Water Solubilization Research Articles

Anisotropic reversed micelles with fluorocarbon-hydrocarbon hybrid surfactants in supercritical CO2.

Previous work (M. Sagisaka, et al. Langmuir 31 (2015) 7479-7487), showed the most effective fluorocarbon (FC) and hydrocarbon (HC) chain lengths in the hybrid surfactants FCm-HCn (sodium 1-oxo-1-[4-(perfluoroalkyl)phenyl]alkane-2-sulfonates, where m = FC length and n = HC length) were m and n = 6 and 4 for water solubilization, whereas m 6 and n 6, or m 6 and n 5, were optimal chain lengths for reversed micelle elongation in supercritical CO2. To clarify why this difference of only a few methylene chain units is so effective at tuning the solubilizing power and reversed micelle morphology, nanostructures of water-in-CO2 (W/CO2) microemulsions were investigated by high-pressure small-angle neutron scattering (SANS) measurements at different water-to-surfactant molar ratios (W0) and surfactant concentrations. By modelling SANS profiles with cylindrical and ellipsoidal form factors, the FC6-HCn/W/CO2 microemulsions were found to increase in size with increasing W0 and surfactant concentration. Ellipsoidal cross-sectional radii of the FC6-HC4/W/CO2 microemulsion droplets increased linearly with W0, and finally reached ∼39 Å and ∼78 Å at W0 = 85 (close to the upper limit of solubilizing power). These systems appear to be the largest W/CO2 microemulsion droplets ever reported. The aqueous domains of FC6-HC6 rod-like reversed micelles increased in size by 3.5 times on increasing surfactant concentration from 35 mM to 50 mM: at 35 mM, FC6-HC5 formed rod-like reversed micelles 5.3 times larger than FC6-HC6. Interestingly, these results suggest that hybrid HC-chains partition into the microemulsion aqueous cores with the sulfonate headgroups, or at the W/CO2 interfaces, and so play important roles for tuning the W/CO2 interfacial curvature. The super-efficient W/CO2-type solubilizer FC6-HC4, and the rod-like reversed micelle forming surfactant FC6-HC5, represent the most successful cases of low fluorine content additives. These surfactants facilitate VOC-free, effective and energy-saving CO2 solvent systems for applications such as extraction, dyeing, dry cleaning, metal-plating, enhanced oil recovery and organic/inorganic or nanomaterial synthesis.

Enhanced Colloidal Stability of Various Gold Nanostructures Using a Multicoordinating Polymer Coating

We describe the effectiveness of a multicoordinating polymer coating to surface functionalize gold nanospheres, nanoshells, and nanorods and promote their steric stabilization in biological media. The polymer ligand synthesized via one-step nucleophilic addition reaction starting with poly(isobutylene-alt-maleic anhydride) precursor presents multiple lipoic acid groups for strong coordination on metal-rich surfaces and several hydrophilic motifs (e.g., zwitterion groups or short poly(ethylene glycol) (PEG) chains) to promote water solubilization. We show that nanocrystals ligated with this polymer are compact in size and exhibit excellent long-term colloidal stability over broad conditions. We compare the ability of zwitterion- and PEG-modified polymer ligands to shield the metal surfaces from sodium cyanide digestion, or resist the competitive removal by dithiothreitol (DTT). We find that polymers appended with either hydrophilic motif essentially eliminate DTT competition for surface binding, while nano...

IFT and friccohesity study of formulation, wetting, dewetting of liquid systems using oscosurvismeter

