Phase Separation Time Research Articles

Screening and evaluation of phase change absorbents by molecular polarity index: Experimental and quantum chemical calculation studies

Phase change absorbents have recently received increasing attention due to their potential to reduce the energy penalty of CO2 capture. However, its complex composition makes the prediction of phase separation performance difficult. Phase separation behavior and phase separation rate have been investigated for the amine-aqueous 5.0 M amine blends by experimental and quantum chemical calculations (including MPI, hydrogen bonds and Gibbs free energy). The different phase behaviors upon CO2 absorption were discussed and well explained by the polarity change of components and the reaction products. A defined MPI value of tertiary amines was recommended to predict the immiscible type (MPI > 10.55 Kcal/mol), phase separation type (9.00 Kcal/mol < MPI < 10.08 Kcal/mol), and miscible type (MPI < 6.74 Kcal/mol). The electron density at the critical point of hydrogen bonds and interaction region indicators were employed to visually evaluate the influence of intramolecular and intermolecular hydrogen bonds on phase separation behaviors. The results show that the presence of excessive hydrogen bonds decreased the phase separation capacity. Furthermore, the relationship between the MPI, the Gibbs free energy of the proton transfer process and the phase separation time were explored. The increase of MPI caused by the tertiary amines can enhance the stability of the final product, delay the appearance of the phase separation peak and reach a maximum phase separation time of 230 min. Therefore, this study is significant for the screening and evaluation of efficient phase change absorbents with good potential for industrial applications in CO2 capture.

Utilizing the phase-field method to investigate liquid-liquid phase separation in the ternary system of water/ethanol/butylparaben

Small-molecule compounds targeted for drug development have frequently exhibited poor solubility in water, leading to instances of liquid-liquid phase separation (LLPS) during cooling crystallization and anti-solvent crystallization processes. Addressing strategies for managing crystallization processes involving LLPS has become a significant concern. Predicting changes in the structure and concentration of each separated phase over time would contribute to setting conditions and guiding process design to prevent oiling-out and achieve particles with desired morphology. In this study, we assessed the potential of the phase-field method to predict LLPS through simulations in a typical LLPS system, especially a ternary water/ethanol/butylparaben system. Consequently, the phase states in each zone (stable, metastable, and unstable) were determined to be thermodynamically valid. Additionally, the size of the spherical dispersed phase was confirmed to change in proportion to one-third of the time according to the Ostwald ripening rule. Furthermore, the qualitative analysis of factors influencing phase structure, local composition, delay time for phase separation in spinodal decomposition, and the localized LLPS during anti-solvent addition is also feasible. These findings suggest that the phase-field method holds potential as a tool to aid in the design of crystallization processes.

Selective lithium recovery from lithium precipitation mother liquor by using a diketone-based solvent

Lithium recovery from lithium precipitation mother liquor is an important point for improving lithium resource utilization efficiency. In this study, a modified β-diketone based organic solvent was developed. DBM was selected as extractant, which has the advantage of low cost compared to fluor-diketones. Organic phosphate TBP was used instead of traditional alkylphosphine oxide as co-extractant. The results show that TBP has the ability to inhabit the extraction of sodium so that it is positive for separation factor of lithium to sodium. Simultaneously, TBP plays the role of diluent, thus improving two-phase separation performance significantly. The phase separation time is only tens of seconds, which is much less than that of alkylphosphine oxide co-extraction system. Besides, low cost and low viscosity properties of TBP avoid the limitation of additive amount, which means that it has the industrial feasibility to improve the extraction performance by increasing TBP concentration. The developed extraction solvent has the combination sequence of H+ > > Li+ > > Na+. By using optimized solvent of 0.4 mol/L DBM and 1.2 mol/L TBP dissolved in sulfonated kerosene, single-stage lithium extraction rate is 99.96 % and separation factor of lithium to sodium reaches >160,000 at the O/A phase ratio of 1:1.

