by Anionic Emulsion Polymerization of Diethyl Methylene Malonate for Developing Hybrid Microparticles with Tailorable Composition

Colloidal particle self-assembly into higher-ordered structures has been of great interest due to the promise of creating metamaterials with novel macroscopic properties. The physicochemical properties of these metamaterials can be tailored to achieve composites with tunable functionalities, either by controlling the assembly morphology and/or chemistry of the colloidal building blocks. This work describes a strategy of developing microparticles with a hybrid configuration that have an inorganic and an organic part. The inorganic part comprises functional nanoparticles, which are embedded within an organic polymer particle composed of diethyl methylene malonate polymer [p(DEMM)] prepared using anionic emulsion polymerization. DEMM polymerization is initiated entirely by the presence of hydroxyl anions and the resulting particle diameter can be tuned between 300 nm and 1 micrometer by reaction pH. Inorganic nanoparticles with varying chemistry (TiO2, CdTe, ZnO) can be loaded into the p(DEMM) particle with a controlled weight fraction, as confirmed by thermogravimetric analysis. The colloidal stability of the composite microparticles is seen to be dependent on the ligand coating attached to the inorganic constituent. These results provide a synthetic groundwork for creating hybrid, stimuli-responsive microparticles.

Fabrication of a poly(N-isopropylacrylamide)-grafted alginate composite aerogel for efficient treatment of emulsified oily wastewater

The treatment of emulsion wastewater poses significant challenges. In this study, a novel porous material, namely esterified bagasse/poly(N, N-dimethylacrylamide)/sodium alginate (SBS/PDMAA/Alg) aerogel, was developed for efficient demulsification and oil recovery. By grafting a poly(N-isopropylacrylamide) (PNIPAM) brush onto the SBS/PDMAA/Alg skeleton through free radical polymerization, the resulting aerogel exhibits both surface charge and a molecular brush structure. The aerogel demonstrates remarkable demulsification efficiency for cationic surfactant-stabilized emulsions at various concentrations, achieving a demulsification efficiency of 95.6% even at an oil content of 100 g L−1. Furthermore, the molecular brush structure extends the application range of the aerogel, enabling a demulsification efficiency of 98.3% for anionic and non-ionic surfactant-stabilized emulsions. The interpenetrating polymer network (IPN) structure formed by SBS, PDMAA, and alginate enhances the mechanical stability of the aerogel, enabling a demulsification efficiency of 91.3% even after 20 repeated cycles. The demulsification ability of the composite aerogel is attributed to its surface charge, high interfacial activity, and unique brush-like structure. A demulsification mechanism based on the synergistic effect of surface charge and molecular brush is proposed to elucidate the efficient demulsification process.

Strength and resilient modulus characteristics of emulsion-stabilised demolition wastes in pavement structures

The use of bitumen emulsion has commonly been limited to pavement surface treatments or stabilising virgin aggregates. There is a lack of experimental evidence about the resilient modulus responses of bitumen emulsion-stabilised recycled demolition wastes in pavement applications. The aim of this study is to evaluate the effect of bitumen emulsion on the tensile strength and resilient modulus responses of recycled crushed concrete aggregate and crushed brick for pavement base/subbase course applications. A type of slow-set anionic bitumen emulsion was used at different contents of 0, 1, 2, and 3 % by dry weight of aggregates to prepare compacted specimens. The specimens were dried back to 70 and 90 % of the compaction moisture content to simulate the field conditions. Specimens were next investigated through a comprehensive testing program, including indirect tensile strength, indirect tensile modulus, and repeated triaxial loading tests. Results showed that the tensile strength of the mixtures generally increased as the emulsion content increased. The inclusion of 2 % and 3 % bitumen emulsion to RCC and CB provided the highest indirect tensile resilient modulus (ITMr) at 359 and 310 MPa, respectively, for those samples cured for 3 h. The highest ITMr results were obtained from samples cured for 3 days at 40 °C in a dry state with the inclusion of 2 % emulsion. For CB and RCC specimens, the results were 2808 and 3361 MPa, respectively. However, specimens of CB and RCC with 3 % emulsion that were cured for 3 days at 40 °C and then soaked in water at 25 °C exhibited the highest ITMr at 1981 and 2900 MPa, respectively. The resilient modulus in the majority of the specimens peaked at 2 % emulsion content, which was recommended as the optimum emulsion content. Results also indicated an enhanced resistance to moisture damage in demolition wastes through emulsion stabilisation. This study proposes, validates and promotes the sustainable approach of emulsion stabilisation of recycled aggregates used in the construction of pavement structures.

