Understanding the factors that affect bubble dissolution under pressure is crucial for the pneumatic transport of dispersions. This study probes the kinetics of air dissolution, the air solubility at a given pressure, and the gas diffusion due to bubble dissolution to elucidate the molecular mechanisms of gas transport in liquid dispersions with varied structures and viscosities. We achieve our aims by using water-glycerol mixtures, silicone oils with different viscosities, surfactant solutions containing worm-like micelles and having different macroscopic viscosities, particle suspensions, and surfactant solutions capable of forming a condensed adsorption layer on the bubble surfaces at ambient conditions. The results show that the dissolution rate does not depend on the macroscopic viscosity for silicone oils and solutions containing worm-like micelles, indicating that gas diffusion occurs faster than the movement of big polymeric molecules and worm-like micelles. We could predict the experimentally determined diffusion coefficients by accounting for free volume in these media and using the equation for Knudsen diffusion. We show that one way to decrease the rate of bubble dissolution under pressure is to add surfactants, which can decrease the permeability of the adsorption layer formed on the bubble surface by forming a condensed adsorption layer.

Hydroxypropyl cellulose (HPC) is a non-digestible water-soluble polysaccharide used in various food, cosmetic, and pharmaceutical applications. In the current study, the aqueous solutions of six HPC grades, with molecular mass ranging from 40 to 870 kDa, were characterized with respect to their precipitation temperatures, interfacial tensions (IFTs), rheological properties and emulsifying and stabilization ability in palm (PO) and sunflower (SFO) oil emulsions. The main conclusions from the obtained results are as follows: (1) Emulsion drop size follows a master curve as a function of HPC concentration for all studied polymers, indicating that polymer molecular mass and solution viscosity have a secondary effect, while the primary effect is the fraction of surface-active molecules, estimated to be around 1–2% for all polymers. (2) Stable emulsions were obtained only with HPC polymers with Mw ≥ 400 kDa at concentrations approximately 3.5 times higher than the critical overlap concentration, c*. At PO concentrations beyond 40 wt. % or when the temperature was 25 °C, these emulsions appeared as highly viscous liquids or non-flowing gels. (3) HPC polymers with Mw < 90 kDa were unable to form stable emulsions, as the surface-active molecules cannot provide steric stabilization even at c ≳ 4–5 c*, resulting in drop creaming and coalescence during storage.

The rheological properties of disperse systems play a crucial role in the production of foods, cosmetics, and pharmaceuticals with desired characteristics. Emulsion viscosity can be increased through various methods, incl. increasing the oil volume fraction, incorporating rheological modifiers, or inducing partial coalescence between the droplets. It is well known that suspensions containing inorganic non-spherical particles often exhibit significantly higher viscosities when compared to those with spherical particles. The spontaneous drop self-shaping phenomenon in emulsions, first reported in detail by Denkov et al. (Nature, 2015, 528, 392–395), enables the formation of fluid and frozen lipid particles with regular non-spherical shapes, including platelets, rods and fibers. In this study, we utilize this approach to prepare emulsions containing non-spherical frozen particles of various shapes and investigate their rheological properties. The effects of oil volume fraction, surfactant type, initial drop size and polydispersity are investigated. The results reveal that non-flowing, gel-like samples can be prepared at ca. 11 vol% oil fraction when the emulsion contains polydisperse droplets which acquire non-spherical shapes upon cooling. For comparison, more than ca. 65 vol% oil is needed to obtain similar rheological characteristics in samples containing spherical particles. Additionally, we demonstrate that the optimal drop size for gel preparation is d32 ≈ 4–13 μm. The obtained results are explained mechanistically, and guiding principles are provided for preparing emulsions with increased viscosities using this new approach.

