scholarly journals Calculation Methods of Solution Chemical Potential and Application in Emulsion Microencapsulation

Molecules ◽  
2021 ◽  
Vol 26 (10) ◽  
pp. 2991
Author(s):  
Binkai Xu ◽  
Xiangdong Liu ◽  
Bo Zhou
Keyword(s):  
Aqueous Phase ◽  
Chemical Potential ◽  
Sampling Methods ◽  
Double Emulsion ◽  
Biased Sampling ◽  
Calculation Methods ◽  
Polymer Mixtures ◽  
Detection Bias ◽  
Detection Point ◽  
Insertion Techniques

Several new biased sampling methods were summarized for solution chemical potential calculation methods in the field of emulsion microencapsulation. The principles, features, and calculation efficiencies of various biased Widom insertion sampling methods were introduced, including volume detection bias, simulation ensemble bias, and particle insertion bias. The proper matches between various types of solution in emulsion and biased Widom methods were suggested, following detailed analyses on the biased insertion techniques. The volume detection bias methods effectively improved the accuracy of the data and the calculation efficiency by inserting detection particles and were suggested to be used for the calculation of solvent chemical potential for the homogeneous aqueous phase of the emulsion. The chemical potential of water, argon, and fluorobenzene (a typical solvent of the oil phase in double emulsion) was calculated by a new, optimized volume detection bias proposed by this work. The recently developed Well-Tempered(WT)-Metadynamics method skillfully constructed low-density regions for particle insertion and dynamically adjusted the system configuration according to the potential energy around the detection point, and hence, could be used for the oil-polymer mixtures of microencapsulation emulsion. For the macromolecule solutes in the oil or aqueous phase of the emulsion, the particle insertion bias could be applied to greatly increase the success rate of Widom insertions. Readers were expected to choose appropriate biased Widom methods to carry out their calculations on chemical potential, fugacity, and solubility of solutions based on the system molecular properties, inspired by this paper.

scholarly journals A new theory for membrane efficiency coefficient of compacted clay

2020 ◽  
Vol 218 ◽  
pp. 02033
Author(s):  
Zhaoyang Song ◽  
Changfu Wei ◽  
Chenggang Zhao
Keyword(s):  
Pore Water ◽  
Calculation Method ◽  
Void Ratio ◽  
Chemical Potential ◽  
Negative Charge ◽  
Ion Concentration ◽  
Efficiency Coefficient ◽  
Compacted Clay ◽  
Calculation Methods ◽  
Change Of Porosity

A new method for calculation the membrane efficiency coefficient w of compacted clay is proposed in this paper. The influence of fixed negative charge on the surface of clay minerals is considered. What’s more, the change of porosity during deformation is considered. Based on the chemical potential of specimens, the true ion concentration in pore-water is obtained. Based on the true ion concentration in pore water, the disjoining pressure considering fixed negative charge inside soils and the change of void ratio is proposed. A new calculation method for the membrane efficiency coefficient of compacted clay is established. The test data of w considering different porosity are calculated and the calculated results are compared with the traditional calculation methods. The new calculation methods of w provide a more physical-based theory for environmental geotechnical engineering.

An Approach to Sorption on Minerals Making Use of Surface Phase Thermodynamics

2003 ◽  
Vol 807 ◽  
Author(s):  
Allan T. Emrén
Keyword(s):  
Series Expansion ◽  
Aqueous Phase ◽  
Chemical Potential ◽  
Solid Phase ◽  
Surface Complexation ◽  
Performance Assessments ◽  
Surface Phase ◽  
Free Enthalpy ◽  
End Members ◽  
Model Curve

ABSTRACTIn performance assessments for nuclear wastes repositories, Kd values are often used to describe sorption of radionuclides on fracture surfaces. The weakness of the Kd concept is that values determined under certain conditions can only be used when the chemistry is similar to those. Alternatives include surface complexation models. The problem with such models is that the parameters required are not easily determined, and thus are missing for several systems.Another alternative is to use surface phase thermodynamics. Such a theory has been developed, in which the surface of a solid phase and the species adsorbed upon it are treated as a separate phase of variable composition. The composition is described in terms of pure end members. For each end member, the free enthalpy is described by a series expansion. To calculate coefficients, the theory makes use of the fact that at equilibrium, the chemical potential of a component has the same value in all phases. Thus, speciation of the bulk aqueous phase can be used. Making use of only the linear term in the expansion, one measured Kd value is enough to determine the corresponding coefficient.The theory has been applied to sorption of U(VI) on alumina with the aid of data from the literature. The coefficient was determined from the measured Kd values in the interval pH = 4 – 12. The resulting model curve was found to agree reasonably well with observed values, although the Kd varies by a factor of 200.

scholarly journals Donnan Potentials in Aqueous Phase-Separated Polymer Mixtures

Langmuir ◽  
2014 ◽  
Vol 30 (20) ◽  
pp. 5755-5762 ◽  
Author(s):  
Mark Vis ◽  
Vincent F. D. Peters ◽  
R. Hans Tromp ◽  
Ben H. Erné
Keyword(s):  
Aqueous Phase ◽  
Polymer Mixtures

scholarly journals Determination of the chemical potential using energy-biased sampling

