Emulsions Stabilized with poly(Hydroxyethyl Acrylate-co-Coumaryl Acrylate-co-2-Ethylhexyl acrylate)

Thermo- and photo-responsive emulsions were prepared using mineral oil as an oil phase and a thermo- and-photo-sensitive polymer as an emulsifier. Hydroxyethyl acrylate (HEA) was copolymerized with Coumaryl acrylate (CA) and 2-Ethylhexyl acrylate (EHA) by a free radical reaction with the content of CA in the reaction mixture being varied (0, 0.5, 1, 2, 3 mol%) and the content of EHA being kept constant (2 mol%). CA was used as a photo-responsive comonomer and EHA was used as a hydrophobic comonomer to endow the copolymer with amphiphilicity. The copolymers prepared using the HEA/CA/EHA mixture where CA content was 1, 2, 3 mol% exhibited a phase transition in the range of 20°C– 45°C, and the phase transition temperature decreased with increasing the content. The CA of the copolymers was readily dimerized under the irradiation of UV (365 nm. 400 W) and the dimerization degree was 27%–47% in 60 min. The droplet size of emulsions significantly increased with increasing the temperature from 27°C- 50°C, possibly due to the thermal contraction of the copolymers. Also, the size markedly increased by 60 min-irradiation of the UV light, possibly because of the photo collapse of the copolymers.     

A Study on the Preparation,Structure, and Properties of Microcrystalline Cellulose

Abstract

The preparation, structure, and properties of microcrystalline cellulose (MCC) from rice straw were investigated by IR, x-ray, viscometry, polarizing microscope, SEM, etc. The results are as follows:

1. The leveling-off degree of polymerization (LODP) obtained from rice straw is about 80–150. The dimensions of MCC granules are 20–30 μm length, 0.5–0.8 μm thick, and the crystallinity is about 80%.

2. The aqueous suspension of a certain concentration of MCC can form a gel under the effect of shear force. The viscosity of MCC gel increased with an increasing content of MCC in water. A sharper increase of viscosity occurred in the 3–6% range.

3. The addition of one or two valence salts into the MCC gel increased the viscosity.

4. The viscosity of MCC gel has its maximum value at pH 8.

5. The MCC gel as an emulsifying agent can form a stable emulsion in the oil/water system when the ratio of oil/water is below 6/4.     

Effect of high-intensity ultrasound on the physicochemical properties,microstructure, and stability of soy protein isolate-pectin emulsion

In this study, an emulsion stabilized by soy protein isolate (SPI)-pectin (PC) complexes was prepared to investigate the effects of high-intensity ultrasound (HIU) treatment (150–600 W) on the physicochemical properties, microstructure, and stability of emulsions. The results found that the emulsion treated at 450 W showed the best emulsion stability index (ESI) (25.18 ± 1.24 min), the lowest particle size (559.82 ± 3.17 nm), the largest ζ-potential absolute value (16.39 ± 0.18 mV), and the highest adsorbed protein content (27.31%). Confocal laser scanning microscopy (CLSM) and atomic force microscopy (AFM) revealed that the emulsion aggregation was significantly improved by ultrasound treatment, and the average roughness value (Rq) was the smallest (10.3 nm) at 450 W. Additionally, HIU treatment reduced the interfacial tension and apparent viscosity of the emulsion. Thermal stability was best when the emulsion was treated at 450 W, D₄₃ was minimal (907.95 ± 31.72 nm), and emulsion separation also improved. Consequently, the creaming index (CI) was significantly decreased compared to the untreated sample, indicating that the storage stability of the emulsion was enhanced.     

