Hydrophilic Balance Research Articles

Dynamic interfacial activity and dilational viscoelasticity of polyether demulsifiers at the oil/water interface

A series of polyether demulsifiers with different PO/EO mass ratios and initiators were synthesized. The dynamic interfacial tension curves and dilational interfacial viscoelasticity of these polyethers at different oil/water interfaces were examined using the drop shape analysis method. Dynamic interfacial tension curves indicate weak adsorption of polyether demulsifiers at the diesel/water interface and strong adsorption at the xylene/water interface. Meanwhile, BPF9915 possesses the maximal interfacial activity among these three polyethers at the xylene/water interface, which differs from the diesel/water interface. Therefore, the dynamic interfacial activity of polyethers is related to the oil phase component.The order of dilational modulus of BPF polyethers at the diesel/water interface is BPF9935 > BPF9925 > BPF9915, which is similar to the order of dynamic interfacial activity. However, because of the weak adsorption of BPF polyethers, the values of dilational elasticity of BPF polyethers are small. Although these polyethers reduce the interfacial tension of the xylene/water interface sharply, the values of dilation elasticity of these polyethers at the xylene/water interface are close to those at the diesel/water interface. Therefore, these adsorptive branchedpolyethers exhibit weak intermolecular interaction.At the crude oil/water interface, the addition of polyethers causes the decrease of dilational interfacial elasticity, indicating the destruction of the dense interfacial adsorption layer by the BPF polyether. In addition, a hydrophobic polyether has a better dynamic interfacial activity in the crude oil, thus replacing the interfacial activity materials more effectively from the crude oil/water interface. Furthermore, the essential influencing factor of dynamic interfacial activity is PO/EO mass ratios rather than initiators. The PO/EO mass ratios will change the hydrophile and lipophilic balance, which is very important for the interfacial adsorption of polyether demulsifiers.

Inhibitory effects of oat peptides on lipolysis: A physicochemical perspective

Studies on the control of lipid digestion by food-derived active substances have prioritized the direct inhibition of lipase, ignoring the influence of these substances on the stability of bile salt (BS)-stabilized oil emulsions, which are essential for the hydrolysis of triglycerides by lipase. This study aimed to demonstrate the inhibitory potential of oat peptides (OPs) on lipolysis due to lipase inhibition, in particular, the physicochemical destruction of BS-stabilized emulsions. OPs were characterized by an enterostatin-like X-Pro-Y-Pro-Arg terminal sequence, competitively and/or noncompetitively inhibited lipase, and even caused lipase conformational changes. Interestingly, OPs destabilized BS-stabilized emulsions by weakening the rheological cross-linking structure of the emulsions through competitive hydrophobic binding to BS. Further analysis revealed that the H-bond binding of OP to BS significantly destroyed the hydrophilic and lipophilic balance of BS by increasing the surface hydrophobicity. These findings provided novel insights into the action mechanism of bioactive peptides on lipid digestion.

Monoribbed‐Functionalized Macrobicyclic Iron(II) Complexes Decorated with Terminal Reactive and Vector Groups: Synthetic Strategy, Chemical Transformations and Structural Characterization

Comprehensive SummaryGeneral and straightforward synthetic strategy towards the iron(II) clathrochelates with functionalizing substituents in their apical capping and one of the three chelate ribbed fragments was developed. Their hexachloroclathrochelate precursors were prepared by the direct template condensation of dichloroglyoxime with a suitable boronic acid on the Fe2+ ion as a matrix and underwent a stepwise nucleophilic substitution with S2‐, N2‐ or O2‐bis‐nucleophiles, forming the alicyclic or aromatic N2‐, S2‐ or O2‐six‐membered fragments. Depending on the reaction conditions and precursor‐to‐dinucleophile molar ratios, iron(II) clathrochelates with one (S, O and N), two (S, O and N) or three (S and O) X2‐six‐membered ribbed substituent(s) were obtained. Their reactivity substantially decreases in a row: Cl6‐Cage > Cl4X2‐Cage (where X = S, O or, especially, N) > Cl2X4‐Cage (where X = S or O). The reactive monoribbed‐functionalized clathrochelates underwent further chemical transformations giving the target macrobicyclic complexes with terminal vector groups. As follows from the single crystal XRD data, their FeN6‐coordination polyhedra possess the geometry intermediate between a trigonal prism and a trigonal antiprism (φ = 21.3°—25.20°). Fe—N distances vary from 1.887(6) to 1.933(8) Å. Their 3D‐molecules, the hydrophobic–hydrophilic balance in which can be tuned using a ribbed functionalization, form in the crystals the intermolecular specific halogen bonds and/or hydrophobic interactions.

