Phase behaviour of a non-ionic surfactant–polymeric solution–water system during the phase inversion process

The Viscosity and Combustion Characteristics of Single-Droplet Water-Diesel Emulsion

Diesel fuel exhibits excellent combustion characteristics and stability. However, diesel use is becoming restricted because of its associated environmental problems. Fuel emulsification, which increases efficiency and reduces pollution, became the solution of environmental problem. In this study, five water:diesel emulsions with mass ratios (0.3, 0.6, 1.0, 1.2, and 1.5) via ultrasonication were synthesized with and without surfactant. The optimal water:diesel ratio (=1:1) of an emulsion containing the surfactant was found by analyzing fuel concentration, mixing time, and viscosity. The combustion characteristics of single-droplet optimal emulsions were studied through ignition delay, burning rate, and total droplet lifetime at high temperature (400–700 °C) and pressure (1–15 bar), and micro-explosion phenomenon was observed. Although the ignition delay of emulsion increased, the total lifetime of the emulsion droplet was lower than that of diesel under 5 bar, 600 °C condition.

Preparation of Fenpropathrin Nanoemulsion by Phase Inversion Temperature Method and Its Study on Performance

In this study, 8% fenpropathrin nanoemulsion was prepared by phase inversion temperature (PIT) method with 8% xylene and 4% solvent oil 150# as the solvent. The characteristics of this nanoemulsion were tested and compared with emulsifiable concentrate (EC). The size of 8% fenpropathrin nanoemulsion was 62.99[Formula: see text]nm, which was much smaller than that of 20% fenpropathrin EC (459.00[Formula: see text]nm). The mixed surfactants were added in fenpropathrin nanoemulsion with DBS-Ca:LAE at 1:2 to increase the stability, and the concentration of the mixed surfactants at 10[Formula: see text]wt.% showed the highest stability and much better synergism and surface activity. The absolute zeta potential of fenpropathrin nanoemulsion was much higher than that of EC, which can effectively prevent the cohesion between particles. Field control test also revealed that the 200[Formula: see text]mg/L, 100[Formula: see text]mg/L and 50[Formula: see text]mg/L fenpropathrin nanoemulsion had higher efficacy than 100[Formula: see text]mg/L fenpropathrin EC (contrast pesticide) in 4th, 7th, 15th days, respectively. In conclusion, nanoemulsion has a great application prospective in the future.

Sinomenine-loaded microcapsules fabricated by phase reversion emulsification-drying in liquid method: An evaluation of process parameters, characterization, and released properties

Sinomenine is a natural alkaloid with important biological activities (e.g. anti-cancer, anti-inflammatory, and anti-allergic). However, the unstability and short half-life absolutely limited its application to foods. Microencapsulation technology can offer a way to solve these issues. In this study, polylactic acid microcapsules loading sinomenine hydrochloride were fabricated by phase inversion emulsification-drying in liquid technique. The results showed that microcapsules had nice spherical shape, uniform particle size, and free flowing. The encapsulation efficiency was 89.2% and drug loading was 8.9% under the optimal conditions. In vitro release assays demonstrated that release of sinomenine from microcapsules was sustained and slow. Moreover, it was found that the sinomenine release fitted Fickian diffusion mechanism. The results of cytotoxicity study showed that sinomenine-loaded microcapsules were biocompatible. Sinomenine-loaded microcapsules could inhibit the growth of MDA-MB-231 cells using methyl thiazolyl tetrazolium assay. In summary, polylactide microcapsules exhibit excellent properties for sinomenine that can be used in drug or food industry.

