Search

Aqueous film-forming foam is being phased out due to the environmental impacts of fluorinated surfactants contained in the firefighting foams. To develop an environmentally friendly firefighting foam, it is important to understand the factors controlling the firefighting performance of surfactants. Fuel transport through foam has been considered as a dominant mechanism for foam collapse. Therefore, the impact of fuels (heptane, octane and trimethylbenzene (TMB)) on surfactant microstructure was studied for three different types of surfactants (Capstone, Glucopon, and siloxane) that have applications in firefighting foam. Multiple techniques were used to identify the microstructure and interfacial properties of surfactants with and without exposure to liquid fuel. The ignition time of fuel vapor through foam and solubility of fuel through liquid surfactant solution were measured as well. This work shows fuel solubility has an impact on the surfactant microstructure and interfacial properties. In addition, fuel solubility and vapor pressure affect the ignition time of fuel vapors. [ABSTRACT FROM AUTHOR]

Per- and polyfluoroalkyl substances (PFAS) are being increasingly measured in water and wastewater due to emerging toxicity concerns and strict regulatory limits. Previous studies have filtered water samples to remove suspended solids before PFAS analysis. However, filtration may introduce negative bias to measured PFAS concentrations. Using a well-controlled syringe pump assembly, we evaluated retention of six perfluoroalkyl carboxylates, three perfluoroalkyl sulfonates, one fluorotelomer sulfonate, and two perfluorooctane sulfonamides by glass-fiber, glass-fiber cellulose acetate, nylon, polyethersulfone, polypropylene, polyvinylidene fluoride/ difluoride, and surfactant-free cellulose acetate filters. The impacts of water quality and operational parameters were also investigated for select filter types. We found that PFAS were retained on all filters, with the glass-fiber cellulose acetate filters demonstrating the lowest retention. For all filters, PFAS retention was linearly related to chain length and hydrophobicity above certain thresholds (i.e., log D higher than 1.5). Importantly, more PFAS were retained at low filtrate volumes, and ~ 30 mL filtrate was required before the retention efficiencies stabilized. Solution pH only affected the retention of perfluorooctane sulfonamides. Pore size (i.e., 0.20, 0.45, 0.70 µm), filtration rate (i.e., 0.5, 1.0 mL min−1), and PFAS concentration (i.e., 10, 100 µg L−1), did not exert major influences on PFAS retention. The presence of dissolved organic matter improved PFAS permeation. Based on the reported results, filtration introduces bias and is not recommended for sample pretreatment. [ABSTRACT FROM AUTHOR]

Aqueous film-forming foams (AFFFs) are the primary source of toxic perfluoroalkyl and polyfluoroalkyl substances (PFAS) in wastewater. Thus, it is urgent to develop a facile and fast method for identifying fluorosurfactants in commercially available AFFFs. In this work, fluorine nuclear magnetic resonance (19F NMR) spectroscopy was optimized to measure AFFFs directly with the extra addition of 5% D2O as the locking reagent, and high-quality spectra could be acquired within 4 min (0.1% fluorosurfactant content). Recovery experiments demonstrated that the use of different AFFFs had no marked influence on the quantitative analysis of fluorosurfactants. Such method works with low-field NMR spectroscopy (1.4 T) as well. Two-dimensional (2D) 19F COSY NMR was used to make signal assignments for different fluorosurfactant derivatives. The optimized 19F NMR could quantify the commercially available fluorosurfactants in different AFFFs, identify them being in either the perfluorooctane sulfonate (PFOS) or fluorotelomer sulfonic acid (FTS) categories, and distinguish the head-group of PFOS and FTS derivatives, which exhibits great potentials in the developments of relevant commercial detections. [ABSTRACT FROM AUTHOR]