Efficient, biosafe and tissue adhesive hemostatic cotton gauze with controlled balance of hydrophilicity and hydrophobicity

Cotton gauze is a widely used topical hemostatic material for bleeding control, but its high blood absorption capacity tends to cause extra blood loss. Therefore, development of rapid hemostatic cotton gauze with less blood loss is of great significance. Here, we develop an efficient hemostatic cotton gauze whose surface is slightly modified with a catechol compound which features a flexible long hydrophobic alkyl chain terminated with a catechol group. Its hemostatic performance in animal injuries is superior to standard cotton gauze and Combat GauzeTM. Its biosafety is similar to cotton gauze and rebleeding hardly occurs when the gauze is removed. Here, we show its hemostatic capability is attributable to the rapid formation of big and thick primary erythrocyte clots, due to its effective controlling of blood movement through blocking effect from tissue adhesion by catechol, blood wicking in cotton, and the hydrophobic effect from long alkyl chains.

Development of biobased emulsions for postharvest citrus fruit preservation

Penicillium digitatum is the causal agent for citrus green mold which generates 90% of post-harvest losses in Mediterranean countries. The use of a green seaweed extract to fight this fungal pathogen could represent an ecofriendly alternative to chemical fungicides. We propose to formulate an aqueous extract from Ulva lactuca (8.3%) in an emulsion for the preventive treatment of oranges. New biobased emulsifiers, alkyl aconitates, were synthesized according to a green process and were characterized by their hydrophilic and lipophilic balance (HLB) and their critical micelle concentration (CMC). These mono-, di and tri-dodecyl aconitates (8%) were effective in stabilizing an oil-in-water emulsion including the natural U. lactuca extract. The viscosities of resulting emulsions helped to form a film on the orange surface. Several in vitro microbiological tests towards Penicillium digitatum showed interesting anti-fungal activities for the new ingredients, as well as for the resulting emulsions. In-vivo tests also confirmed that mono-, di- and tri-docedyl aconitates could contribute to limit the development of P. digitatum on peel surface. Thus, the compositions of two ecofriendly emulsions combining a natural extract and a biobased emulsifier seem adapted to improve oranges preservation.

Recyclable, Immobilized Transition‐Metal Photocatalysts

AbstractThe use of transition‐metal complexes as photocatalysts have allowed the performance of diverse organic transformations in an outstanding manner, characterized not only by high yields, TOF, and selectivity values, but also by modulating and providing access to novel molecular structures that, without them, would be difficult if not impossible. However, one of the biggest concerns regarding the use of these photocatalysts relies on the difficulties associated with their isolation from reaction media and reutilization once the chemical process ends. The above, besides contaminating reaction products and requiring out tedious purification processes, prompts the inevitable loss of the catalyst, directly affecting its recyclability. In addition, this situation results in negative outcomes from an economic and environmental perspective, since transition‐metal complexes are usually expensive materials, and their unsuccessful recovery could result in leakage into the environment. These drawbacks served as inspiration for the elaboration of the present review focused on the development of novel strategies developed during the last decade for the successful recovery of these species. The strategies summarized herein, whether for homogeneous or heterogeneous systems, are based on the use of thermotropic solvents, changes in the hydrophilic balance of the catalyst, the employment of polymers, copolymers, porous macromolecular structures, and inorganic nanostructures as support of these entities. Moreover, the use of organized and confining media, such as micelles and gels in this context, is also discussed. We hope that this review will motivate the search for new strategies to develop novel catalytic systems, understanding that high performance is based not only on yields but also on recyclability, sustainability, and responsibility to the environment.magnified image