Water-in-water emulsions based on incompatible polymers and stabilized by triblock copolymers-templated polymersomes

Aqueous solutions containing a mixture of polyethylene glycol (PEG) and dextran homopolymers form an aqueous two-phase system which can be emulsified to give a water-in-water emulsion. We show how these emulsions can be stabilized using triblock polymers containing poly[poly(ethylene glycol) methyl ether methacrylate] (PEGMA), poly (n-butyl methacrylate) (BuMA), and poly[2-(dimethylamino) ethyl methacrylate] (DMAEMA) blocks of general structure Pp-Bb-Dd, in which the middle BuMA block is hydrophobic. Low-energy input stirring of mixtures containing equal volumes of PEG- and dex-rich aqueous phases plus 1 wt % of Pp-Bb-Dd stabilizer all form dex-in-PEG emulsions (for the range of Pp-Bb-Dd triblock polymers used here) which have a polymersome-like structure. In favorable cases, the emulsion drop (or templated polymersome) sizes are a few micrometers and are stable for periods in excess of 6 months. The emulsions can be inverted from dex-in-PEG to PEG-in-dex by increasing the volume fraction of dex-rich aqueous phase. We demonstrate that both high and low molecular weight fluorescent solutes "self-load" into either the dex- or PEG-rich regions and that solute mass transfer across the water-water interface occurs on a timescale of less than 1 min.

Nanoemulsions prepared by a low-energy emulsification method applied to edible films

Catastrophic phase inversion (CPI) was used as a low-energy emulsification method to prepare oil-in-water (O/W) nanoemulsions in a lipid (Acetem)/water/nonionic surfactant (Tween 60) system. CPIs in which water-in-oil emulsions (W/O) are transformed into oil-in-water emulsions (O/W) were induced by changes in the phase ratio. Dynamic phase inversion emulsification was achieved by slowly increasing the water volume fraction (fw) to obtain O/W emulsions from water in oil emulsions. Composition and processing variables were optimized to minimize droplet size and polydispersity index (PdI). It was found that addition of the continuous phase to the dispersed phase following the standard CPI procedure resulted in the formation of oil droplets with diameters of 100-200 nm. Droplet size distribution during CPI and emulsification time depended on stirring speed and surfactant concentration. Droplet sizes in the inverted emulsions were compared to those obtained by direct emulsification: The process time to reach droplet sizes of around 100 nm was reduced by 12 times by using CPI emulsification. The Acetem/water nanoemulsion was also used as a carrier to incorporate oregano and cinnamon essential oils into soy protein edible films. The resulting composite films containing oregano oil showed better moisture barrier and mechanical properties compared to soy protein films.

Influence of phase inversion on the formation and stability of one-step multiple emulsions

A novel method of preparation of water-in-oil-in-micelle-containing water (W/O/W(m)) multiple emulsions using the one-step emulsification method is reported. These multiple emulsions were normal (not temporary) and stable over a 60 day test period. Previously, reported multiple emulsion by the one-step method were abnormal systems that formed at the inversion point of simple emulsion (where there is an incompatibility in the Ostwald and Bancroft theories, and typically these are O/W/O systems). Pseudoternary phase diagrams and bidimensional process-composition (phase inversion) maps were constructed to assist in process and composition optimization. The surfactants used were PEG40 hydrogenated castor oil and sorbitan oleate, and mineral and vegetables oils were investigated. Physicochemical characterization studies showed experimentally, for the first time, the significance of the ultralow surface tension point on multiple emulsion formation by one-step via phase inversion processes. Although the significance of ultralow surface tension has been speculated previously, to the best of our knowledge, this is the first experimental confirmation. The multiple emulsion system reported here was dependent not only upon the emulsification temperature, but also upon the component ratios, therefore both the emulsion phase inversion and the phase inversion temperature were considered to fully explain their formation. Accordingly, it is hypothesized that the formation of these normal multiple emulsions is not a result of a temporary incompatibility (at the inversion point) during simple emulsion preparation, as previously reported. Rather, these normal W/O/W(m) emulsions are a result of the simultaneous occurrence of catastrophic and transitional phase inversion processes. The formation of the primary emulsions (W/O) is in accordance with the Ostwald theory ,and the formation of the multiple emulsions (W/O/W(m)) is in agreement with the Bancroft theory.