Effect of Addition of Inorganic Salts and Organic Solvents on Hydration and Phase Separation of Polyvinylpyrrolidone in Aqueous Solution

In this work, we used a co-flow microfluidic device with an injection and a collection tube to generate droplets with different layers due to phase separation. The phase separation system consisted of poly(ethylene glycol) diacrylate 700 (PEGDA 700), PEGDA 250, and sodium alginate aqueous solution. When the mixture droplets formed in the outer phase, PEGDA 700 in the droplets would transfer into the outer aqueous solution, while PEGDA 250 still stayed in the initial droplet, breaking the miscibility equilibrium of the mixture and triggering the phase separation. As the phase separation proceeded, new cores emerged in the droplets, gradually forming the second and third layers. Emulsion droplets with different layers were polymerized under ultraviolet (UV) irradiation at different stages of phase separation to obtain microspheres. Microspheres with different layers showed various release behaviors in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF). The release rate decreased with the increase in the number of layers, which showed a potential application in sustained drug release.

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Microscopic Evidence for Phase Separation of Organic Species and Inorganic Salts in Fine Ambient Aerosol Particles

Environmental Science & Technology ◽

10.1021/acs.est.0c02333 ◽

2021 ◽

Vol 55 (4) ◽

pp. 2234-2242

Author(s):

Weijun Li ◽

Lei Liu ◽

Jian Zhang ◽

Liang Xu ◽

Yuanyuan Wang ◽

...

Keyword(s):

Phase Separation ◽

Aerosol Particles ◽

Inorganic Salts ◽

Ambient Aerosol ◽

Organic Species ◽

Microscopic Evidence

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Reverse vesicles as a new system for studying enzymes in organic solvents

Biochemical Journal ◽

10.1042/bj2850373 ◽

1992 ◽

Vol 285 (2) ◽

pp. 373-376 ◽

Cited By ~ 10

Author(s):

A Sánchez-Ferrer ◽

F García-Carmona

Keyword(s):

Aqueous Solution ◽

Organic Solvents ◽

Reverse Micelles ◽

Active Form ◽

Ionic Surfactant ◽

New Approach ◽

Optically Transparent ◽

Reverse Vesicles ◽

Dodecyl Ether ◽

New System

A new approach to the study of enzyme activity in organic solvents has been developed by using optically transparent reverse vesicles. Polyphenol oxidase was incorporated in an active form into the above ternary system formed by the non-ionic surfactant tetra(ethylene glycol) dodecyl ether/n-dodecane/water. The enzyme in this microenvironment, surprisingly, showed an apparent positive co-operativity which has never before been described either in aqueous solution or in reverse micelles. In addition, the Vmax. expressed was similar to that in water and twice that displayed in reverse micelles.

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Liquid–liquid phase separation in particles containing organics mixed with ammonium sulfate, ammonium bisulfate, ammonium nitrate or sodium chloride

Atmospheric Chemistry and Physics ◽

10.5194/acp-13-11723-2013 ◽

2013 ◽

Vol 13 (23) ◽

pp. 11723-11734 ◽

Cited By ~ 63

Author(s):

Y. You ◽

L. Renbaum-Wolff ◽

A. K. Bertram

Keyword(s):

Phase Separation ◽

Sodium Chloride ◽

Liquid Phase ◽

Relative Humidity ◽

Ammonium Sulfate ◽

Inorganic Salt ◽

Liquid Phase Separation ◽

Inorganic Salts ◽

Organic Species ◽

Liquid Liquid Phase Separation

Abstract. As the relative humidity varies from high to low values in the atmosphere, particles containing organic species and inorganic salts may undergo liquid–liquid phase separation. The majority of the laboratory work on this subject has used ammonium sulfate as the inorganic salt. In the following we studied liquid–liquid phase separation in particles containing organics mixed with the following salts: ammonium sulfate, ammonium bisulfate, ammonium nitrate and sodium chloride. In each experiment one organic was mixed with one inorganic salt and the liquid–liquid phase separation relative humidity (SRH) was determined. Since we studied 23 different organics mixed with four different salts, a total of 92 different particle types were investigated. Out of the 92 types, 49 underwent liquid–liquid phase separation. For all the inorganic salts, liquid–liquid phase separation was never observed when the oxygen-to-carbon elemental ratio (O : C) &geq; 0.8 and was always observed for O : C < 0.5. For 0.5 &leq; O : C < 0.8, the results depended on the salt type. Out of the 23 organic species investigated, the SRH of 20 organics followed the trend: (NH4)2SO4 &geq; NH4HSO4 &geq; NaCl &geq; NH4NO3. This trend is consistent with previous salting out studies and the Hofmeister series. Based on the range of O : C values found in the atmosphere and the current results, liquid–liquid phase separation is likely a frequent occurrence in both marine and non-marine environments.

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