Perfluorocarbon-encapsulated silica nanoparticles possess attractive features such as biological inertness and favorable colloidal properties for bioimaging with fluorine magnetic resonance imaging (19F MRI). Herein, a series of elliptic shaped silica nanoparticles with perfluorocarbon liquid perfluoro-15-crown-5 ether as core (PFCE@SiO2) were synthesized using fluorinated surfactants N-(perfluorononylmethyl)-N,N,N-trimethylammonium chloride (C10-TAC) and N-(perfluoroheptylmethyl)-N,N,N-trimethylammonium chloride (C8-TAC). The nanoparticles are characterized to obtain elliptic core-shell structures. PFCE@ SiO2 showed strong 19F NMR signals of the encapsulated PFCE, indicating the potential as a highly sensitive 19F MRI probe. These elliptic PFCE@SiO2 nanoparticles provide a new option of 19F MRI probe with a morphology different from conventional nanospheres. [ABSTRACT FROM AUTHOR]

To make the most of the unique properties of nanomaterials, and to bridge the gap between fundamental and applied research, controlled, green, cheap and energy efficient syntheses of nanoparticles are required. In this respect, room and low temperature surfactant-free colloidal syntheses of nanoparticles obtained in low viscosity and low boiling point solvents, without additives or nature-derived extracts, are promising to develop more active (electro)catalysts. Recently, a room temperature synthesis of surfactant-free gold nanoparticles has been documented (Chem. Mater. 2023, 35, 5, 2173) that requires only water, a base such as NaOH, an alcohol and HAuCl4. Unfortunately, the syntheses of nanomaterials are often sensitive to multiple parameters and it is well acknowledged that reproducibility is a general challenge in the chemical sciences, where the synthesis of nanomaterials is no exception. Here, we investigate the effect of the water conductivity and solvent grade on the surfactant-free low temperature (ca. 30 °C) synthesis of colloidal gold nanoparticles obtained in alkaline mixtures of ethanol and water. The synthesis can be performed with relatively low-grade ethanol but requires high purity water. The importance of water with low conductivity is also stressed for syntheses where ethylene glycol and glycerol are used as source of reducing agents. The results of this study over 100 samples pave the way to greener, more controlled and scalable syntheses of surfactant-free gold nanomaterials. [ABSTRACT FROM AUTHOR]

Microdroplet-based fluidic systems have the advantages of small size, short diffusion time, and no cross-contamination; consequently, droplets often provide a fast and precise reaction environment as well as an analytical environment for individual molecules. In order to handle diverse reactions, we developed a method to create organic single-micron droplets (S-MDs) smaller than 5 μm in diameter dispersed in silicone oil without surfactant. The S-MD generation microflow device consists of a mother droplet (MoD) generator and a tapered separation channel featuring multiple side channels. The tapered channel enhanced the shear forces to form tails from the MoDs, causing them to break up. Surface treatment with the fluoropolymer CYTOP protected PDMS fluid devices from organic fluids. The tailing separation of methanol droplets was accomplished without the use of surfactants. The generation of tiny organic droplets may offer new insights into chemical separation and help study the scaling effects of various chemical reactions. [ABSTRACT FROM AUTHOR]

Heterocyclic‐based cationic surfactants with dodecyl tail group bridged to the head group either via aromatic ether [3‐(4‐dodecyloxybenzyl)‐1‐methyl‐imidazolium bromide (Ar‐I) and 4‐(4‐dodecyloxybenzyl)‐4‐methyl‐morpholinium bromide (Ar‐M)] or via aliphatic ether [3‐(2‐dodecyloxyethyl)‐1‐methyl imidazolium bromide (Al‐I) and 4‐(2‐dodecyloxyethyl)‐4‐methyl morpholinium bromide (Al‐M)] were synthesized and characterized using different spectral techniques. For the synthesis of Ar‐I and Ar‐M, 4‐hydroxybenzoic acid was esterified initially, followed by O‐alkylation, reduction, bromination and finally quaternization either with 1‐methylimidazole or with 4‐methylmorpholine. For the synthesis of aliphatic analogues (Al‐I and Al‐M), ethylene glycol was initially alkylated, followed by tosylation, bromination and quaternization either with 1‐methylimidazole or with 4‐methylmorpholine. Synthesized surfactants were evaluated for surface and self‐assembly properties. Impact of the presence or absence of phenyl ring bridging the polar head and nonpolar tail of the surfactant and also type of heterocyclic moiety in the head group region on micellization and surface properties such as wetting, foaming and emulsification was studied. Surfactants with the bridged aromatic ether moiety were observed to display lower critical micelle concentration than those with the bridged aliphatic ether moiety irrespective of type of heterocyclic molecule in the head group region. Foam volume and stability of the aromatic ether‐bridged surfactant were observed to be superior to their corresponding aliphatic analogs. Similar trend was observed in stabilizing the emulsion. However, aromatic ether‐bridged surfactant depicted poor wetting ability compared to their aliphatic analog. Aliphatic ether bridged surfactant showed higher aggregation number compared to their aromatic counterparts, but depicted similar micellar core polarity. [ABSTRACT FROM AUTHOR]