Mixtures of multiple surfactants that have superior performance to the individual components are highly sought-after commercially. Mixtures with a reduced Krafft point (TK) are particularly useful as they enable applications at lower temperatures. Such an example is the soap maker’s eutectic: the mixture of sodium laurate (NaL) and sodium oleate (NaOl). A true eutectic implies that the two surfactants do not mix in the solid state but mix readily in the micellar solution above TK, leading to a sharp TK depression at a specific composition. However, the NaL/NaOl mixture shows a broad TK depression of >15 °C at a NaOl weight fraction (wO) of about 0.5. Our tie-line analysis shows that pure NaL and NaOl do not coexist in the solid phase on either side of the TK minimum. X-ray analysis of the isolated solids with varying wO reveals that a unique intermediate compound (I.C.) forms in the solid state with a NaL-to-NaOl mole ratio of about 4/3. Below the TK minimum, NaL and the I.C. coexist in the solids for wO 0.5. Each pair of solids exhibits eutectic or monotectic solubility behavior, and the congruent I.C. melting point is so close to that of the eutectic point(s) that a broad TK minimum ensues. Thermal analysis and modeling via the freezing-point depression approach support the above interpretation. The fact that surfactants with other headgroups but the same blend of chain lengths do not exhibit similar depressed TK is a topic for further study.

Spontaneous bubble growths in liquids are usually triggered by rapid changes in pressure or temperature that can lead to liquid gas supersaturation. Here, we report alternative scenarios of the spontaneous growths of bubbles inside a high-saturation-vapor-pressure and high-air-solubility perfluorocarbon liquid (PP1) that were observed under ambient quiescent conditions. First, we investigate spontaneous bubble growth inside the single PP1 phase, which was left to evaporate freely. The bubble growth is explained by the difference in the PP1 vapor pressure inside the bubble and that above the freely evaporating PP1 interface. Next, we study the bubble growth inside the liquid PP1 covered with a layer of a second air-saturated immiscible liquid: low-air-solubility water or higher-air-solubility ethanol. In both cases, the bubble growth rates were accelerated, indicating mass transfer of air from the water or ethanol phases to the PP1 phase. The bubble growth rates significantly increase for bubbles trapped at the PP1–water or PP1–ethanol interfaces due to faster air diffusion through the thin PP1 liquid films separating the bubbles from the upper phases. Finally, we consider the case of bubbles inside millimeter-sized PP1 emulsion droplets in water or ethanol. The bubble growth inside the droplet leads to an increase in the PP1 droplet’s effective buoyancy and to the detachment of the droplets from the substrate. The observed bubble growth rate in the case of emulsion droplets was much faster for PP1 droplets in ethanol than for PP1 droplets in water (minutes vs hours). The underlying physical mechanism of the increase of bubble volumes is the spontaneous mass transfer of both air and PP1 vapor to the bubbles produced by a colloidal diffusion pump effect.

Hypothesis: The presence of hydrodynamic slip of water on smooth hydrophobic surfaces has been debated
intensely over the last decades. In recent experiments, the stronger bounce of free-rising bubbles from smooth
hydrophobic surfaces compared to smooth hydrophilic surfaces was interpreted as evidence for a significant
water slip on smooth hydrophobic surfaces.
Experiments: To examine the possible water-slip effect, we conduct well-controlled experiments comparing the
bouncing dynamics of millimeter-sized free-rising bubbles from smooth hydrophobic and hydrophilic surfaces.
The hydrophobic surfaces were graphite or Teflon, and the hydrophilic surfaces were glass or mica. To avoid
contamination, the experiments were conducted in pure water without any surface-active additives. Numerical
simulations were also used to compare the bounce of the bubble from a no-slip and free-slip walls.
Finding: Our experiments show that the free-rising bubbles in pure water bounce identically from the smooth
hydrophobic graphite or Teflon surfaces as from smooth hydrophilic mica or glass surfaces. The bubble bounce
from all four surfaces is in excellent agreement with the numerical simulation of a bubble bouncing from a flat,
no-slip wall. At the same time, numerical simulations for bubbles bouncing from a free-slip wall predict up to
two-fold stronger bouncing amplitudes. Our experiments and numerical simulations, including estimates of the
shear rates, confirm the no-slip boundary condition for water on smooth hydrophobic surfaces.