Optimizing Cement Asphalt Mortar Mixtures for Bridge Expansion Joints in Tropical Climates: Performance and Durability Assessment

In this study, the suitability of various Cement Asphalt Mortar (CAM) mixtures for bridge expansion joint applications in tropical climates was quantitatively assessed. A comprehensive analysis encompassed key properties, including mixing stability, flowability, unconfined compressive strength, expansion characteristics, and resistance to acidic and alkali environments. The influence of high-temperature exposure on unconfined compressive strength and the microstructural features were also examined. The results revealed a discernible trend: lower cement content, in conjunction with anionic Asphalt Emulsion (AE) or epoxy resin, significantly enhanced mixing stability and flowability while contributing to improved unconfined compressive strength and chemical degradation resistance. Notably, epoxy resin emerged as a valuable component in mitigating high-temperature-induced strength reduction, indicating potential promise for CAM mixture design. SEM analysis visually supported these findings by highlighting the microstructural distinctions among CAM mixtures. Quantitatively, the findings indicated that CAM mixtures with a 25% cement content and 75% anionic AE exhibited an 11% improvement in mixing stability, along with a 13% enhancement in flowability, relative to the control mixture with 100% cement. Additionally, CAM mixtures incorporating epoxy resin (at various percentages) with anionic AE exhibited a significant 15% resistance to high-temperature-induced UCS reduction, surpassing other mixtures. The SEM micrographs visually confirmed the superior microstructural connectivity achieved with epoxy resin, further validating the observed enhancements. These quantitative results offer a robust foundation for tailoring CAM mixture compositions to optimize their suitability for rigorous infrastructure projects in tropical climates.

Stability of dodecyl sulfate emulsified asphalt: The overlook effect of dissociated counterions

As an environmentally friendly technology, emulsified asphalt can conserve resources and reduce hazardous fuming during paving, which is pivotal for promoting sustainable road engineering. However, asphalt emulsions with poor stability resulted in performance degradation especially after long-term storage or long-distance transport. The dissociation of anionic asphalt emulsions generates counterions that can potentially induce the emulsifier agglomeration at the asphalt-water interface, subsequently resulting in emulsion destabilization. In this study, two dodecyl sulfate emulsifiers (i.e., sodium lauryl sulphate (SDS) with Na+ counterion, and potassium lauryl sulfate (PDS) with K+ counterion) were employed in the production of asphalt emulsions. The effect of counterion type and concentration on the stability of dodecyl sulfate emulsified asphalt were investigated using storage stability, particle size distribution, and differential scanning calorimetry (DSC) tests. Molecular simulation was used to elucidate the mechanism of how the counterions affected the stability of dodecyl sulfate emulsified asphalt. Due to the fact that K+ counterion has a smaller electrostatic potential energy and a weaker electrostatic interaction with the O atoms in water molecules, PDS emulsified asphalt displayed superior homogeneity, storage stability, and heat stability. The emulsifier molecules adsorbed at the asphalt-water interface diffused into the water phase due to electrostatic attraction when the counterion doping exceeded the crucial value (SDS: 5 wt%, PDS: 4 wt%). Subsequently, the stable monolayer film at the interface dissolved, lowering the stability of the emulsified asphalt. It was challenging for SDS to compress the bilayer created by the headgroup since a limited number of Na+ counterions were accumulated near the headgroup. This hindered SDS from forming a monolayer at the asphalt-water interface, potentially explaining its inferior interfacial stability. Overall, our findings highlight the critical role of counterions in determining the stability of dodecyl sulfate emulsified asphalt, with K+ counterion in PDS emulsified asphalt showing superior stability.