Dextrin and polyurethane graft copolymers as drug carrier: Synthesis, characterization, drug release, biocompatibility and in-vitro toxicity

Chemical modification of dextrin with polyurethane as a graft has been synthesized for controlled drug release for longer time period by maintaining the hydrophobic–hydrophilic balance. Estimation of the degree of grafting is visualized from the integrated peak area in the NMR spectra. Particle nature of dextrin is converted into strip like morphology in polyurethane graft dextrin copolymers as obvious from atomic force microscopy. Drug release study of graft copolymers through in vitro studies indicates sustained drug release behavior as compared to pristine dextrin and specific interactions between polymer and drug have been verified through spectroscopic techniques. Biocompatibility of the graft copolymers has been revealed using cellular studies on cancerous HeLa cells through MTT assay and cell adhesion. Further, the cytotoxicity or the cell killing efficiency has been demonstrated resulting in significant cell mortality using the developed graft copolymers.

Pour point depressant: identification of critical wax content and model system to estimate performance in crude oil

This study investigates the performance as pour point depressant of 15 samples of modified poly(ethylene-co-vinyl acetate) 10 mol% (EVA10), by hydrolysis and esterification, using wax model systems with different wax contents. Moreover, the best additives were also applied to crude oil (pure and with wax added). Pour point, wax appearance temperature and morphology analyses were used. The correlation between copolymer structure and pour point showed that both the hydrophilic and hydrophobic balance and the architecture of the molecule influence the additive performance. For high wax contents, the hydrolyzed EVA10 presented the best performance at an optimal hydrolysis degree (around 5.0 mol%). Increasing the wax concentration hampered the additive’s action, and the most critical concentration of waxes was observed with an increase from 5 to 6 w/v% wax, when the additive was no longer effective for the systems containing more than 11 w/v% wax. Results from the crude oils with wax added showed how significant the n-alkanes are for the pour point relative to iso- and cycloalkanes, and suggest that it is feasible to use model systems spreadsheet to estimate the performance of the additives in crude oils containing similar wax content.

Plugged bifunctional periodic mesoporous organosilica as a high-performance solid phase microextraction coating for improving extraction efficiency of chlorophenols in different matrices

In this study, a sensitive solid phase microextraction (SPME) coating was developed based on two kinds of plugged and non-plugged bifunctional periodic mesoporous organosilicas (BFPMO) with ionic liquid and ethyl units. The extraction efficiency of all plugged and unplugged sorbents was investigated for the extraction of chlorophenols (CPs) in water and honey samples by emphasizing the effect of different physicochemical properties. The separation and determination of the CPs was performed by gas chromatography-mass spectrometry (GC-MS). The extraction results showed that plugged BFPMO coating exhibited outstanding enrichment ability for the extraction of CPs as model analytes with different polarities. This can be attributed to a valuable hydrophobic−hydrophilic balance in the mesochanels of the plugged BFPMO, which is the result of the combination of plug technology and bridged organic groups.Low limits of detection in the range of 5–70 ng L−1, wide linearity, and good reproducibility (RSD = 8.1–10.1 % for n = 6) under the optimized extraction conditions were achieved. Finally, the BFPMOs coated fiber was successfully used for determination of CPs in real water samples. The relative recoveries for the five CPs were in the range of 92.3–104.0 %, which proved the applicability of the method.