Background and aims
Nanotechnology provides the opportunity for construction of modern transport devices such as nanoparticles for a variety of applications in the field of medicine. A novel experimental protocol for the formation of saponin-cholesterol-phospholipid nanoparticles of vesicular structure has been developed and applied to prepare stable nanoparticles using escin or glycyrrhizin as saponins.
Methods
The methods for nanoparticle construction include a sonication at 90 °C of the initial mixture of components, followed by an additional sonication on the next day for incorporation of an additional amount of cholesterol, thus forming stable unilamellar vesicles. Tests and assays for cell viability, erythrocyte hemolysis, flow cytometry, and fluorescent microscopy analyses have been performed.
Results
By selecting appropriate component ratios, stable and safe particles were formulated with respect to the tested bio-cells. The prepared nanoparticles have mean diameter between 70 and 130 nm, depending on their composition. The versatility of these nanoparticles allows for the encapsulation of various molecules, either within the vesicle interior for water-soluble components or within the vesicle walls for hydrophobic components. The saponin particles formed after cholesterol post-addition (E3-M2) are stable and 100 % of the cells remain viable even after 10-times dilution of the initial particle suspension. These particles are successful included into isolated mouse macrophages.
Conclusions
Among the variety of generated nanoparticles, the E3-M2 particles demonstrated properties of safe and efficient devices for future vaccine design and antigen targeting to immune system.

Hypothesis
Solubilization is a fundamental process that underpins various technologies in the pharmaceutical and chemical industry. However, knowledge of the location, orientation and interactions of solubilized molecules in the micelles is still limited. We expect all-atom molecular dynamics simulations to improve the molecular-level understanding of solubilization and to enable its in silico prediction.
Methods
The solubilization of six drugs in intestinal mixed micelles composed of taurocholate and dioleoyl phosphatidylcholine was simulated by molecular dynamics in explicit water and measured experimentally by liquid chromatography. The location and orientation of the solubilized drugs were visualized by cumulative radial distribution functions and interactions were characterized by radial distribution function ratios and hydrogen bonding.
Findings
A new simulation-derived parameter was defined, which accounts for drug-micelle and drug-water interactions and correlates (R2 = 0.83) with the experimentally measured solubilization. Lipophilicity was found to govern the location of all drugs in the micelle (hydrophobic core, palisade layer or on the surface), while hydrogen bonding was crucial for orientation and solubilization of two of the molecules. The study demonstrates that explicit, hydrogen bond-forming water molecules are vital for accurate prediction of solubilization and provides a comprehensive framework for quantitative studies of drug location and orientation within the micelles.

The rheological response of surfactant solutions containing a mixture of anionic and zwitterionic surfactants, in the presence of shorter-chain cationic and nonionic co-surfactants and various counterions was studied experimentally and described theoretically by developing the model that accounts for the competitive adsorption of different monovalent and divalent counterions, as well as the inclusion of co-surfactants within the micelles. This model was used to predict the salt curve dependence of systems with various salt and co-surfactant concentrations and was tested against the experimentally measured salt curves. A good agreement was found between the experimental data and the proposed theoretical model. It was demonstrated that the adsorption energies of counterions on the micellar surfaces remain unchanged with the addition of co-surfactants. However, the conditions for micelle branching are significantly affected, particularly in the presence of divalent and trivalent counterions. The presence of co-surfactants reduces the number of adsorbed divalent ions, thereby diminishing their effect on micelle branching.

Emulsification experiments with four silicone oils, having viscosities ranging from 0.01 to 30 Pa.s, were conducted in two types of media: nearly Newtonian polyvinyl alcohol (PVA) solutions and non-Newtonian mixtures induced by worm-like micelles in solutions of sodium laureth sulfate and cocoamidopropyl betaine (BS) with NaCl. The increased viscosity of BS solutions upon the addition of NaCl did not significantly affect the drop size in the formed emulsions. In contrast, the increased viscosity of solutions with higher PVA concentrations significantly reduced the drop sizes for all silicone oils. A theoretical expression predicting the maximum drop size in both types of media (nearly Newtonian and non-Newtonian) was derived and validated against experimental data. The expression accounts for shear-thinning behavior in both the aqueous and oil phases. Interfacial stress dominates the breakage of less viscous oils, while viscous stress inside the breaking drop plays a leading role for more viscous oils. The formation of emulsions with similar sizes in non-Newtonian solutions of BS with different NaCl concentrations was explained by their strongly shear-thinning behavior, which leads to nearly similar viscosity at high shear rates, despite their zero-shear viscosities differing by more than two orders of magnitude.

Hypothesis
Polyglycerol esters of fatty acids are generated via the esterification of a polydisperse mixture of polyglycerol with naturally derived fatty acids. The polymerization process of polyglycerol results in the production of various oligomers, ranging from di-, tri-, and higher-order forms, which contribute to the complexity of final products. The combination of complementary experimental techniques and adequate theoretical interpretations can reveal the wide variety of their physicochemical properties.