Synthesis of bio‐based modified amphoteric acrylate epoxy emulsion surface sizing agent via RAFT polymerization

AbstractThe synthesis of bio‐based modified amphoteric epoxy modified acrylate sizing emulsion based on reversible addition fragmentation chain transfer (RAFT) polymerization and its application in paper sizing were studied. A macromolecular chain transfer agent for RAFT polymerization was synthesized by the esterification of epoxy resin E‐51 with RAFT agent to eliminate the active groups on RAFT agent. Amphoteric polymer emulsifiers with good emulsification and dispersion effects in acidic and alkaline media were successfully prepared by RAFT polymerization. After neutralization, other monomers were polymerized to access cationic sizing emulsion (acid neutralization) and anionic sizing emulsion (alkali neutralization). The effects of bio‐based monomer content, hydrophilic monomer dimethylaminoethyl methacrylate (DM) content and degree of quaternization on the properties of sizing emulsion and sizing paper were further explored. In addition to the particle size and polymer dispersion index (PDI) of latex particles in different experimental groups, the water resistance, folding resistance, bursting strength, tensile strength and surface roughness of sized paper were analyzed and evaluated. Based on these results, a better sizing emulsion formulation was established. It was confirmed that the addition of bio‐based monomers can improve the sizing performance of paper.

Development of levan-coated PIBCA nanoparticles and their antiproliferative activity against MDA-MB-231 and B16F10 cells

Polysaccharides have been described as a successful alternative in developing nanosystems to reach specific sites. Levan is an exopolysaccharide with several biological activities, including immunostimulant, blood plasma substitute, and drug action prolonging agent. The present work aimed to develop poly-isobutyl cyanoacrylate (PIBCA) nanoparticles coated levan (Np-Lev) and to verify its cytotoxicity in two cancer cell lines. Levan was obtained through the fermentation of ZAG 12 Zymomonas mobilis. The nanoparticles were prepared using the anionic emulsion polymerization technique and characterized in size, zeta potential, morphological analysis, X-ray diffraction, infrared spectroscopy, and thermogravimetric analysis. The cell lines MDA-MB-231 (metastatic breast cancer cells) and B16F10 (melanoma cells) were used to evaluate the antiproliferative activity and cellular uptake of Np-Lev. The technique of obtaining the levan allowed a higher yield than the reference methodology, achieving 71.4% more. The novel nanoparticles (Np-Lev) presented spherical shapes, size of 244 ± 2 nm with homogeneous distribution and zeta potential of −12 ± 1 mV. Characterization techniques, such as infrared spectroscopy and X-ray diffraction, confirmed the presence of levan in the nanoparticles. The thermogravimetric analysis results showed greater thermal resistance when compared to free levan. In addition, Np-Lev were more cytotoxic than levan in both cell lines. This toxicity may be related to the internalization of nanoparticles inside the cells since Np-Lev were captured by the cells, which could increase the activity of levan cytotoxicity. Thus, it was verified a substantial increase in levan yield, also that the levan produced could be used to prepare PIBCA nanoparticles, and finally these Np-Lev showed antiproliferative activity against breast cancer and melanoma cell lines. The results exposed here are of interest to explore levan potential, in addition to nanotechnology, as a promising nanosystem with various biological applications. Further studies are needed to understand the biological behavior of nanoparticles and assess their stability for future therapeutic application.

Ultrastable emulsions constructed by self-assembly of two protein-polyphenol- anionic polysaccharide ternary complexes-stablized high internal phase emulsions