Interfacial tension (IFT, mN/m) of pepsin with water and aqueous FeCl3 solution at 20 to 63G were studied along with a mutual wettability of water and isobutyl alcohol (IBA) with sodium and ammonium acetates at 298.15K. The Gauss doses and four H atoms of CH3COONH4 have decreased the IFT contrary to CH3COONa. FeCl3 has catalysed interfacial activities of pepsin in aqueous solution with its manifold unfolding resulting a larger surface area (1/τ=cm2/mol). Internal structures and surface areas of pepsin with weaker cohesive forces were analysed with SEM and Survismeter on exposure of electromagnetic dose of 63G induced by 2.5A current. Dewetting of Azadirachta indica (neem) oil with 0.001 to 0.015mol/L aqueous cetyltrimethylammonium bromide (CTAB) solutions was studied for reducing size of oil globules from <70μm to <100nm. Friccohesity a fundamental physicochemical property as a function of cohesive forces and spreading or frictional forces has resolved a closely placed interaction mechanism of water+(melamine-formaldehyde-polyvinylpyrrolidone=MFP) polymer resin mixtures. The focus has been on interacting molecular activities of magnetic field+FeCl3 on pepsin unfolding, acetate salts and surfactants to estimate water and IBA mutual solubilization, friccohesity of aqueous MFP resin. Stabilizing effect of pi-conjugation with a less mutual solubilization of benzene with water as compared to cyclohexane has produced higher IFT values. EDTA>borax>ninhydrin for 0.02 to 0.03mol/kg and borax>EDTA>ninhydrin orders for 0.04 to 0.08mol/kg substantiate a role of O atom due to its placement in chosen molecules.

Aggregation behaviour and solubilization capability of mixed micellar systems formed by a gemini lipoamino acid and a non-ionic surfactant

In this work we carried out the physicochemical characterization of mixtures of a non-ionic surfactant and a gemini lipoamino acid one. The mixed systems were studied by surface tension measurements, fluorescence quenching and SAXS determinations. Both surfactants formed mixed micelles in different relationships and the properties of the mixtures were more similar to those of their major component. SAXS analysis showed that the micelles were triaxial ellipsoids, type core shell. The mixtures exhibited non-ideal behaviour, as indicated by critical micelle concentrations (CMC) lower than those of the individual surfactants, and negative interaction parameters, β.The mixed surfactant systems produced enhanced water solubilization of polycyclic aromatic hydrocarbons, viz, naphthalene, phenanthrene and pyrene, quantified in terms of the molar solubilization ratio and the micelle-water partition coefficient. Synergism due to the presence of both surfactants in the mixture was observed for the solubilization of naphthalene and phenanthrene, but not for pyrene. This difference in behaviour might be related to the CMC and structure of the surfactants, the polarity of the solutes, and their association constants with the micellar phase.

Effect of amphoteric surfactant on phase behavior of hydrocarbon-electrolyte-water system-an application in enhanced oil recovery

ABSTRACTThe different techniques such as enhanced oil recovery (EOR) and improved oil recovery (IOR) have been used to enhance oil production. The surfactant flooding is a tertiary oil recovery technique that has been widely used in oil field industry. A variety of surfactant chemicals have been used in which among them the amphoteric type, which has two groups of opposite charges, needs more investigation. In this work, we use cocamidopropyl betaine as an amphoteric surfactant that is used to investigate its influence on the aquifer + hydrocarbon system. The effects of surfactant concentration, salinity, and hydrocarbon type on the phase behavior of the various saline aqueous-hydrocarbon mixtures are investigated. Moreover, the surfactant flooding is carried out using a glass micromodel. Thus, to investigate the wettability, the contact angle is also measured for the present system that it is an influential factor in oil recovery. First, by increasing salinity from 0 wt% to 20 wt% in n-hexadecane, the phase change take placed so that a Winsor formation from type I to III and then to type II occurs. However, for n-heptane upon enhancing salinity, Winsor type III is transformed to type II so that hydrocarbon (oil) recovery increases and break through occurs with a delay. By increasing salinity, water solubilization parameter decreases for both hydrocarbon and by enhancing both surfactant concentration and salinity leads to reduce the contact angle. Thus, cocamidopropyl betaine works better for the longer hydrocarbon chain.In the micromodel flooding test upon formation of Winsor II, the recovery is higher and the break through takes place with a delay. However, for the case of Winsor I, the recovery is lower and the break through occurs earlier. Finally, one can conclude that the low concentration of amphoteric surfactants needs to use that plays an important role in chemical EOR and results a higher recovery in high salinity.