Experiments
The colloid and interface properties of polyglyceryl mono-laurate, mono-stearate, mono-oleate, and a mixture of mono-caprylate and mono-caprate esters solutions were characterized by measurements of the electrolytic conductivity, static and dynamic surface tension, aggregate and micelle sizes and distributions, thin liquid film stability and stratification, and solubility in aqueous and in oil phases. The formation, stability, and bubble size distribution of foams generated from polyglycerol esters aqueous solutions were systematically investigated.

Findings
The low concentrations of double-tail molecules and fatty acids in polyglycerol esters affect considerably their micellar, aggregation, and vesicle formations in aqueous solutions. The theoretical data interpretation of polyglycerol esters isotherms and thin liquid films data provide information on the adsorption energies, excluded areas per molecule, interaction parameters of molecules at interfaces, surface electrostatic potential, and the size of micelles. Polyglyceryl mono-oleate exhibits spontaneous emulsification properties. Short chain length polyglycerol esters have excellent foaming ability but relatively low foam stability. The optimal weight fractions of the short-chain polyglyceryl esters and polyglyceryl mono-stearate mixtures with respect to good foaminess and foam stability upon Ostwald ripening are obtained. The reported physicochemical characterization of the water-soluble polyglycerol esters could be of interest to increase the range of their applicability in practice.

Superhydrophobic surfaces are expected to reduce drag on bluff bodies moving in water due to the introduction
of a thin air layer around the solid and the resulting partial slip boundary condition. The use of Leidenfrost vapor
layers, sustained on the surface of a heated metal body is a reliable method to estimate the maximum drag
reduction possible due to such air layers. In the past such an approach was used to estimate the drag reduction on
a free-falling heated sphere, in which case the form drag is the lead component of the drag force. Here, we extend
this approach to evaluate the effect of the thin gas layers on the hydrodynamic drag of free-falling streamlined
projectiles and towed model boats, where the form drag is minimal, and the skin friction drag is the lead
component of the drag force. By comparing the drag for streamlined bodies with and without sustained airlayers, we see only incremental drag reductions, for the sub-critical Reynolds number tested herein. The same
is true for towed model boats. These results hold both for superhydrophobic surface treatments and Leidenfrost
vapor layers. Thus, we concluded that for the investigated range of sub-critical Reynolds numbers, the skin
friction drag is less sensitive to the effect of the thin gas layers compared to the form drag. These novel findings
have important implications for the practical potential of energy savings using gas layers sustained on super
hydrophobic surfaces.

Lipids in human intestinal fluids (HIF) form various structures, resulting in phase separation in the form of a lipid fraction and a micellar aqueous fraction. Currently used fed state simulated intestinal fluids (SIF) lack phase separation, highlighting the need for a deeper understanding of the effect of these fractions on intestinal drug solubilization in HIF to improve simulation accuracy. In this study, duodenal fluids aspirated from 21 healthy volunteers in fasted, early fed, and late fed states were used to generate 7 HIF pools for each prandial state. The apparent solubility of seven lipophilic model drugs was measured across these HIF pools, differentiating between the micellar fraction and the total sample (including both micellar and lipid fractions). The solubilizing capacities of these fluids were analyzed in relation to their composition, including total lipids, bile salts, phospholipids, total cholesterol, pH, and total protein. The solubility data generated in this work demonstrated that current fed state SIF effectively predicted the average solubility in the micellar fraction of HIF but failed to discern the considerable variability between HIF pools. Furthermore, the inclusion of a lipid fraction significantly enhanced the solubility of fed state HIF pools, resulting on average in a 13.9-fold increase in solubilizing capacity across the seven model compounds. Although the average composition of the fluids was consistent with previous studies, substantial variability was observed in micellar lipid concentrations, despite relatively stable total lipid concentrations. This variability is critical, as evidenced by the strong correlations between the solubilizing capacity of the micellar fraction and its micellar lipid concentrations. Additionally, this study identified that fluctuations in bile salt concentrations and pH contributed to the observed variability in micellar lipid concentration. In summary, the influence of the lipid fraction on solubility was 2-fold: it enhanced the solubility of lipophilic drugs in the total fluid, and contributed to the variability in the solubilizing capacity of the micellar fraction.