Compared to conventional high internal phase emulsions (HIPEs), ultrastable HIPEs have recently attracted much attention due to much better stability and protection for bioactive compounds. Here, novel food-grade ultrastable HIPEs were successfully constructed. By simply mixing two individual unstable HIPEs (instability in 3 months in open atmosphere) stabilized by ternary complexes of protein (i.e., lactoferrin), two polyphenols (i.e., (−)-epigallocatechin-3-gallate and curcumin) and two anionic polysaccharides (i.e., κ-carrageenan and low methoxylated pectin), respectively, ultrastable mixed-HIPEs (very stable for 1 year or more in open atmosphere) were achieved unexpectedly. The two individual HIPEs underwent liquid-to-gel and viscous-to-elastic transitions during mixing, exhibiting strong structural synergism. The stabilization was ascribed to the electrostatic repulsive interactions and the formed interpenetrating polymer networks hydrogels in continuous phases; their contribution varied according to the binding sequences of protein, polyphenol, and polysaccharide (for ternary complexes) and the combination modes of individual HIPEs (for mixed-HIPEs). The excellent soft material properties of ternary complexes can provide guarantee for the stsability of emulsion droplets, avoiding their rupture caused by strong squeezing in mixed-HIPEs. This finding greatly expands the type of food grade ultrastable HIPEs. Overall, the novel food-grade ultrastable mixed-HIPEs will offer fascinating opportunities for their future applications in food, medical, cosmetic, and tissue engineering products.

Permanent deformation response of demolition wastes stabilised with bitumen emulsion as pavement base/subbase

The stabilisation of the granular base course using binders has been adopted for many years; however, the use of bitumen emulsions has been emerging in recent times. Nevertheless, there is limited knowledge on the deformation behaviour of bitumen emulsion-stabilised recycled demolition wastes, particularly in pavement base and subbase applications. In this study, the effect of bitumen emulsion on the permanent deformation behaviour of two types of recycled demolition wastes, recycled concrete aggregate (RCA) and crushed brick (CB) is evaluated. The aggregate samples were blended with an anionic slow-set bitumen emulsion at different contents of 0, 1, 2, and 3 % by dry weight of aggregates. Compacted specimens were partially dried to achieve target values of 70 and 90 % of their optimum moisture contents to investigate the effect of in-service moisture content. Specimens were next subjected to repeated loading triaxial tests that comprised of multiple stages at varying stress levels to simulate moving loads of vehicles. The shakedown theory was adopted to characterise the blends based on their permanent deformation responses. Most of the proposed blends exhibited a Range B behaviour, i.e., plastic creep responses. Also, CB samples generally experienced higher permanent strain accumulations and hence, inferior permanent deformation responses compared to RCA. The inclusion of bitumen emulsion to the aggregates generally caused a decrease in resilient strains, showing that emulsion-stabilised RCA and CB could provide increased resistance under repeated traffic loading. It was also concluded that higher moisture contents led to higher permanent strains and permanent strain rates.

Efficacy and safety of topical cyclosporine 0.1% in moderate-to-severe dry eye disease refractory to topical cyclosporine 0.05% regimen.

To evaluate the efficacy and safety of 0.1% cyclosporine A cationic emulsion (CsA CE) following prior treatment with 0.05% cyclosporine A anionic emulsion (CsA AE) in moderate to severe dry eye disease (DED). We retrospectively identified patients with moderate-to-severe DED who had shown an inadequate response to twice-daily use of topical 0.05% CsA AE but showed a significant improvement after switching to 0.1% CsA CE daily. Dry eye parameters before and after CsA CE were evaluated by tear break-up time (TBUT), corneal fluorescein staining (CFS), cornea sensitivity, Schirmer's test without anesthetics, and Ocular Surface Disease Index questionnaire. Twenty-three patients, including ten patients with Sjogren syndrome and five patients with rheumatoid arthritis, were reviewed. After a 2-month course of treatment with topical 0.1% CsA CE, significant improvements were noted for CFS (P < 0.001), corneal sensitivity (P = 0.008), and TBUT (P = 0.01). Efficacy was similar in the autoimmune versus nonautoimmune group. 39.1% of patients reported treatment-related adverse events, while the majority was transient instillation pain. Visual acuity and intraocular pressure had no significant changes during the study. In patients with moderate to severe DED refractory to 0.05% cyclosporine, shifting to 0.1% cyclosporine showed improvement in objective signs but with lower treatment tolerability in the short term.