Stability Analysis of Pure Oil-Water Emulsion in Gravity-Based Separators

Abstract The purpose of this work is to investigate the stability of pure (emulsifier-free) oil-water emulsion in a gravity-based separator as a function of various parameters such as mixing speed, water volume concentration, temperature, and appearance. Only simple fluids (ExxsolTMD110 and distilled water) were used to form the dispersion in a separator of operational volume 200 ml and internal diameter of 60 mm. Data were gathered from a portable dispersion characterization rig where videos of liquid phase separation can be saved and scanned. The study considered a wide range of mixing speeds between 600 rpm and 2500 rpm, with elevated temperatures of 60 °C and 80 °C. Both types (oil-in-water (O/W) and water-in-oil (W/O)) of pure emulsion were studied. In addition, two volumetric water concentrations (WCs) were considered for each type to investigate its stability under the parameters tested (i.e., 25% and 50% WC for W/O emulsion and 75% and 90% WC for O/W emulsion). The stability of the emulsion was examined in terms of the separation profiles of the water and oil phase, oil/water mixture volume, initiation time of free phase separation and/or the final time of separation. Mixing speed was shown to drastically impact the stability of O/W emulsion, from a few minutes to over 4 h. Conversely, insignificant effects of mixing speed were seen for W/O emulsion as the emulsions overall separated in a few seconds. Although temperature accelerated the oil separation rates of 75% WC emulsions, it delayed the initiation time of water separation.

Correlating Aggregation Ability of Polymer Donors with Film Formation Kinetics for Organic Solar Cells with Improved Efficiency and Processability.

Film formation kinetics significantly impact molecular processability and power conversion efficiency (PCE) of organic solar cells. Here, two ternary random copolymerization polymers are reported, D18─N-p and D18─N-m, to modulate the aggregation ability of D18 by introducing trifluoromethyl-substituted pyridine unit at para- and meta-positions, respectively. The introduction of pyridine unit significantly reduces material aggregation ability and adjusts the interactions with acceptor L8-BO, thereby leading to largely changed film formation kinetics with earlier phase separation and longer film formation times, which enlarge fiber sizes in blend films and improve carrier generation and transport. As a result, D18─N-p with moderate aggregation ability delivers a high PCE of 18.82% with L8-BO, which is further improved to 19.45% via interface engineering. Despite the slightly inferior small area device performances, D18─N-m shows improved solubility, which inspires to adjust the ratio of meta-trifluoromethyl pyridine carefully and obtain a polymer donor D18─N-m-10 with good solubility in nonhalogenated solvent o-xylene. High PCEs of 13.07% and 12.43% in 1 cm2 device and 43 cm2 module fabricated with slot-die coating method are achieved based on D18─N-m-10:L8-BO blends. This work emphasizes film formation kinetics optimization in device fabrication via aggregation ability modulation of polymer donors for efficient devices.

SC crystals of porous PLA via thermally–induced phase separation: Effects of process conditions, solvent composition and nucleating agent

The formation of stereo-complex crystals (SC) in porous poly (lactic acid) (PLA) material is intricately linked with improving its comprehensive properties. In this work, the effects of process conditions, solvent composition and additional nucleating agent on SC crystals during the fabrication of porous PLA through thermally-induced phase separation method were studied. Crystallization behavior of SC crystals during the pore-forming process is systematically investigated, revealing that higher quenching temperature and longer quenching period facilitate the formation of SC crystals. Additionally, the addition of deionized water to the solvent effectively enhances SC crystals formation by reducing solution viscosity and prolonging the phase separation time. The highest crystallinity of SC crystals (XSC) can be achieved, reaching 30.6%, when the water content is controlled at 1.6%. Furthermore, the introduction of carbon nanotubes (CNTs) as a nucleating agent exhibits a pronounced effect on the formation of SC crystals. When incorporating a 3 wt% content of CNTs, XSC reaches its peak value at 37.7%. This work is helpful to provide reference for improving mechanical properties and heat resistance of porous PLA, thereby expanding its potential outdoor applications.