Fabrication of emulsions prepared by rice bran protein hydrolysate and ferulic acid covalent conjugate: Focus on ultrasonic emulsification

The aim of the paper was to investigate the effect of ultrasonic emulsification treatment on the fabrication mechanism and stability of the emulsion. The covalent conjugate made with rice bran protein hydrolysate (RBPH) and ferulic acid (FA) was used as the emulsifier. The effects of high intensity ultrasound (HIU) power with different level (0 W, 150 W, 300 W, 450 W and 600 W) on the stability of emulsion were evaluated. The results showed that ultrasonic emulsification can significantly improve the stability of the emulsions (p < 0.05). The emulsion gained better stability and emulsifying property at 300 W. It was able to fabricate emulsion with smaller particle size, more uniform distribution and higher interfacial protein content. It was confirmed by fluorescent microscopy and cryo-scanning electron microscopy (cryo-SEM) furtherly. And it was also proved that the emulsion treated by proper HIU treatment at 300 W had better storage stability. Excessive HIU treatment (450 W, 600 W) had negative effects on the stability of emulsion. The stability of emulsion (300 W) against different environmental stresses was further explored, which established a theoretical basis for the industrial application of emulsion in food industry.     

Emulsions stabilised by casein and hyaluronic acid: Effects of high intensity ultrasound on the stability and vitamin E digestive characteristics

This study aimed to prepare an emulsion stabilised by an ultrasound-treated casein (CAS)-hyaluronic acid (HA) complex and to protect vitamin E during in vitro digestion. It was found that high-intensity ultrasound (HIU) treatment significantly changed the hydrogen bonding, electrostatic interaction and hydrophobic interaction between CAS and HA, reduced the particle size of the CAS-HA complex, increased the intermolecular electrostatic repulsion, and thus significantly improved the emulsifying properties of the CAS-HA complex. Meanwhile, the creaming index (CI) and confocal laser scanning microscopy images showed that the stability of the CAS-HA-stabilised emulsion was the best when treated at 150 W for 10 min, which could be attributed to the enhanced adsorption capacity of the CAS-HA complex at the oil–water interface and the viscosity of the formed emulsion. In vitro digestion experiments revealed that the emulsion stabilised by the ultrasound-treated CAS-HA complex had a good protective effect on vitamin E. This study is significant for the development of emulsions for the delivery of lipophilic nutrients.     

聚合物中空微球的合成策略（英文）

在过去的20年中,聚合物中空微球由于其独特的结构和优异的性质受到了广泛的关注.它们表现出低密度、高比表面积和高负载力的特性,在催化、药物递送及能量存储等领域中展现出巨大的应用前景.本文综合评述了聚合物中空微球的合成策略,主要包括模板法、乳液聚合法、自组装与及微流控等,并详细阐述和讨论了这些合成策略的原理、典型过程以及优缺点.同时,还指出了现有合成策略面临的挑战以及聚合物中空微球存在的不足,并对聚合物中空微球的制备和应用前景进行了展望.     

Shortwave Infrared Fluorofluorophores for Multicolor In Vivo Imaging**

Developing chemical tools to detect and influence biological processes is a cornerstone of chemical biology. Here we combine two tools which rely on orthogonality– perfluorocarbons and multiplexed shortwave infrared (SWIR) fluorescence imaging– to visualize nanoemulsions in real time in living mice. Drawing inspiration from fluorous and SWIR fluorophore development, we prepared two SWIR-emissive, fluorous-soluble chromenylium polymethine dyes. These are the most red-shifted fluorous fluorophores– “fluorofluorophores”—to date. After characterizing the dyes, their utility was demonstrated by tracking perfluorocarbon nanoemulsion biodistribution in vivo. Using an excitation-multiplexed approach to image two variables simultaneously, we gained insight into the importance of size and surfactant identity on biodistribution.     

Engineering the Morphologies of Block Copolymer Particles from the Confined Self-assembly within Emulsion Droplets†

Block copolymers (BCPs) can automatically assemble into various regulated nanoparticles when they are confined within the emulsion droplet because of the structural frustration of polymer chains and the soft template effect of the oil/water interface. In the past few years, great efforts have been made to regulate the morphologies of the resulting BCP particles. In this review article, various strategies for tuning oil/water interfacial properties to engineer the as-formed BCP particles were summarized. Then, the comprehensive scenarios of the applications of the resulting BCP particles were discussed. Finally, the future tendency and challenge of the self-assembly of BCPs confined in emulsion droplet were suggested.