Absorption properties of monolithic poly (divinylbenzene-co-N-vinylpyrrolidone) over a wide range of monomer ratios

The hydrophilic-lipophilic balance (HLB) polymers are able to directly extract polar and non-polar analytes from the aqueous samples, making them very popular for analytical separation and SPE applications. However, the commonly used suspension polymerization method for preparing HLB polymers is only able to efficiently prepare HLB polymers with low or medium mol percentages of the hydrophilic monomer due to the hydrophilic monomer partitioning into the aqueous phase at higher concentrations. Thus, in this study a series of HLB polymers based on divinylbenzene (DVB) (hydrophobic) and N-vinylpyrrolidone (NVP) (hydrophilic) of widely varying hydrophilicities were prepared by the more robust monolith polymerization method. The monolith polymerization enabled the preparation of DVB-co-NVP polymer from low to high NVP percentages (0 mol% to 55 mol% NVP). The comparative adsorption and separation properties of the series of DVB-co-NVP polymer were assessed using three analytes of varying polarity: adenosine (log P = −1.5), caffeine (log P = −0.07) and p-toluidine (log P = 1.39). Interestingly, the highest binding capacity for binding polar analytes was observed for the monolith polymer prepared with the intermediate 30:70 feed ratio of NVP/DVB, due to an optimal balance of surface area and hydrophilicity. Whereas, for the separation of the non-polar analytes such as p-toluidine from polar analytes like caffeine or adenosine, the hydrophobic polymers containing the lower percentages of the polar monomer (20 mol% NVP) were superior.

A novel structural design of air cathodes expanding three-phase reaction interfaces for zinc-air batteries

Zinc-air batteries are considered as potential energy conversion systems. One of the main issues of zinc-air batteries is the low actual power density. However, the three-phase reaction interfaces are limited in 2D plane of conventional air cathodes, which limits the electrochemical kinetics and the commercialization of zinc-air batteries. Here, a novel structural design of air cathodes with multi current collectors and gradient hydrophobicity to improve the discharge power for zinc-air batteries is proposed. Based on non-noble metal catalysts, the three-phase reaction interfaces expand from 2D plane to 3D zone by the novel structural design, increasing the power density of the battery. The gradient distribution of hydrophobicity in the air cathode can be obtained in one step through the soaking-drying process. When the soaking-drying process reaches twice, the optimal performance is achieved due to the balance of hydrophilicity and hydrophobicity. The peak power density of 120 mW·cm−2 is achieved in the zinc-air battery with MnO2 as catalysts. After continuously discharging at 20 mA·cm−2 exceed 9 h, the electrochemical performance can be restored by replacing with a new metal anode and keeping the initial air cathode. This work illustrates that the novel structural design of air cathodes can effectively improve the power density of zinc-air batteries, which is beneficial to the application of zinc-air batteries in the fields of energy storage and conversion.

Surface Modification of Barium Sulfate Particles

In this study, surface modification of barium sulfate was investigated using several model molecules for chemical treatment: ethanesulfonic acid, butyric acid, trimethoxy(propyl) silane and phosphoric acid 2-hydroxyethyl methacrylate. Samples were characterized by FT-IR and TGA to check the capability of these model molecules to interact with BaSO4 surface. The results pointed out the presence of an organic layer around the surface after the chemical treatment even after several washings to remove all species in excess. Model molecules were grafted onto BaSO4 surface and grafted density was determined. It reveals that phosphoric acid and carboxylic acid are the best candidates for the modification of BaSO4 surface. Both can be used as anchoring groups to modify the hydrophilic balance of barium sulfate surface in order to avoid the formation of aggregates and to improve the compatibility of this filler within hydrophobic polymer matrix.

Development of non‐leaching antibacterial coatings through quaternary ammonium salts of styrene based copolymers

AbstractNon‐leaching antibacterial coatings through quaternary ammonium salts containing polymers were successfully produced in a facile way to provide infection resistant surfaces against multi drug resistant bacteria such as B. licheniformis. In order to do so, a series of random copolymers of styrene (S) and vinyl benzyl chloride (VBC) were synthesized by free radical polymerization technique and subsequently, VBC (V) was functionalized with N,N‐dimethylhexadecylamine to introduce quaternary ammonium (QA) salts in the backbone of the copolymers. The copolymers showed an excellent film forming ability, thereby providing an ultrathin coating on various substrates such as metal (stainless steel), glass, polyethylene and polystyrene, as observed by SEM.The coatings were found to be uniform, non leachable in aqueous medium and exhibit good adhesion to various substrates. The antibacterial and antibiofilm activity of the non‐leachable coating of random copolymers were screened against B. licheniformis. Among, the copolymer containing 75% quaternized VBC (75VSQA) having 16‐C long alkyl chain was found to show maximum antibacterial and antibiofilm activity owing to an appropriate hydrophobic /hydrophilic balance. Their non‐leachable antibacterial and antibiofim activity make these coatings suitable for many applications, e.g. marine paints, textile/hospital coatings etc.