2005 ◽  
Vol 123 (5) ◽  
pp. 054105 ◽  
Author(s):  
R. Delgado-Buscalioni ◽  
G. De Fabritiis ◽  
P. V. Coveney
Keyword(s):  
Chemical Potential ◽  
Biased Sampling

The Preparation Of PLGA-PLL-Peg Nanoparticles Simultaneously Loaded With Daunorubicin and Tetrandrine By Modified Double-Emulsion Method

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 4918-4918
Author(s):  
Ran Liu ◽  
Yonglu Wang ◽  
Liyao Wang ◽  
Jian Cheng ◽  
Guohua Xia ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Particle Size ◽  
Aqueous Phase ◽  
Conflicts Of Interest ◽  
Double Emulsion ◽  
Volume Ratio ◽  
Processing Parameters ◽  
Diffusion Method ◽  
Transmission Electron ◽  
Efficient Delivery

Abstract A functional polymer composed of PLGA, PLL and PEG was synthesized, which was used as carrier material for fabricating drug delivery system of nanoparticles. PLGA-PLL-PEG nanoparticles simultaneously loaded with daunorubicin (DNR) and tetrandrine (Tet) were prepared in order to inhibit MDR activity and enhance the antitumor activity of DNR. A modified double-emulsion solvent evaporation/diffusion method was used to increase the incorporation of DNR (hydrophilic) and Tet (hydrophobic) into PLGA-PLL-PEG nanoparticles (NPs). The influence of various processing parameters on particle size and drug loadings were investigated systematically, such as the molecular weight, such as the molecular weight and concentration of PLGA-PLL-PEG, volume ratio of acetone to dichloromethane, PVA concentration in the external aqueous phase, the volume ratio of internal aqueous phase to external aqueous phase and the surfactants of internal aqueous phase. The particle size of the nanoparticles produced by optimized formulation and preparation was 213.0±12 nm (n = 3) with low polydispersity index (0.075 ± 0.023, n = 3). Transmission electron microscopy (TEM) examination showed that the morphology of the prepared nanoparticles was spherical in shape with a smooth surface. The drug loadings were 3.63±0.15% for DNR and 4.27±0.13% for Tet (n = 3). The entrapment efficiencies were 70.23±1.91% for DNR and 86.5±0.7% for Tet (n = 3). The release of DNR and Tet were sustained over one week. The PLGA-PLL-PEG-NPs formulation was potentially useful for hydrophilic and hydrophobic drugs that require efficient delivery to cancer cells. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Encapsulation of lipophilic fragrance by polymerization of the intermediate aqueous phase of an oil-in-water-in-oil (O/W/O) double emulsion

2019 ◽  
Vol 10 (30) ◽  
pp. 4154-4162 ◽  
Author(s):  
Margot Stasse ◽  
Tiphaine Ribaut ◽  
Véronique Schmitt ◽  
Valérie Héroguez
Keyword(s):  
Aqueous Phase ◽  
Double Emulsion ◽  
Lipophilic Compounds ◽  
Oil In Water

This paper deals with the encapsulation of lipophilic compounds in an oil-in-water-in-oil (O/W/O) double emulsion.

scholarly journals Effect of pH on the stability of W1/O/W2 double emulsion stabilized by combination of biosilica and Tween-20

2018 ◽  
Vol 215 ◽  
pp. 01028 ◽  
Author(s):  
Lanny Sapei ◽  
Tokok Adiarto ◽  
Roi Handomo ◽  
Sonny Hutomo Chandra
Keyword(s):  
Aqueous Phase ◽  
Rice Husk ◽  
Environmental Sustainability ◽  
Double Emulsion ◽  
Continuous Phase ◽  
Tween 20 ◽  
Acidic Ph ◽  
Effect Of Ph ◽  
Primary Emulsion ◽  
The Stability

Indonesia is amongst agricultural countries whose majority of the population consume rice as their staple food. Rice rice production tends to increase year by year followed by the increasing of their byproducts such as rice husks. The majority of rice husk waste has been generally thrown away by burning on site which cause pollution and may negatively impact on the environmental sustainability. In fact, rice husk waste contains of about 20% silica which potentially be used as emulsion stabilizers. Biosilica could stabilize the interface between water and oil due to their hydrophilicity and hydrophobicity characteristics in nature. However, their wettability was greatly influenced by pH. In this experiment, the effect of pH of the outer continuous phase (W2) was investigated. The primary emulsion (W1/O) was prepared by mixing a 40% water phase containing gelatin 3% w/w relative to the aqueous phase and Tween-20 of 1.1% w/w relative to the primary emulsion with the remaining oil phase for 5 minutes. The primary emulsions were then dispersed into the aqueous phase (W2) of various pH (2; 3; and 5.7) by using a mixture of Tween-20 and biosilica as emulsifiers. The result showed that the most stable double emulsion was obtained upon the acidic pH of 2. There was no differences between the stability of double emulsion prepared at pH 2 and that of pH 3 after 7 days. However those prepared without pH adjustment (5.7) tended to be instable in the long-term. This implied that acidic pH would increase the packing density of biosilica in the interfaces thus enhancing the barrier properties of the droplets against coalescences. A stable food grade double emulsion would be very beneficial to develop low-fat emulsion products in various food applications. Furthermore, the inner aqueous phase could be used as a vehicle to encapsulate bio-active agents such as nutrients or antioxidants for the advancement of developments of functional food products.

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