An improved preparation method of core-shell Al@Sn-Bi microspheres and its microstructure formation mechanism

This paper presents an improved method for achieving controllable preparation of the composition and size of the monotectic alloy core-shell structure microspheres. This advancement is expected to enhance the commercial application of monotectic alloy core-shell structure microspheres. By installing a heating device at the top of the drop tube in the pulsated orifice ejection method setup, we achieved in-situ heat treatment of falling droplets, resulting in the successful preparation of Al45(Sn42Bi58)55 core-shell structure microspheres. Furthermore, we investigated the formation mechanism of the Al@Sn-Bi core-shell structure. Nine sets of Al-Sn-Bi microspheres with varying in-situ heat treatment temperatures were prepared. Analysis via X-ray diffraction and transmission electron microscopy revealed that the microspheres consisted of Al-rich, Sn-rich, and Bi-rich phases, without any intermetallic compounds. Scanning electron microscopy results indicated that as the in-situ heat treatment temperature increased, the structure of the Al-Sn-Bi microspheres transitioned from irregular to regular core-shell configurations. This suggests that higher heat treatment temperatures prolong liquid phase separation time, leading to increased repetition of Marangoni motion within the droplet, Ostwald ripening of the minor phase droplets, and Soret effect of the matrix phase. However, at temperatures exceeding 700 °C, the solidification rate of alloy droplets decreased, causing the Al-rich phase core to deviate from the center and form a crescent structure due to Stokes motion.

Untangling the Molecular Interactions Underlying Intracellular Phase Separation Using Combined Global Sensitivity Analyses

Liquid-liquid phase separation is an intracellular mechanism by which molecules, usually proteins and RNAs, interact and then rapidly demix from the surrounding matrix to form membrane-less compartments necessary for cellular function. Occurring in both the cytoplasm and the nucleus, properties of the resulting droplets depend on a variety of characteristics specific to the molecules involved, such as valency, density, and diffusion within the crowded environment. Capturing these complexities in a biologically relevant model is difficult. To understand the nuanced dynamics between proteins and RNAs as they interact and form droplets, as well as the impact of these interactions on the resulting droplet properties, we turn to sensitivity analysis. In this work, we examine a previously published mathematical model of two RNA species competing for the same protein-binding partner. We use the combined analyses of Morris Method and Sobol’ sensitivity analysis to understand the impact of nine molecular parameters, subjected to three different initial conditions, on two observable LLPS outputs: the time of phase separation and the composition of the droplet field. Morris Method is a screening method capable of highlighting the most important parameters impacting a given output, while the variance-based Sobol’ analysis can quantify both the importance of a given parameter, as well as the other model parameters it interacts with, to produce the observed phenomena. Combining these two techniques allows Morris Method to identify the most important dynamics and circumvent the large computational expense associated with Sobol’, which then provides more nuanced information about parameter relationships. Together, the results of these combined methodologies highlight the complicated protein-RNA relationships underlying both the time of phase separation and the composition of the droplet field. Sobol’ sensitivity analysis reveals that observed spatial and temporal dynamics are due, at least in part, to high-level interactions between multiple (3+) parameters. Ultimately, this work discourages using a single measurement to extrapolate the value of any single rate or parameter value, while simultaneously establishing a framework in which to analyze and assess the impact of these small-scale molecular interactions on large-scale droplet properties.