Toward Passive Defrosting with Heterogeneous Coatings

A large amount of energy is lost in industrial active deicing. One problem is that water retention on the surface after ice melting decreases the overall heat-transfer coefficient by up to 20%. The Miljkovic group utilizes heterogeneous biphilic surfaces to enhance defrosting performance. They avoid water retention as the slush is rapidly drawn toward the hydrophilic regions before it completely melts.

Redox-Active Polymers Connecting Living Microbial Cells to an Extracellular Electrical Circuit.

Microbial electrochemical systems in which metabolic electrons in living microbes have been extracted to or injected from an extracellular electrical circuit have attracted considerable attention as environmentally-friendly energy conversion systems. Since general microbes cannot exchange electrons with extracellular solids, electron mediators are needed to connect living cells to an extracellular electrode. Although hydrophobic small molecules that can penetrate cell membranes are commonly used as electron mediators, they cannot be dissolved at high concentrations in aqueous media. The use of hydrophobic mediators in combination with small hydrophilic redox molecules can substantially increase the efficiency of the extracellular electron transfer process, but this method has side effects, in some cases, such as cytotoxicity and environmental pollution. In this Review, recently-developed redox-active polymers are highlighted as a new type of electron mediator that has less cytotoxicity than many conventional electron mediators. Owing to the design flexibility of polymer structures, important parameters that affect electron transport properties, such as redox potential, the balance of hydrophobicity and hydrophilicity, and electron conductivity, can be systematically regulated.

Stearoylcholine and oleoylcholine: Synthesis, physico-chemical characterization, nanoparticle formation, and toxicity studies

Surfactants are used frequently as a component of pharmaceutical products. Cationic surfactants used to the formation of cationic nanoparticles (NPs) those present enhanced cellular uptake. With this purpose, first cationic surfactants, Stearylcholine (SC), and Oleylcholine (OC) were synthesized and then their characterization such as critical micelle concentration (CMC), Krafft temperature, and hydrophilic lyophilic balance (HLB) were evaluated. Cationic solid lipid nanoparticles (SLNs) were prepared through the emulsification method. The particle size and Zeta potential (ZP) of SC-SLNs were 93 ± 0.1 nm and +38.3 mV. OC-SLNs showed the particle size of 718 ± 0.1 nm and ZP of +39.9 mV. Cytotoxicity studies of SLNs and synthesized materials were assessed on human normal HFFF-2 and A549 lung cancer cells. Resultant SLNs showed no cytotoxic effects on HFFF-2 cells. SLNs and synthetic materials showed toxic effects on A549 lung cancer cells.

Assessment of the Likelihood of Underground Coal Oxidation and Self-Ignition: A Review

Standard and alternative methods of assessing the likelihood of coal oxidation and self-ignition in the bed are analyzed. These methods are based on the change in the petrographic, physicomechanical, chemical, and thermal properties of the coal on oxidation. Most of the methods are unsuitable for identification of the initial stage of coal oxidation. The onset of self-heating may be better determined on the basis of the surface properties of the coal: in particular, the hydrophobic–hydrophilic balance and the sorptional properties of internal surfaces. The extraction, transportation, and analysis of the coal sample from the bed must prevent contact with the air.

Surface Activity of Alkoxy Ethoxyethyl β-d-Glucopyranosides.