Micelles formed by bile salts in aqueous solution are important for the solubilization of hydrophobic molecules in the gastrointestinal tract. The molecular level information about the mechanism and driving forces for primary-to-secondary micelle transition is still missing. In the current study, the micelle formation of 50 mM solutions of taurodeoxycholate (TDC) is studied by atomistic molecular dynamics simulations. It is shown that primary micelles with an aggregation number of 8-10 emerge and persist within the first 50 ns. Then, they coalesce to form secondary micelles with an aggregation number of 19 molecules. This transition is governed by hydrophobic interactions, which significantly decrease the solvent-accessible surface area per molecule in the secondary micelles. The addition of monomers of the sodium salt of fatty acids (FAs), as agents aiding hydrophobic drug delivery, to secondary TDC micelles results in the co-existence of mixed FA-TDC and pure FA micelles. The studied saturated FAs, with chain lengths of C14:0 and C18:0, are incorporated into the micelle core, whereas TDC molecules position themselves around the FAs, forming a shell on the micelle surface. In contrast, the tails of the C18:1 unsaturated fatty acid mix homogeneously with TDC molecules throughout the entire micelle volume. The latter creates a very suitable medium for hosting hydrophobic molecules in the micelles containing unsaturated fatty acids.

The primary objective of this study is to determine the similarities and differences in the surface, film, and foam properties of alkyl sucrose esters (SEs) with high monoester content (≥ 70 %) and polyoxyethylene alkyl ethers (Brijs) with a high number of ethoxy groups (≥ 20) in their head group. Experiments were conducted using surfactant molecules with alkyl chain lengths of 12, 16, and 18 carbon atoms at concentrations between 0.01 and 1 wt%, within a temperature range of 25 °C to 60 °C.
The lag time for surfactant adsorption increased with surfactant chain length, decreased with temperature, and significantly decreased with surfactant concentration for both types of studied surfactants. However, increasing the chain length from 12 to 18 carbon atoms led to a 10-fold increase in lag time for Brijs and more than a 600-fold increase for SEs. This effect rendered longer-chain SEs incapable of forming voluminous foam in Bartsch test and led to pronounced coalescence between the bubbles after their separation from the sparger in the foam rise method, resulting in foams with very large bubbles, which exhibited lower stability. The utilization of a Kenwood mixer for foam generation provided sufficient time for longer-chain SE molecules to adsorb on the bubble surfaces and to produce voluminous foams with small bubbles, which remained stable even at 60 °C. In contrast, foams generated from Brijs solutions are very unstable at 60 °C. The long-standing stability of SEs foam was attributed to the formation of mixed mono- and diesters adsorption layers on the bubble surfaces.

The present study explores the cleaning efficacy of a set of nonionic surfactants (linear ethoxylated alcohol, secondary ethoxylated alcohols with 5, 7, and 9 ethoxy groups, glycoside surfactants, polyglycerol surfactants, and an ethoxylated sorbitan monolaurate) combined with cationic biocides—alkyl quaternary ammonium salts. A simple hard surface cleaning methodology was applied, which was shown to discriminate well between poor and good cleaning formulations. In addition to cleaning efficacy, surface aesthetics such as gloss and haze were evaluated together to assess surface streaking caused by a residual surfactant layer. The haziness determination turned out to be the key feature revealing the complex cleaning performance of multi-component products.

Amorphous solid dispersions enhance the dissolution and oral bioavailability of poorly water-soluble drugs. However, the link between polymer properties and formulation performance has not been fully clarified yet. We studied the effect of hydroxypropyl cellulose (HPC) polymers molecular weight (Mw) on the storage stability, dissolution kinetics and supersaturation stability of spray-dried amorphous glibenclamide (GLB) formulations. The solid-state stability of amorphous GLB during storage was significantly enhanced by both the 40 kDa (HPC-SSL) and 84 kDa (HPC-L) polymers, regardless of Mw differences. In contrast, HPC-SSL maintained significantly higher aqueous drug concentrations during dissolution, compared to HPC-L (its higher Mw analogue). Dedicated dissolution experiments, in situ optical microscopy and solid-state characterization revealed that aqueous drug concentrations were determined by the interplay between crystallization inhibition, drug ionization, wetting and solubilization effects: (1) HPC prevents surface nucleation, hence inhibiting crystallization, (2) intestinal colloids (bile salts and phospholipids) increase supersaturated drug concentrations via wetting and solubilization effects and (3) pH and drug ionization severely impact the degree of supersaturation. The better performance of the lower Mw HPC-SSL was due to its superior inhibition of surface crystallization during dissolution. These insights into the molecular mechanisms of dissolution and crystallization of amorphous solids provide foundation for rational formulation development.