Electrolyte engineering is a fascinating choice to improve the performance of Li‐rich layered oxide cathodes (LRLO) for high‐energy lithium‐ion batteries. However, many existing electrolyte designs and adjustment principles tend to overlook the unique challenges posed by LRLO, particularly the nucleophilic attack. Here, we introduce an electrolyte modification by locally replacing carbonate solvents in traditional electrolytes with a fluoro‐ether. By benefit of the decomposition of fluoro‐ether under nucleophilic O‐related attacks, which delivers an excellent passivation layer with LiF and polymers, possessing rigidity and flexibility on the LRLO surface. More importantly, the fluoro‐ether acts as "sutures", ensuring the integrity and stability of both interfacial and bulk structures, which contributed to suppressing severe polarization and enhancing the cycling capacity retention from 39 % to 78 % after 300 cycles for the 4.8 V‐class LRLO. This key electrolyte strategy with comprehensive analysis, provides new insights into addressing nucleophilic challenge for high‐energy anionic redox related cathode systems. [ABSTRACT FROM AUTHOR]

[Display omitted] Aqueous solutions of mixtures of hydrogenated and perfluorinated ionic surfactants are known to display anomalous aggregation behavior due to the mutual phobicity between hydrogenated and perfluorinated chains. Despite all efforts, different experimental limitations prevented so far a definite interpretation of the existing experimental results: both intermicellar and intramicellar segregation remain acceptable possibilities. The potential for segregation of mixtures of fluorinated and hydrogenated ionic surfactants in water was assessed using atomistic molecular dynamics simulations. Aqueous mixtures of hydrogenated and perfluorinated ionic surfactants were studied: mixtures of anionic surfactants (sodium dodecylsulfate (SDS) + sodium perfluoro-octanoate (SPFO)) and catanionic surfactants (decyltrimethylammonium bromide (DeTAB) + SPFO) were simulated. The mixture of anionic surfactants, SDS + SPFO, exhibits clear intramicellar segregation between fluorinated and hydrogenated chains, displaying hydrogenous-rich and fluorous-rich regions. Compartmentalized micelles are thus clearly formed. The simulation results also suggest the possibility of intermicellar segregation. Conversely, catanionic mixtures of DeTAB and SPFO in water solution assemble into a large oblate structure, containing all available molecules in the simulation box, resembling a double layer membrane or a vesicle wall. In this case mixing between fluorinated and hydrogenated surfactants is dictated by charge alternation. [ABSTRACT FROM AUTHOR]

Droplet‐based microfluidics represents a disruptive technology in the field of chemistry and biology through the generation and manipulation of sub‐microlitre droplets. To avoid droplet coalescence, fluoropolymer‐based surfactants are commonly used to reduce the interfacial tension between two immiscible phases to stabilize droplet interfaces. However, the conventional preparation of fluorosurfactants involves multiple steps of conjugation reactions between fluorinated and hydrophilic segments to form multiple‐block copolymers. In addition, synthesis of customized surfactants with tailored properties is challenging due to the complex synthesis process. Here, we report a highly efficient synthetic method that utilizes living radical polymerization (LRP) to produce fluorosurfactants with tailored functionalities. Compared to the commercialized surfactant, our surfactants outperform in thermal cycling for polymerase chain reaction (PCR) testing, and exhibit exceptional biocompatibility for cell and yeast culturing in a double‐emulsion system. This breakthrough synthetic approach has the potential to revolutionize the field of droplet‐based microfluidics by enabling the development of novel designs that generate droplets with superior stability and functionality for a wide range of applications. [ABSTRACT FROM AUTHOR]