The Physicochemical Basis for the Production of Rapeseed Oil Fatty Acid Esters in a Plug Flow Reactor

This article describes the results of a comprehensive comparative study of the production of fatty acid ethyl esters (FAEEs) for use as biodiesel in perfect mixing reactors (PMRs) and plug flow reactors (PFRs). The products obtained on a laboratory scale at all stages of the separation and purification of the FAEE phase were analyzed using the FTIR, XRF and GC-MS methods. We compared distillation methods for the separation of stoichiometrically excessive ethanol from the reaction mixture. Neutralization methods with H2SO4 solution and carbonation with CO2 were applied for FAEE phase purification from the catalyst. Emulsions formed during the water flushing stage were analyzed via the optical microscopy method. The optimal conditions of stirring speed and temperature were selected to maintain a high level of FAEE–water phase contact area with minimum phase separation time. The efficiency of the carbonation method for catalyst neutralization in the FAEE phase has been proven, allowing us to consider this method as an alternative to the traditional acid neutralization method. According to the results of experimental studies, we have developed a new high-performance technological scheme for the production of fatty acid esters in PFRs. The synthesis of FAEEs in a stoichiometric excess of ethanol of about 1:50 allowed us to increase the reaction rate and productivity of the synthesis unit after the transition from a PMR to a PFR. The yield of the product amounted to 86.7%. The purified FAEE fraction complied with most EN14214 specifications.

Comparative study of Biodiesel Production from Ethanol and Babassu oil using Mechanical Agitation and Ultrasounds

Babassu oil is a vegetable oil extracted from the seeds of the babassu palm (Attalea speciosa), which grows in most areas of South America. Brazil is the world's largest exporter of ethanol; the advantages of this alcohol are concerned to its renewable origin and low toxicity. In this work ethyl esters of babassu oil were synthesized by alkaline catalysis in homogeneous medium. The experimental design was used as a tool for optimization of the transesterification reaction and also in identifying key factors influencing the conversion into ethyl esters. The transesterification reactions were performed using two methods - the traditional mechanical agitation and agitation promoted by ultrasound waves. The nuclear magnetic resonance spectroscopy was used to quantify the conversion of all reactions of transesterification. According to the model obtained for mechanical agitation, conversions above 99% are obtained when the stoichiometric ratio is set at 6:1, with 1.0% KOH, under stirring at 400 rpm, in 60 minutes. Alkaline transesterification assisted by ultrasound waves produced the best results with respect to time of reaction and phase separation of glycerin and ethyl esters. The experimental model showed that conversions above 99% can be obtained in 10 minutes after adjusting the other independent variables.

Tuning and optimization of two-phase absorbents (DEEA/AEEA/H2O) with hybrid phase splitter (n-butanol/DEEA) for several properties: Carbon capture, phase separation, physical properties

In this study, we examined the impacts of complete and partial substitution of DEEA with physical solvents (n-butanol) on the performance of AEEA/H2O absorption, regeneration, and phase separation. The higher hydrophobicity (log P) of n-butanol, as a phase splitter, expedites the separation process from the AEEA-CO2 product. Through additional refinement of the mass ratio between n-butanol and DEEA, it was observed that substituting a small portion of DEEA with n-butanol had negligible impact on the absorption capacity and enrichment of the enriched phase. However, it significantly reduced the phase separation time between the two solvent phases. Furthermore, an increase in n-butanol concentration can enhance cyclic loading. On the other hand, it reduces the production of AEEACOO−/DEEAH+, which is more stable compared with AEEACOO−/AEEAH+. Molecular dynamics simulations revealed that n-butanol can modulate the reduction of water molecules surrounding AEEA, creating a lower water molecule environment, which improves the absorption rate of the absorbent in the pre-absorption phase. The addition of a low concentration of n-butanol improves the initial absorption rate, phase separation performance, circulation capacity, and further reduces the regeneration energy of the absorption solution without compromising the CO2 loading and regeneration energy.