Investigation on self-healing, anti-fogging and anti-frosting performances of silica sol modified waterborne polyurethane coatings

In this study, a series of silica sol modified polyurethane composite emulsions were fabricated via incorporating silica sol precursor into anionic silanol-terminated polyurethane emulsion, which was obtained via three steps, including (1) reacting excess hexamethylene diisocyanate (HDI) with polybutylene glycol (PBG), 2,2-dimethylhydroxypropionic acid (DMPA), bis(2-hydroxyethyl) disulfide (HEDS) in a stepwise process using dibutyltin diacetate (DBTA) as the catalyst, (2) neutralizing the resulting prepolymer with triethylamine and end-capping with 3-aminopropyltriethoxysilane (APTES), and (3) dispersing the resulting silanol-terminated polyurethane in water under stirring. The reaction products were characterized by fourier transform infrared (FT-IR) spectroscopy, hydrogen proton nuclear magnetic resonance (1H NMR) spectroscopy, Raman spectroscopy and permeation gel chromatography (GPC). The swelling degree and gel content analysis confirmed the formation of crosslinking network in the composite coatings formed after drying the composite emulsions. The self-healing performances of the coatings were investigated by differential scanning calorimetry (DSC), dynamic thermomechanical analysis (DMA), scanning electron microscopy (SEM) and tensile mechanical tests, and the anti-fogging and anti-frosting behaviors of the composite coatings were analyzed by UV–visible spectroscopy, reflectance spectroscopy, water contact angle test and optical photometry. Based on the measurements, the self-healing process, the anti-fogging and anti-frosting mechanism were discussed. At suitable amount of HEDS, this coating exhibited excellent self-healing performances with the self-healing efficiency up to 95.9 % because of the high moving ability of the chains. After self-healing, these coatings displayed the same anti-fogging and anti-frosting properties as those before self-healing. The silica sol component was found to increasing both the polar groups and crosslinking degree, endowing the composite coating with durable anti-fogging and anti-frosting properties.

Low-temperature thermal cracking performance of waterborne epoxy asphalt emulsion mastic based on bending beam rheometer (BBR)

This research experimentally investigated the low-temperature thermal cracking performance of waterborne epoxy asphalt emulsion (WEA) mastic. A total of sixteen WEA mastics were prepared by utilizing two mineral fillers (Portland cement as an active filler and limestone dust as an inert filler) and two WEAs (anionic and cationic emulsions). They were then subjected to the bending beam rheometer (BBR) test. Based on the test results, four parameters, creep stiffness at loading time of 60 s, S(60 s), creep rate at loading time of 60 s, m(60 s), m(60 s)/S(60 s), and the difference in critical low temperature performance grade limiting temperatures, ΔTc, were calculated to evaluate WEA mastics’ low-temperature creep and relaxation properties. The results showed that mineral fillers diminished the susceptibility of WEA material to stiffness growth with testing temperature drop. The charge type of WEA emulsion showed a significant effect on the low-temperature performance grade of WEA-cement mastic. The ΔTc value of anionic WEA-cement mastic was 10℃ more than that of cationic WEA-cement mastic. The creep stiffness master curves fitted by Christensen-Anderson-Marasteanu (CAM) model could better understand the low-temperature creep characteristics of WEA mastics in a wide range of time domains.

Colloidal dynamics of emulsion droplets in mouth

The interaction of emulsions with the tongue is key to the sensory appeal of food and can potentially be exploited for oral/buccal pharmaceutical delivery. Whilst there is good understanding of the different mucoadhesive forces governing emulsion interaction with the tongue, their relative importance is not well understood. In addition, the physical location of emulsions within the saliva papillae on the tongue is not understood at all. A combination of ex vivo salivary film, and in vivo oral coating experiments were used to determine the importance of different mucoadhesive forces. Mucoadhesion of cationic emulsions was largely driven by electrostatic complexation. SDS-PAGE of the in vivo saliva coating highlighted that mucins were largely responsible for cationic emulsion mucoadhesion. Anionic emulsions were bound via hydrophobic/steric interactions to small salivary proteins typically located away from the mucin anchor points. The physical location and clustering of emulsions relative to the salivary film/papillae was probed via the invention of a fluorescent oral microscope. Cationic emulsions were densely clustered close to the papillae whilst anionic emulsions were suspended in the salivary film above the papillae. Interestingly, non-ionic emulsions were also trapped within the salivary film above the papillae as individual droplets. These findings highlight that whilst electrostatic complexation with saliva is a powerful mucoadhesive force, hydrophobic and steric interactions also act to induce oral retention of emulsions. The differences in physical location and clustering of emulsions within the salivary film hint at the 3D locations of the different salivary proteins driving each mucoadhesive interaction. This novel understanding of emulsion saliva/papillae interactions has potential to aid efficacy of buccal pharmaceutical delivery and the reduction of astringency in plant-based foods.