The evaporation of particle‐free silver ink droplets on heated substrates directly impacts the morphology of the resultant silver particles and electrically conductive inkjet‐printed films. In this work, COMSOL Multiphysics simulations of the droplet evaporation process are used to help explain the fluidic processes responsible for the experimental observations. The results show that the silver particle morphology depends on its location within the evaporating droplet where large particles (3 to 5 µm) accumulate at the center and smaller ones (1 to 2 µm) in the area beyond the central region. The smallest particles (≈500 nm) are near the contact line. Without the fluoro‐surfactant FS‐31, an inner ring with 3 µm particles also appears within the evaporating droplet. The large particles at the central region originate from the fluid near the droplet's apex due to the accumulation of polyacrylamide in the concentrated ethylene glycol solvent near the flow‐abundant apex. Furthermore, the capillary flow along the fluid–air interface transports silver ions and particles throughout the droplet, causing the larger particles to fall onto the substrate at the central vortex, forming the inner ring. The simulations also demonstrate that the evaporating droplet heterogeneously accumulates ethylene glycol in a sandhill formation at the bottom center. [ABSTRACT FROM AUTHOR]

Fluorosurfactants are the key ingredients in the formulations of aqueous film-forming foams (AFFFs) for extinguishing flammable liquids, thus developing high-efficient and low-toxic fluorosurfactants is desirable in AFFFs application. Herein, a series of hyperbranched polymeric fluorosurfactants (HPFs) were successfully synthesized through sequentially modifying hyperbranched polyethylenimine (PEI) with the hydrophilic poly(ethylene glycol) (PEG) chains and the hydrophobic C6/C4-based perfluoroalkyl chains, which were verified by FTIR, 1H- and 19F-NMR. The surface tensions of all the HPFs in water were measured, and the corresponding physicochemical parameters were interpreted. It was found that the surface activities of HPFs could be tuned through adjusting the ratio of PEG to perfluoroalkyl chains, the length of perfluoroalkyl chains, the molecular weight of PEI core, but not the PEG chain length. In the binary mixture of HPFs with the commercial small molecule fluorosurfactant Capstone™ 1157 (C1157), a strong synergism led to the elevation of surface activity, which was attributed to the efficient encapsulation of C1157 guests by the compact hyperbranched HPFs as the hosts. The utilization of HPF/C1157 as fluorosurfactant ingredients in AFFF formulations could realize much higher fire-extinguishing efficiency towards flammable oils than the control AFFFs prepared from the polymeric Capstone™ 1460 or the neat C1157. [ABSTRACT FROM AUTHOR]

HRMS: I m i / I z i [M + NH SB 4 sb ] SP + sp calcd for C SB 14 sb H SB 15 sb ClFN SB 2 sb O SB 4 sb S SP + sp : 361.0420; found: 361.0416. HRMS: I m i / I z i [M + NH SB 4 sb ] SP + sp calcd for C SB 15 sb H SB 15 sb FN SB 3 sb O SB 4 sb S SP + sp : 352.0762; found: 352.0759. HRMS: I m i / I z i [M + NH SB 4 sb ] SP + sp calcd for C SB 15 sb H SB 15 sb FN SB 3 sb O SB 4 sb S SP + sp : 352.0762; found: 352.0765. HRMS: I m i / I z i [M + NH SB 4 sb ] SP + sp calcd for C SB 11 sb H SB 12 sb FN SB 2 sb O SB 4 sb S SB 2 sb SP + sp : 319.0217; found: 319.0221. [Extracted from the article]