Interfacial behavior and extraction kinetics of phages in a salting-out extraction system of ammonium citrate and ethyl acetate

To fight the increasing emergence and spread of antimicrobial resistance, phages have regained much more interest as the potential substitute in recent years. Separation and purification of phages were developed by salting-out extraction (SOE) with advantages of simpleness, high efficiency, high yield and the easiness to scale-up over the traditional means. In this study, SOE system composed of ammonium citrate and ethyl acetate was used to investigate the partition behavior of phages, phase separation, and extraction kinetics. With the increase of phase volume ratio, the phage phiAB9 was progressively transferred from the bottom phase to the middle phase. Accordingly, the solubility and aggregation of the middle phase increased, and the color got darker. Furthermore, the phase inversion point was kept at phase volume ratio between 1.0 and 1.1, at which the phase separation time was the shortest. The extraction kinetics revealed that the partition behavior could be finished in 10 min without centrifugation. Finally, the SOE system was also viable alternatives for the isolation and purification of phage λ, phiKP1 and phiSM1. The mechanism of SOE process is very important for its application and scale up in phage separation.

The Influence of Physical Properties on the Membrane Morphology Formation during the Nonisothermal Thermally Induced Phase Separation Process.

The physical properties of a polymer solution that are composition- and/or temperature-dependent are among the most influential parameters to impact the dynamics and thermodynamics of the phase separation process and, as a result, the morphology formation. In this study, the impact of composition- and temperature-dependent density, heat capacity, and heat conductivity on the membrane structure formation during the thermally induced phase separation process of a high-viscosity polymer solution was investigated via coupling the Cahn-Hilliard equation for phase separation with the Fourier heat transfer equation. The variations of each physical property were also investigated in terms of different boundary conditions and initial solvent volume fractions. It was determined that the physical properties of the polymer solution have a noteworthy impact on the membrane morphology in terms of shorter phase separation time and droplet size. In addition, the influence of enthalpy of demixing in this case is critical because each physical property showed a nonhomogeneous pattern owing to the heat generation during phase separation, which in turn influenced the membrane morphology. Accordingly, it was determined that investigating spinodal decomposition without including heat transfer and the impact of physical properties on the morphology formation would lead to an inadequate understanding of the process, specifically in high-viscosity polymer solutions.

A green yttrium extraction system containing naphthenic acid, trioctyl/decylamine and isopropanol

Yttrium extraction usually produces waste water and suffers from difficulty in phase separation when using saponified naphthenic acid as the extractant. Herein, a non-saponified mixed extraction system containing naphthenic acid, trioctyl/decylamine and modifier was developed for yttrium extraction. Unlike the traditional saponified naphthenic acid system using long chain alcohol as the modifier, short chain alcohol of isopropanol was introduced into the extraction system for the first time. When using 20 vol% naphthenic acid, 40 vol% trioctyl/decylamine, 10 vol% sec-octyl alcohol and 25 vol% isopropanol diluted in 5 vol% n-hexane as extractant, a high yttrium extraction efficiency of above 60% could be obtained within a short phase separation time of ∼5 min. The yttrium separation from other rare earth elements could be achieved through two steps of LaCePrNdY/GdSmEuTbDyHoErTmLuYb grouping extraction followed by LaCePrNd/Y separation. Trioctyl/decylamine, sec-octyl alcohol and isopropanol showed the synergistic extraction effect with naphthenic acid, among which isopropanol was the strongest, followed by trioctyl/decylamine and sec-octyl alcohol. Trioctyl/decylamine could extract H+ produced from naphthenic acid, and isopropanol and/or sec-octyl alcohol could bond with naphthenic acid via hydrogen-bond interaction to prevent the formation of naphthenic acid dimers, leading to more coordination sites exposed for yttrium extraction. Furthermore, isopropanol and/or sec-octyl alcohol participated in the coordination in the extracted organic compound. The combination of the above three action had great contribution to the high extraction efficiency and the rapid phase separation. There was no waste water produced during extraction. Therefore, the proposed mixed system is a green and efficient system for yttrium extraction.