Formation of 1-Butyl-3-methylimidazolium Bis(2-ethyl-1-hexyl)sulfosuccinate Stabilized Water-in-1-Butyl-3-methylimidazolium Bis(trifluoromethanesulfonyl)imide Microemulsion and the Effects of Additives

A new strategy is proposed here to formulate a bis(2-ethyl-1-hexyl)sulfosuccinate (AOT−) stabilized water-in-ionic liquid microemulsion without any additives. Replacing the inorganic counter ion Na+ by the organic 1-butyl-3-methylimidazolium ([Bmim]+) ion greatly improves the solubility of AOT− in hydrophobic 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([Bmim]Tf2N) (IL) and favors the formation of water-in-IL (W/IL) microdroplets. The existence of the W/IL microdroplets has been confirmed by dynamic light scattering, Fourier transform infrared absorption spectroscopy and ultraviolet–visible absorption spectroscopy. Also, presented for the first time are the effects of salts and alcohols on the microstructure and water solubilization capacity of the ternary H2O/[Bmim]AOT/[Bmim]Tf2N system. For inorganic salts, larger concentrations of the salt and higher charge density of the cation result in smaller microdroplet size and weak water solubilization capacity. For 1-hexanol, a high concentration of this alcohol results in small microdroplet size but high water solubilization capacity. Analyses indicate that the salts compress the electric double layers of W/IL microemulsions, decrease the size of the microdroplets and consequently reduce the water solubilization capacity; the alcohol, however, facilitates the aggregation of AOT−, increases the number of W/IL microdroplets, and therefore improves the water solubilization capacity of the system.

Cover Picture: Water Solubilization of Fullerene Derivatives by β‐(1,3‐1,6)‐d‐Glucan and Their Photodynamic Activities toward Macrophages (Chem. Asian J. 10/2017)

Cover Picture: Water Solubilization of Fullerene Derivatives by β‐(1,3‐1,6)‐<scp>d</scp>‐Glucan and Their Photodynamic Activities toward Macrophages (Chem. Asian J. 10/2017)

Formation dynamics of reverse micelles and nanosized effects that accompany chemical reduction of silver nanoparticles in them

Dynamic light scattering has been employed to study the time evolution of a sodium bis(2-ethylhexyl) sulfosuccinate/isooctane/water/quercetin/AgNO3 system during the formation of reverse micelles (RMs), as well as water solubilization and formation of Ag nanoparticles (NPs) in them. It has been shown that physicochemical processes occurring in the reverse micellar system lead to the formation of light-scattering elements with average sizes of 0.67−2 nm (individual molecules of the surfactant and reductant), 2.5−4.5 nm (“dry” RMs) and 16−20 nm (RMs containing Ag NPs). The synthesis is accompanied by the formation of silver NPs with other sizes in an amount of less than 5%.

Water Solubilization of Fullerene Derivatives by β‐(1,3‐1,6)‐d‐Glucan and Their Photodynamic Activities toward Macrophages

Anionic and neutral fullerene derivatives were dissolved in water by using β-(1,3-1,6)-d-glucan (β-1,3-glucan) as a solubilizing agent. In the water-solubilized complexes, the concentrations of fullerene derivatives were ≈0.30 mm and the average particle sizes were ≈90 nm. The β-1,3-glucan-complexed fullerene derivative with a carboxylic acid was found to have higher photodynamic activity toward macrophages under visible-light irradiation (λ>610 nm) than other β-1,3-glucan-complexed fullerene derivatives. This result suggests that carboxylic acid moieties in the complex enhance the binding affinity with β-1,3-glucan receptors on the surface of macrophages when the β-1,3-glucan is recognized. In contrast, all β-1,3-glucan-complexed fullerene derivatives showed no photodynamic activity toward HeLa cells under the same conditions.

Enhanced stability and water solubilizing capacity of water-in-oil microemulsions based on protic ionic liquids.

In an attempt to increase the stability and water uptake capacity of water-in-oil (W/O) microemulsions, here we study the physicochemical behavior of a series of protic ionic liquid based water/oil microemulsions, wherein solute amounts of biocompatible tetramethylguanidinium cation-based ionic liquids (ILs) are added to the aqueous phase of water-in-oil (W/O) microemulsions. FTIR and time-resolved fluorescence measurements showed an increased water uptake in these reverse micellar droplets, compared to conventional W/O microemulsions of similar compositions. Dynamic light scattering and differential scanning calorimetric measurements suggested greater thermal stability of the droplets in presence of the ILs. NMR and FTIR measurements and ab initio calculations explained these findings by showing an extended hydrogen bonding network between interfacial water and protic IL ions and strong electrostatic associations between the surfactant headgroups and IL anions. Our results pave the way for potential applications of protic ionic liquids in emulsion and microemulsion science and technology.