It is of great significance to study the stability of foams in the petroleum industry. Therefore, the stability mechanism of Span 20, the fluorinated surfactant FCO‐80 and their mixture FS in a CO2 oil‐based foam system were studied by molecular simulation. The sandwich model of CO2 oil‐based foam was constructed to reveal the stability of the foam system from the microscopic perspective. The result shows that under the synergistic effect of Span 20 and FCO‐80, the oil–CO2 distance of the FS foam system and the coordination number of oil molecules are larger than those of Span 20 and FCO‐80 foam system. In FS foam system, the diffusion coefficients of CO2 molecules are small, and the surface tension is reduced, which can improve the stability of foam. The results can supplement previous experimental results on the stability of oil‐based foam. [ABSTRACT FROM AUTHOR]

Per- and polyfluoroalkyl substances (PFAS) pose a major health and environmental problem. Methods are needed to ensure that PFAS are not released into the environment during their use or disposal. Alumina-based catalysts have been used for the abatement of small perfluorocarbons, e.g. tetrafluoromethane and perfluoropropane, emitted during the silicon etching process. Here, an alumina-based catalyst was tested to determine if these catalysts may facilitate the destruction of gas-phase PFAS. The catalyst was challenged with two nonionic surfactants with eight fluorinated carbons, 8:2 fluorotelomer alcohol and N-Ethyl-N-(2-hydroxyethyl)perfluorooctylsulfonamide. The catalyst helped decrease the temperatures needed for the destruction of the parent PFAS relative to a thermal-only treatment. Temperatures of 200°C were sufficient to destroy the parent PFAS using the catalyst, although a significant number of fluorinated products of incomplete destruction (PIDs) were observed. The PIDs were no longer observed by about 500°C with catalyst treatment. Alumina-based catalysts are a promising PFAS pollution control technology that could eliminate both perfluorocarbons and longer chain PFAS from gas streams. Implications: The release of per- and polyfluoroalkyl substances (PFAS) into the atmosphere can cause problems for human health and the environment. It is critical to reduce and eliminate PFAS emissions from potential sources, such as manufacturers, destruction technologies, and fluoropolymer processing and application sites. Here, an alumina-based catalyst was used to eliminate the emissions of two gas-phase PFAS with eight fully fluorinated carbons. No PFAS were observed in the emissions when the catalyst was at 500°C, lowering the energy requirements for PFAS destruction. This shows that alumina-based catalysts are a promising area for research for PFAS pollution controls and the elimination of PFAS emissions into the atmosphere. [ABSTRACT FROM AUTHOR]

A novel synthetic procedure for the functionalisation of styrenic cross-linked polymers with perfluorinated acyl chains has been reported. The effective significant grafting of the fluorinated moieties is supported by {1H}-13C and {19F}-13C NMR characterisations. This kind of polymer appears promising as catalytic support for a variety of reactions requiring a highly lipophilic catalyst. Indeed, the improved lipophilicity of the materials resulted in enhanced catalytic properties of the corresponding sulfonic materials in the reaction of esterification of a solution in a vegetable oil of stearic acid with methanol. [ABSTRACT FROM AUTHOR]