Comparison of Cyclic Irradiation Behavior of Tri-Butyl Phosphate / Tri-Iso-Amyl Phosphate-Dodecane System in Nitric Acid Medium

ABSTRACT The degradation behavior of gamma irradiated solution of 1.1 M tri-butyl phosphate (TBP) in n-dodecane (n-DD) and 1.1 M tri-iso-amyl phosphate (TiAP) in n-DD loaded with nitric acid and uranium were compared up to 5 cycles upon recycling of the degraded solvent after 80 kGy in each cycle. The solvent was recycled by stripping the loaded metal with dilute nitric acid followed by alkali wash using sodium carbonate after each cycle. Subsequently, the physico-chemical properties and the metal extraction – retention properties of the recycled solvent were measured. The recycled solvent was analyzed using gas chromatographic and FT-IR spectroscopic analysis. Among the physico-chemical properties the interfacial tension of the recycled solvent decreased drastically after three cycles of irradiation, but the variation in the measured phase separation time was not significant. But, the concentration of the extractant (TBP/TiAP) decreased significantly upon recycling. Though the formation of nitro compounds was obvious from FT-IR analysis, the metal retention by recycled organic phases were comparable after each cycle of irradiation.

Effect of temperature on mixing and separation of stirred liquid/liquid dispersions over a wide range of dispersed phase fractions

Drop size distributions and phase separation were determined in a batch stirred tank with water/paraffin oil using optical measurement techniques. Temperature was varied from 20 °C to 80 °C and dispersed phase fractions up to 0.7, resulting in a phase inversion from oil-in-water to water-in-oil emulsions. Higher temperatures only increase Sauter mean diameters by 9.9%, but reduce phase separation time up to 67.4%. Higher dispersed phase fractions lead to bigger drop sizes and longer separation time. The interplay between drop size distribution characteristics and the phase separation process is investigated in detail. The performance of an existing phase separation model which considers physical properties and the initial Sauter mean diameter was evaluated, showing quite satisfying predictive power. Its predictive power might be further increased by including more information about the whole drop size distribution in future studies.

Ligand Effect on Physicochemical Properties of Ionic Liquid.

In the solvent extraction process, the importance of an extractant (or ligand) and a diluent is inferred from their respective physicochemical properties. We have brought together all the recent results reported on the mixture of different extractants dissolved in a well-known ionic liquid diluent: 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([C4 mim][NTf2 ]) in the form of a review and aimed to emphasize the role of ligand polarity and structure on the physicochemical properties of an ionic liquid (IL) diluent. Some of the most important properties such as dynamic viscosity (η), absolute density ( ), energy of activation (Ea ), coefficient of thermal expansion (α), phase separation time (PST), refractive index (n), etc., have been discussed meticulously in the paper. The effect of ligand structure on the aggregation behaviour of IL phase and the physicochemical properties of gamma irradiated solvent phases containing different ligands and their solution with IL phase also have been deliberated in detail.

Observations and simulations for phase separation process of immiscible Fe50Sn50 alloy droplets placed on a chilling surface

Liquid phase separation and microstructure evolution mechanisms of immiscible Fe50Sn50 alloy droplets placed on a chilling surface have been investigated by both arc melting experiments and lattice-Boltzmann simulations. The pattern selection of phase-separated morphologies strongly depended on the sample diameter. With the reduction in sample size, phase separation time was shortened, two-layer macrosegregation morphologies first transformed into intermediate phase-separated morphologies and finally changed into a homogeneously dispersed microstructure. The farther away from the sample bottom the longer the phase separation time and the larger the Sn-rich phase. A heat transfer equation was proposed to analyze the temperature field characteristics of Fe50Sn50 alloy droplets placed on the surface of a water-cooled copper mold. Theoretical analyses revealed that the sample gradually cooled from the bottom to the top of the sample. There existed a relatively high temperature gradient of several hundred Kelvins per millimeter between the top and the bottom of the arc melted sample, which induced the occurrence of an extremely intense Marangoni convection. The smaller the sample size the larger the temperature gradient and the greater deviation-degree of Fe-rich zone in two-layer macrosegregation structure from the bottom of the sample. The simulated two-layer phase-separated morphology agreed well with the experimental observations. Numerical simulations demonstrated that the effect of Marangoni convection on the phase separation was significantly stronger than the Stokes motion, and Fe-rich globules with a larger density tended to move upward to form a Fe-rich zone deviating from the bottom of the sample.