Optimizing side chains for crystal growth from water: a case study of aromatic amide foldamers.

The growth of crystals of aromatic compounds from water much depends on the nature of the water solubilizing functions that they carry. Rationalizing crystallization from water, and structure elucidation, of aromatic molecular and supramolecular systems is of general value across various fields of chemistry. Taking helical aromatic foldamers as a test case, we have validated several short polar side chains as efficient substituents to provide both solubility in, and crystal growth ability from, water. New 8-amino-2-quinolinecarboxylic acids bearing charged or neutral aminomethyl, carboxymethyl, sulfonic acid, or bis(hydroxymethyl)-methoxy side chains in position 4 or 5, were prepared on a multi gram scale. Fmoc protection of the main chain amine and suitable protections of the side chains ensured compatibility with solid phase synthesis. One tetrameric and five octameric oligoamides displaying these side chains were synthesized and shown to be soluble in water. In all cases but one, crystals were obtained using the hanging drop method, thus validating the initial design principle to combine polarity and rigidity. The only case that resisted crystallization appeared to be due to exceedingly high water solubility endowed by eight sulfonic acid functions. The neutral side chain did provide crystal growth ability from water but contributed poorly to solubility.

A two-step synthetic strategy to obtain a water-soluble derivative of curcumin with improved antioxidant capacity and in vitro cytotoxicity in C6 glioma cells

A novel water-soluble derivative of curcumin (Cur-[G-2]-OH) was designed and synthesized from accessible raw materials in only two steps with an overall yield of 80%. The modification of curcumin phenol groups with second-generation polyester dendrons (dendronization) as a strategy to achieve an optimal hydrophilic/hydrophobic balance allows the complete water solubilization of the new curcumin derivative (5mg/ml) at room temperature. The therapeutic potential of Cur-[G-2]-OH was investigated in terms of antioxidant capacity, intracellular uptake and cytotoxicity in both rat glioblastoma cells and normal human dermal fibroblasts. Although the phenolic groups of curcumin were locked by dendronization, Cur-[G-2]-OH exhibited antioxidant capacity in water that was even higher than curcumin in dimethylsulfoxide (DMSO). This compound showed a steady cellular uptake contrasted with curcumin, which has a saturation capture at high concentrations. Combined with improved stability, this property seems to allow the intracellular accumulation of Cur-[G-2]-OH. Furthermore, the new compound exhibited increased cytotoxicity in rat C6 glioma cells in a time- and concentration-dependent manner, whereas in normal human fibroblasts, its IC50 value was >600μM versus the IC50 of curcumin found between 100 and 200μM. Surprisingly, Cur-[G-2]-OH drives cell death of C6 cells by a different mechanism of apoptosis triggered by curcumin. Together, these results suggest that curcumin dendronization could promote molecular and cellular mechanisms that are different from those induced by curcumin, presumably due to structural factors and not only for improved water solubility.

Synthesis and characterization of thin film nanocomposite membranes incorporated with surface functionalized Silicon nanoparticles for improved water vapor permeation performance

The present work demonstrates the fabrication of novel thin film nanocomposite membranes incorporating surface functionalized Silicon nanoparticles (average size 15–20nm) for removal of water vapor from nitrogen gas. Silicon nanoparticles were synthesized using the inductively coupled plasma (ICP) technique. The nanoparticles were dispersed in deionized water to introduce hydroxyl functional groups on the surface. The surface functionalization was confirmed by infrared spectroscopy. The effect of nano-Si concentration on the water vapor permeation properties of the TFN membranes was investigated in detail. The hydroxyl functional groups resulted in significant improvement of surface hydrophilicity and roughness of the nanocomposite membranes which in turn enhanced the water solubilization. The small size of nanoparticles permitted extensive interaction between the nanoparticles and the thin film polyamide layer. Increase in the nano-Si concentration resulted in improvement of water vapor permeance and selectivity till 0.5w/w%, above which the selectivity decreased because of the interference in interfacial polymerization reaction due to the dilution of aqueous phase monomer and high loading of nanoparticles. Water vapor permeance in excess of 2200GPU with vapor/N2 selectivity of 501 was obtained when the nano-Si loading was 0.5w/w%. The introduction of nano-Si in the polyamide membrane improved the stability of the nanocomposite membrane such that it slightly resisted the decrease in water vapor permeance with operating temperature.