Dioxyethene fragment (-(OCH2CH2)2-) was introduced into traditional alkyl β-d-glucopyranosides to ameliorate the water solubility, and eight nonionic surfactants, that is, alkoxy ethoxyethyl β-d-glucopyranosides with alkyl chain lengths (n = 6-16), were synthesized and characterized. Their hydrophilic and lipophilic balance number, water solubility, critical micelle concentration (cmc), γcmc, Γmax, and hygroscopic rate decreased with an increase in the alkyl chain length. Hexadecoxy ethoxyethyl β-d-glucopyranoside had no water solubility at 25 °C. Decoxy ethoxyethyl β-d-glucopyranoside had the best emulsifying property in the toluene/water and n-octane/water systems and the strongest foaming property, whereas dodecoxy ethoxyethyl β-d-glucopyranoside had the best emulsifying property in the rapeseed oil/water system. Such β-d-glucopyranosides (n = 6-12) exhibited excellent surface activity. In addition, for the binary mixture of alkoxy ethoxyethyl β-d-glucopyranosides (n = 8, 10, 12) and sodium dodecyl sulfate or cetyl trimethyl ammonium chloride, their cmc values were lower than the pure β-d-glucopyranosides, indicating that they had synergistic interactions. The fan focal conic textures of alkoxy ethoxyethyl β-d-glucopyranosides (n = 7-16) were observed during the cooling process under a polarizing optical microscope. Alkoxy ethoxyethyl β-d-glucopyranosides (n = 14, 16) had the related melting points and the clear points with differential scanning calorimetry. With β-d-glucopyranosides (n = 6-16) and n-butanol as the surfactant and cosurfactant, respectively, and with cyclohexane as the oil phase, the related microemulsion areas in their pseudoternary phase diagram system were investigated with the visual observation at 25 °C. Along with the slashing requirements of petroleum consumption, environmental protection, and green and sustainable development, nonionic sugar-based alkoxy ethoxyethyl β-d-glucopyranosides should be expected to have their potential practical application because of their strengthened hydrophilicity, improved water solubility, and enhanced surface activity.

Thermoresponsive starch-based particle-stabilized Pickering high internal phase emulsions as nutraceutical containers for controlled release

Pickering high internal phase emulsions (HIPEs) stabilized solely by bioderived starch-based particles hold potential for application in the food and pharmaceutical fields. This paper reports the use of a thermoresponsive 2-hydroxy-3-butoxypropyl starch (HBPS) particle as a representative natural biocompatible material for use as an effective stabilizer for HIPE formation. HBPS is synthesized by using butyl glycidyl ether as a hydrophobic reagent to change the hydrophobic–hydrophilic balance of starch, and then starch-based particles are fabricated by a simple nanoprecipitation procedure. The size of particles increased with an increase in temperature, and the particles are essentially monodisperse with a PDI of about 0.1 when the temperature was above 15 °C. These HBPS particles were subsequently used as an effective stabilizer to fabricate stable oil-in-water (o/w) Pickering HIPEs with an internal phase volume of 80% at different stabilizer concentrations. The results demonstrated that increasing the particle concentration is conducive to the formation of stable Pickering HIPEs with greater stiffnesses. In addition, the nutraceutical material (β-carotene) was encapsulated into HIPEs and in vitro release experiments revealed that the release in this system can be controlled by adjusting the temperature.

Emulsification and Performance Measurement of Bio-oil with Diesel

To overcome the drawbacks of pyrolytic bio-oil, such as high acidity, viscidity, corrosivity, oxygen content and low heating value, a novel method of emulsifying bio-oil with diesel was investigated in this study. The effects of various factors on the stability of emulsified oil were examined. The optimal emulsification conditions of diesel and bio-oil are by using an emulsifier (mixture of Span 80 and Tween 80) dosage of 6% by mass and co-emulsifier (2-octanol) dosage of 4% by the mass of emulsifier, hydrophile lipophilic balance value of 7, shear velocity of 15,000 rpm, emulsifying time of 5 min, and emulsifying temperature at 40 °C. The stability time of emulsified oil is up to 384 h under the above optimal conditions. Some fuel properties were also measured to characterize the emulsified oil. The results show that the density, viscosity, corrosivity and heating value of emulsified oil at the optimal conditions are close to those of diesel oil. In addition, the mechanism model for the emulsion of bio-oil and diesel was also proposed.