Sucrose esters (SEs), derived from sucrose and fatty acids, are biodegradable and non-toxic surfactants increasingly favored as substitutes for petrochemically synthesized ones in food, cosmetics, and pharmaceuticals. SEs provide versatile hydrophilic–lipophilic properties, determined by the degree of sucrose esterification ranging from one to eight. The length of the fatty acid residues further influences the phase behavior of SEs, allowing creation of tailored formulations for specific applications. This review provides insights about our current understanding of the SEs phase behavior, their aggregation in aqueous and oily solutions, and its correlation with formulation outcomes. Furthermore, an overview of recent studies investigating SEs in various colloidal systems, including emulsions, foams, oleogels, and others, is provided. Novel concepts are discussed alongside future research directions, emphasizing the SEs potential as sustainable, functional ingredients.

Medium- to long-chain alkanes can form upon cooling intermediate phases between isotropic liquid and solid crystalline, called rotator phases, where relative freedom of the molecules to rotate about their long axis is combined with long range translational order. Rotator phases are well documented experimentally but the mechanism of their formation at the molecular level is still not fully explained. In a previous work, we have shown that molecular dynamics simulations can produce rotator phases upon cooling of hexadecane [S. Iliev et al., J. Col. Int. Sci., 2023, 638, 743]. The aim of the current work is to develop a procedure to identify the specific ordered phase obtained in the simulations. The influence of the cooling rate on the freezing process of hexadecane (bulk and surfactant-interfaced to water) is tested as well. Several parameters are combined to quantify the degree of ordering and the type of phase in the studied systems. These are the tilt angle of the molecules with respect to the crystallite plane, the radial distribution function of the centre of mass of the molecules in the crystallite, the percentage of the gauche torsion angles in the molecules, the angle of the second principal axis of each molecule with respect to the x axis of the coordinate system, and estimates from Voronoi analysis. The results show that the systems form a rotator phase, which transitions gradually towards the thermodynamically most stable triclinic crystal, and the transformation progresses to different extent depending on the system. The influence of the cooling rate is related only to the size of the largest crystallite formed, the other parameters of the freezing process remain unaffected. The work also presents a robust procedure for obtaining and identifying different types of ordered phases in alkane-containing systems with thoroughly tested computational protocol and a comprehensive set of structural analyses. Several key characteristics are advanced, compared to previous research [Ryckaert et al., Mol. Phys., 1989, 67, 957; Wentzel et al., J. Chem. Phys. 2011, 134, 224504], namely, a new methodology is proposed to compute the unit cell deformation parameter and azimuthal angle from MD simulation trajectories of the freezing process in alkane-containing systems. The suggested structural analysis, which is independent of the coordinate system, is applicable to any linear-chain system with polycrystalline structure.

Hypothesis: Aqueous solutions of long-chain water-soluble sucrose ester surfactants exhibit non-trivial response to temperature variations, revealing a peak in viscosity around 40–50 ◦C. While previous investigations have explored the structures within sucrose stearate systems at various constant temperatures, a comprehensive understanding of the entire temperature dependence and the underlying molecular factors, contributing to this phenomenon is currently missing. Experiments: Temperature dependent properties and supramolecular structures formed in aqueous solutions of commercial sucrose palmitate were examined using SAXS/WAXS, DSC, optical microscopy, rheological measurements, NMR, and cryo-TEM. Findings: The underlying mechanism governing this unusual behavior is revealed and is shown to relate to the mono- to di-esters ratio in the solutions. Solutions primarily containing sucrose monoesters (monoesters molecules ≳ 98% of all surfactant molecules) exhibit behavior typical of nonionic surfactants, with minimal changes with temperature. In contrast, the coexistence of mono- and di-esters results in the formation of discrete monodisperse diester particles and a network of partially fused diester particles at low temperature. As the temperature approaches the diesters’ melting point, wormlike mixed micelles form, causing a viscosity peak. The height of this peak increases significantly with the diester concentration. Further temperature increase leads to fluidization of surfactant tails and formation of branched micelles, while excess diester molecules phase separate into distinct droplets.