Cardiovascular disease (CVD) poses the leading threats to human health and life, and their occurrence and severity are associated with exposure to environmental pollutants. Per- and polyfluoroalkyl substances (PFAS), a group of widely used industrial chemicals, are characterized by persistence, long-distance migration, bioaccumulation, and toxicity. Some PFAS, particularly perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA) and perfluorohexanesulfonic acid (PFHxS), have been banned, leaving only legacy exposure to the environment and human body, while a number of novel PFAS alternatives have emerged and raised concerns, such as polyfluoroalkyl ether sulfonic and carboxylic acid (PFESA and PFECA) and sodium p-perfluorous nonenoxybenzene sulfonate (OBS). Overall, this review systematically elucidated the adverse cardiovascular (CV) effects of legacy and emerging PFAS, emphasized the dose/concentration-dependent, time-dependent, carbon chain length-dependent, sex-specific, and coexposure effects, and discussed the underlying mechanisms and possible prevention and treatment. Extensive epidemiological and laboratory evidence suggests that accumulated serum levels of legacy PFAS possibly contribute to an increased risk of CVD and its subclinical course, such as cardiac toxicity, vascular disorder, hypertension, and dyslipidemia. The underlying biological mechanisms may include oxidative stress, signaling pathway disturbance, lipid metabolism disturbance, and so on. Various emerging alternatives to PFAS also play increasingly prominent toxic roles in CV outcomes that are milder, similar to, or more severe than legacy PFAS. Future research is recommended to conduct more in-depth CV toxicity assessments of legacy and emerging PFAS and explore more effective surveillance, prevention, and treatment strategies, accordingly. [ABSTRACT FROM AUTHOR]

Perfluorooctane sulfonate (PFOS) is gaining widespread attention as a persistent organic pollutant with multiple mechanisms of toxicity. In this study, PFOS at different concentrations and different exposure times was used to evaluate the multiple toxicities on intact planarian Dugesia japonica. The proliferation of neoblasts, apoptosis, DNA damage and the expression levels of neuronal genes and the major genes of the Wnt pathway were effectively studied. The results demonstrated that the balance between proliferation and apoptosis of intact planarian cells was disrupted after PFOS exposure, which in turn affected tissue homeostasis and differentiation. PFOS exposure led to increased DNA damage and altered neuronal gene expression. In addition, PFOS exposure could down-regulate the expression of Wnt pathway genes, but the inhibition of the Wnt pathway by PFOS was time- and concentration-dependent. These findings suggest that PFOS has multiple toxic effects on planarians and may interfere with cell proliferation and neurodevelopment by affecting the key gene expression in the Wnt pathway, providing estimable information on the neurodevelopmental toxicity and ecotoxicity of PFOS toxicity in aquatic animals and environments. [ABSTRACT FROM AUTHOR]

Surfactants containing fluorocarbon chains have been increasingly studied because they self-assemble into a variety of microscopic and mesoscopic domains and tend to form highly ordered patterns at the air/water interface; these patterns are clearly different from those formed by their hydrocarbon analogs. Focusing on the fluorinated surfactants possessing unique physical characteristics, this review describes the relationship between the line tension and dipole interaction, which is the comprehensive principle governing the pattern formation of two-dimensional self-assemblies. This review further discusses several key experimental and analytical techniques that are useful for characterizing the shape, size, correlation, and viscoelasticity of hierarchical self-assemblies on water surfaces. Finally, several biomedical applications, including biomimetic surface coating, multimodal contrast agents in medical diagnostics, and controlled delivery of gases (O2 and NO) for oxygenation and antimicrobial effects, are introduced to highlight how the unique physicochemical properties of fluorinated self-assemblies can be applied in materials science. Fluorinated surfactants: X-ray scattering reveals unique structures Fluorinated surfactants, long organic chains bearing bulky fluorine atoms, are increasingly being used in biomedical applications, thanks to improvements in nanoscale x-ray techniques. Fluorinated surfactants have low toxicity and form stable emulsions for drug delivery thanks to their water-repelling nature. Motomu Tanaka from Kyoto University in Japan and colleagues review how fluorinated surfactants form unique structures when compressed into monomolecular films on water surfaces, including microstripes, flat nanodiscs, and hexagonal arrays. Small-angle x-ray scattering of these structures has now revealed the interfacial forces that drive stable pattern formation in these films. Researchers have used this approach to produce longer-lasting 'microbubble' contrast agents for ultrasound imaging coated with fluorinated surfactants. Other applications include biomimetic surfaces used for studying the adhesive functions of cells, and magnetic resonance imaging contrast agents that incorporate iron oxide nanoparticles. Due to their unique physical characteristics, surfactants containing fluorocarbon chains form hierarchical patterns of two-dimensional mesoscopic/microscopic self-assemblies on the surface of water. This review describes the overarching physical mechanism, the competitive interplay of line tension and dipole interaction and discusses several key experimental and analytical techniques characterizing the shape, size, correlation, and viscoelasticity of mesoscopic/microscopic self-assemblies on water, which is often non-trivial. Some of the recent biomedical applications, including biomimetic surface coating, contrast agents in multimodal imaging, and controlled delivery, are introduced to highlight how the unique physicochemical properties of fluorinated self-assemblies can be applied in materials science. [ABSTRACT FROM AUTHOR]