Phytocosmetic Emulsion Containing Extract of Morus nigra L. (Moraceae): Development, Stability Study, Antioxidant and Antibacterial Activities

Morus nigra L. is a species popularly known in the Northeast of Brazil as “amora miúra”. This species is a source of flavonoids with antioxidant activity. Antioxidants play an important role in the preservation of cosmetic formulations, and they neutralize free radicals. The objective of this study was to develop a topical emulsion containing leaf extract of Morus nigra L., as well as to evaluate the stability, antioxidant and antibacterial activities of the formulations. A crude hydroalcoholic (70%) extract of M. nigra leaves (MnCE) was submitted to high-performance liquid chromatography with diode-array detection (HPLC–DAD) analysis and incorporated into an anionic base emulsion. Antioxidant activity was evaluated according to the DPPH (2,2-diphenyl-1-picrylhydrazyl) method, and the stability of the formulation was assessed for 90 days, submitting the emulsion to storage at 4, 20, and 37 °C. Microdilution techniques evaluated the antibacterial activity and a challenge test assessed the microbiological stability. Analysis by HPLC–DAD identified the flavonoids rutin and isoquercetin in the M. nigra extract. The emulsion and plant extract presented antioxidant activity, and the stability of the emulsion was preserved in terms of pH value and viscosity—which did not show significant changes, except for the spreadability, which was affected by the temperature. The antioxidant activity did not change significantly, except for the sample under 4 °C, which showed a considerable decrease in activity. The crude hydroalcoholic extract and formulation showed antimicrobial activity and the emulsion was considered stable in terms of organoleptic, physicochemical, and microbiological properties.

Defining Endocytic Pathways of Fucoidan-Coated PIBCA Nanoparticles from the Design of their Surface Architecture.

PurposeThis work investigated the endocytic pathways taken by poly(isobutylcyanoacrylate) (PIBCA) nanoparticles differing in their surface composition and architecture, assuming that this might determine their efficiency of intracellular drug delivery.MethodsNanoparticles (A0, A25, A100, R0, R25 ) were prepared by anionic or redox radical emulsion polymerization using mixtures of dextran and fucoidan (0, 25, 100 % in fucoidan). Cell uptake was evaluated by incubating J774A.1 macrophages with nanoparticles. Endocytic pathways were studied by incubating cells with endocytic pathway inhibitors (chlorpromazine, genistein, cytochalasin D, methyl-ß-cyclodextrin and nocodazole) and nanoparticle uptake was evaluated by flow cytometry and confocal microscopy.ResultsThe fucoidan-coated PIBCA nanoparticles A25 were internalized 3-fold more efficiently than R25 due to the different architecture of the fucoidan chains presented on the surface. Different fucoidan density and architecture led to different internalization pathway preferred by the cells. Large A100 nanoparticles with surface was covered with fucoidan chains in a loop and train configuration were internalized the most efficiently, 47-fold compared with A0, and 3-fold compared with R0 and R25 through non-endocytic energy-independent pathways and reached the cell cytoplasm.ConclusionInternalization pathways of PIBCA nanoparticles by J774A.1 macrophages could be determined by nanoparticle fucoidan surface composition and architecture. In turn, this influenced the extent of internalization and localization of accumulated nanoparticles within cells. The results are of interest for rationalizing the design of nanoparticles for potential cytoplamic drug delivery by controlling the nature of the nanoparticle surface.Graphical abstract Supplementary InformationThe online version contains supplementary material available at 10.1007/s11095-022-03202-4.