Host–guest inclusion system of rhein with polyamine-modified β-cyclodextrins: characterization and cytotoxicity

We report the preparation of inclusion complexes between rhein and four polyamine-modified β-cyclodextrins, namely amino-β-cyclodextrins (NH2-βCD), ethylenediamine-β-cyclodextrins (EN-βCD), diethylenetriamine-β-cyclodextrins (DETA-βCD) and triethylenetetramine-β-cyclodextrins (TETA-βCD) using suspension method. The solution and solid state forms of the inclusion complexes of rhein with polyamine-β-cyclodextrins were characterized by multiple techniques. Additionally, saturated solution and MTT methods were implemented to assess the water solubilization and in vitro cytotoxicity of the inclusion complexes, respectively. The results suggested that rhein was encapsulated within the CD cavity to form a 1:1 host–guest inclusion complex. Notably, a significant enhancement of the water solubility and in vitro cytotoxicity of rhein was found in the form of inclusion complex with polyamine-β-cyclodextrin.

Dimensionless Equation of State to Predict Microemulsion Phase Behavior.

Prediction of microemulsion phase behavior for changing state variables is critical to formulation design of surfactant-oil-brine (SOB) systems. SOB systems find applications in various chemical and petroleum processes, including enhanced oil recovery. A dimensional equation-of-state (EoS) was recently presented by Ghosh and Johns1 that relied on estimation of the surfactant tail length and surface area. We give an algorithm for flash calculations for estimation of three-phase Winsor regions that is more robust, simpler, and noniterative by making the equations dimensionless so that estimates of tail length and surface area are no longer needed. We predict phase behavior as a function temperature, pressure, volume, salinity, oil type, oil-water ratio, and surfactant/alcohol concentration. The dimensionless EoS is based on coupling the HLD-NAC (Hydrophilic Lipophilic Difference-Net Average Curvature) equations with new relationships between optimum salinity and solubility. An updated HLD expression that includes pressure is also used to complete the state description. A significant advantage of the dimensionless form of the EoS over the dimensional version is that salinity scans are tuned based only on one parameter, the interfacial volume ratio. Further, stability conditions are developed in a simplified way to predict whether an overall compositions lies within the single, two-, or three-phase regions. Important new microemulsion relationships are also found, the most important of which is that optimum solubilization ratio is equal to the harmonic mean of the oil and water solubilization ratios in the type III region. Thus, only one experimental measurement is needed in the three-phase zone to estimate the optimum solubilization ratio, a result which can aid experimental design and improve estimates of optimum from noisy data. Predictions with changing state variables are illustrated by comparison to experimental data using standard diagrams including a new type of dimensionless fish plot. The results show that the optimum solubilization ratio and salinity using the tuned dimensionless EoS are within average errors of 2.44% and 1.17% of experimental values for the fluids examined. We then use the dimensionless equations and thermodynamic first-principles to derive the constant in Huh's equation for interfacial tension prediction.

Improved solubilization of multiwalled carbon nanotubes (MWCNTs) in water by surface functionalization withd-glucose andd-fructose

Carbon nanotubes (CNTs) are difficult to be dispersed into a polymer matrix. For effective reinforcement, the strong interfacial interaction between nanotubes and the matrix is essential to donate the efficient thermal transfer from the matrix to nanotubes. In this study, multiwalled carbon nanotubes (MWCNTs) were modified with glucose and fructose carbohydrates as biomolecules to obtain Gl-MWCNTs and Fr-MWCNTs. Good water solubilization of MWCNTs was obtained, and these hybrids were expected to be biocompatible. Functionalized MWCNTs were incorporated into a poly(amide–imide) (PAI) matrix-containing alanine through a simple ultrasonication-assisted solution blending procedure. Then, it was tried to compare the obtained nanocomposites morphologically and thermally to study the compatibility between PAI matrix with Gl-MWCNTs and Fr-MWCNTs. Surface morphology observations suggested strong interfacial adhesion between the functionalized MWCNTs and the PAI matrix. This leads to homogeneous distribution of nanotubes throughout the matrix. Significantly better thermal properties of PAI were achieved by introducing Gl-MWCNT into the PAI matrix than that was achieved by similar incorporation of Fr-MWCNTs.