This Minireview discusses recent developments in research on the interfacial phenomena of fluorinated amphiphiles, with a focus on applications that exploit the unique and manifold interfacial properties associated with these amphiphiles. Most notably, fluorinated amphiphiles form stable aggregates with often distinctly different morphologies compared to their nonfluorinated counterparts. Consequently, fluorinated surfactants have found wide use in high‐performance applications such as microfluidic‐assisted screening. Additionally, their fluorine‐specific behaviour at solid/liquid interfaces, such as the formation of superhydrophobic coatings after deposition on surfaces, will be discussed. As fluorinated surfactants and perfluorinated materials in general pose potential environmental threats, recent developments in their remediation based on their adsorption onto fluorinated surfaces will be evaluated. [ABSTRACT FROM AUTHOR]

The formation heats for a number of gemini fluorocarbon surfactants have been estimated using density functional theory (DFT), the values of air/water interface formation energies (IFE) have been compared. It is shown that the fluorocarbon surfactants can efficiently reduce the surface tension of the air/water interface. One of the representatives of the surfactants, possessing the highest IFE value (in absolute value), has been prepared and its critical micelle concentration and the corresponding surface tension have been experimentally determined. [ABSTRACT FROM AUTHOR]

Objective The performances of fluorinated surfactants by introducing fluorinated segments into sutfactants were studied. Methods Maleic anhydride, dodecyl primary amine, hexamethylene diisocyanate (HDI), perfluorobutyl ethanol and sodium bisulfite were used to synthesize wetting and emulsifying fluorinated surfactants( EFS). The structure of EFS was characterized by FTIR and ' HNMR. The wettability, emulsifying and oil displacement properties of EFS were investigated. Results The EFS can effectively improve the wettability and change the oil-wet glass surface into neutral surface, showing wetting reversal properties. Besides, the emulsification and solubilization performance indicated that 0.2% EFS has good emulsifying properties for crude oil. Moreover, the EFS presented good oil displacement performance, and more than half of crude oil in capillary can be driven out when the concentration of EFS was 0. 2% within 24 hours. Meanwhile, the larger angle between capillary and bottle bottom, the easier the crude oil is driven out. [ABSTRACT FROM AUTHOR]

Copyright of Energy Chemical Industry is the property of Energy Chemical Industry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A series of novel nonionic hydrocarbon/fluorocarbon hybrid surfactants (Hm-Fn, where m = 10, 12, 14, 16 and n = 4, 6, respectively) were successfully synthesized using polyethylene glycol, isophorone diisocyanate (IPDI), short chain fluoroalkyl alcohol and alkyl alcohol as starting materials. The preparation process involves the coupling reaction of isocyanate and hydroxyl groups. The surface activity and aggregation behavior of Hm-Fn in aqueous solution were studied by surface tension, steady-state fluorescence and dynamic light scattering (DLS) and transmission electron microscopy (TEM). The influence of the hydrophobic (hydrocarbon or fluorocarbon) chain length on surface activity of such hydrocarbon/fluorocarbon hybrid surfactants was systematically investigated. Micromorphology analysis revealed the presence of different sizes vesicles in H16-F6 and H16-F4 aqueous solution. In addition, the hydrophobic dye solubilization experiments exhibited that H16-F6 with a relatively longer fluorocarbon chain and hydrocarbon chain possessed more outstanding solubilization of model dye (Sudan I) compared with other Hm-Fn and conventional hydrocarbon surfactants. The molar solubilization power of H16-F6 could reach 0.0537. The above results demonstrated that these nonionic hydrocarbon/fluorocarbon hybrid surfactants might possess potential application prospects for hydrophobic dyes solubilization. [ABSTRACT FROM AUTHOR]