Wiped film evaporator with a roller wiper and an internally mounted condenser for the recovery of TBP and n-DD from degraded PUREX solvent

Wiped Film Evaporator (WFE) is a promising choice for processing viscous and thermally labile compounds due to its short residence time, enhanced heat transfer rates, and a high fraction of distillate yield in a single pass. This article evaluates the viability of a WFE with a roller wiper and an internally mounted condenser to recover tri-butyl phosphate (TBP) and n-dodecane (n-DD) from degraded PUREX solvent by vacuum distillation. Degraded solvents derived from different sources were purified using a combination of primary cleanup by sodium carbonate scrubbing and secondary cleanup by vacuum distillation using the WFE. Primary cleanup could efficiently remove the acidic degradation products of TBP. However, the scrubbed solvents were not of acceptable quality due to their poor physical properties. Secondary cleanup by vacuum distillation notably improved the physical properties of the solvent. A detailed quality assessment of the recovered solvents in terms of density, viscosity, interfacial tension (IFT), and phase separation time (PST) ratio showed that all the solvents recovered were of acceptable quality. The highest PST ratio and lowest IFT of the recovered solvents were 1.36 and 8.6 mN m−1, respectively. The maximum solvent recovery, TBP recovery, and n-DD recovery obtained were 93.8%, 83.8%, and 99.8%, respectively.

Microstructure determined the gel properties of gelatin/dextran more than the macrophase separation

Hydrogels are important in foods. Although the hydrogel microstructure has been commonly reported, the effect of the microstructure before and after gelation on gel properties was rarely investigated. This work aims to explore the effects of micro- and macro-phase separation of type-A gelatin-dextran (GE A /DE) aqueous solutions on the rheological, texture, and hydration properties of GE A /DE hydrogels. Three types of phase separation microstructures at both pH 5.0 and 7.0, e.g., DE-in-GE A emulsion, bicontinuous microstructure, and GE A -in-DE emulsion, were designed by adding different DE concentrations. GE A /DE mixtures showed macro-stability at pH 5.0, but macroscopic phase separation at pH 7.0, in which the phase separation time increased with the increasing DE concentration. During cooling-gelation, microstructures of mixtures were almost unchanged at pH 5.0, but significantly changed at pH 7.0. Interestingly, the microstructure determined the gel properties of phase-separated gels more than the macrophase separation. Microstructures of continuous phase with the gelling ability, e.g., DE-in-GE A and bicontinuous phase, hardly changed the moduli ( G′ and G″ ) and hardness of GE A /DE mixed gels, while the microstructure of GE A -in-DE without the gelling ability for continuous phase greatly reduced the moduli and hardness. This might be due to the different GE A volume fractions in GE A /DE mixed gels with different microstructures, and the mixed gel strength decreased with decreasing GE A volume fractions. Water holding capacity and swelling ratio of GE A /DE mixed gels reduced with the increasing DE concentration. This work provides some new information on how microstructure and macro-stability affect the physical properties of mixed gels. Effect of microstructure of GE A /DE before and after gelation on G′ and G″ at pH 5.0 and 7.0. • Three microstructures were designed based on gelatin/dextran phase separation. • Microstructures of macro-stable gelatin/dextran at pH 5.0 unchanged after gelation. • Microstructure determined gel properties more than the macrophase separation. • GE A volume fraction in the mixed gel might explain the effect of microstructures. • The gel strength of gelatin/dextran decreased with decreasing GE A volume fraction.