The mixing behaviour of anionic and nonionic surfactant blends in aqueous environment correlates in fatty acid ester medium

Mixtures of dissimilar surfactants can have superior properties compared to those of the individual surfactant components involved, which provide impetus for research on interactions between surfactants. It was also demonstrated that a change in the composition of external phase promotes remarkable changes in interfacial properties of reverse micelles (RMs), which are crucial to understand the system in order to use them as nanoreactors. Hence, it should be achievable to explore the influence of non-ionic Tween-85 on the properties of anionic AOT based micelle as well as RMs in fatty acid esters [e.g., ethyl myristate (EM), ethyl palmitate (EP) and ethyl oleate (EO)]. A comprehensive micellization behavior is studied at different mixed compositions (XTween-85) by surface tension method. Non-ideal mixing behaviors along with synergistic interaction between the constituent surfactants in the mixed micelles are evidenced. Mixed micelles illustrate favorable micellization behavior in terms of thermodynamic parameters. Further, fatty acid ester medium-based mixed RM shows synergism in water solubilization capacity. Microstructures of these systems are investigated by conductance, DLS, and FTIR studies. The solvation and rotational relaxation dynamics using picosecond time-resolved emission spectroscopy (TRES) is used to investigate the effect of XTween-85 as well as chemical architecture of fatty acid esters for the first time on the excited state dynamics of fluorophore. The solvation dynamics is found to be faster with an increase in XTween-85 and the average solvation time follows the order, EO<EP<EM, which collaborates well with droplet size and abundance of bulk-like water. Anisotropy studies reveal a decrease in the rotational restriction on the probe for EO based RMs. It is reasonable that this work have the potential to serve as good biomimicry models to study various processes occurring in biological molecules embedded in biomembranes.

Formation of water soluble wavelength tunable InGaP and InP quantum dots

Quantum dots (Q-dots) have recently attracted interest for biological applications as efficient biomarkers. Operational wavelength and water solubility are core considerations in terms of the applicable to Q-dots in biology. However, operating wavelength control and PL loss during water solubilization are major drawbacks. Herein, high quality, wavelength tuneable, and water soluble InGaP and InP were prepared using a simple thermal synthesis. The results obtained showed that the decrease in quantum yield previously observed in lipidized quantum dots loss was greatly diminished using this approach, which resulted in excellent control of emission wavelength and enhanced PL intensity. Q-dot sizes were controlled using a two-step etching process that enabled size control, significantly improved PL intensities, and minimized the loss in PL intensity associated with lipidization.

Fluorescent quantum dot hydrophilization with PAMAM dendrimer

Polyamidoamine (PAMAM) dendrimers were used to produce CdSe core/multi-shell fluorescent quantum dots (QDs) which are colloidally stable in aqueous solutions. The size, charge, and optical properties of QDs functionalized with the 4th (G4) and 5th (G5) generation of PAMAM were compared with amphiphilic polymer-covered QDs and used as criteria for the evaluation of the suitability of both water solubilization methods. As revealed by dynamic and electrophoretic light scattering (DLS and ELS), the hydrodynamic sizes of the QDs varied from 30 to 65 nm depending on QD type and dendrimer generation, with all QDs displaying highly positive surface charges, i.e., zeta potentials of around +50 mV in water. PAMAM functionalization yielded stable core/multi-shell QDs with photoluminescence quantum yields (Φ) of up to 45 %. These dendrimer-covered QDs showed a smaller decrease in their Φ upon phase transfer compared with QDs made water soluble via encapsulation with amphiphilic brush polymer bearing polyoxyethylene/polyoxypropylene chains.

Poly-arginine conjugated triarylmethyl radical as intracellular spin label

Stable triarylmethyl radicals are ideal spin labels used for biomedical electron paramagnetic resonance applications. Previously reported structures exhibit polar charged functions for water solubilization preventing them from crossing the cell membrane. We report the synthesis of a triarylmethyl radical conjugated to poly-arginine peptide allowing intracellular delivery of the paramagnetic label.