Summary: Proton‐conducting gel electrolytes offer significant advantages for supercapacitors. Among various acids, phosphoric acid (H3PO4·H2O, PA) has the highest proton conductivity for use as a supercapacitor electrolyte. Compared with commonly used acidic and basic electrolytes (H2SO4 and KOH), a high specific capacitance of approximately 620 F g−1 was attained for PA under 0.1 A g−1 test conditions in combination with a reduced graphene oxide (rGO) symmetric electrode. Moreover, the PA electrolyte was further improved by confining it to a liquid crystal (LC) gel matrix. PA and a non‐ionic surfactant (lauryl ether, C12H25[OCH2CH2]10OH) were used to form LC gels with PA:NI mole ratios 60 to 100:1, which had viscosity values in 800 to 5500 mPa s−1 range at a shear rate of 100 s−1 and provided a high gravimetric specific capacitance of approximately 1128 F g−1 when tested at 0.1 A g−1 with an rGO symmetric electrode. The mesophase of the LC gel at each PA:NI mole ratio was comprehensively analyzed using X‐ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR), and polarized optical microscopy (POM) to confirm that the mesostructure was responsible for the high specific capacitance. The electrochemical performance was studied using electrochemical methods and galvonastatic charge/discharge tests. Furthermore, to increase the energy density of supercapacitors, focusing on automotive applications, this LC gel electrolyte could be used in an asymmetrical pseudocapacitor design. [ABSTRACT FROM AUTHOR]

Alpha-Synuclein is a presynaptic neuronal protein whose masses are involved in Parkinson's disease, a chronic and progressive neurodegenerative disorder of the central nervous system. It has been observed that upon exposure to anionic surfactants, fluorinated alcohols and membranes in vitro, α -synuclein adopts alpha helix structure and can be fibrillated, while in aqueous solution, the protein is intrinsically disordered and the fibrillation is undesirable. Solvent is one of the most critical environmental parameters in biological studies as well as computer simulations. In this paper, we have investigated the effect of solvent composition on the conformation of α -synuclein protein using molecular dynamics (MD) simulations. For this purpose, the effect of different combinations of water and trifluoroethanol (TFE) solvents on the secondary structure of a fragment of α -synuclein was investigated. Moreover, thermodynamic calculations were performed through a coarse-grained (CG) model of solutions with different concentrations of α -synuclein in the aqueous phase and in TFE medium. The potential of mean force (PMF) calculations was performed as a function of separation distance between the centers of masses of two peptides. The results indicated that in the presence of TFE, the secondary structures have a regular arrangement of amino acids stabilized by hydrogen bonding patterns. In addition, decreasing the TFE concentration reduces the stability of α -helix structures of the protein. It seems that in diluted TFE solutions, high concentrations of water in the medium lead to the breakage of peptide–TFE hydrogen bonds. However, the hydrophobic nature of TFE and α -synuclein molecules prevents further aggregation in the concentrated solutions. The α-synuclein can be fibrillated in the presence of Trifluoroethanol (TFE). Stability of α-helix structure of peptide reduces as TFE concentration decreases. Hydrophobic nature of TFE and α-synuclein molecules prevents further aggregation. [ABSTRACT FROM AUTHOR]

Organofluorine compounds have had an increasing impact in synthetic organic chemistry and pharmaceutical research over the past two decades. Their syntheses and the development of novel synthetic approaches towards versatile fluorinated small molecules have received great interest. Our research team has designed various selective and stereocontrolled methods for the construction of fluorine-containing small molecular entities, involving the transformation of various functionalized cycloalkenes across their ring olefin bond. The synthetic methodologies developed to access various pharmacologically interesting fluorinated derivatives with multiple chiral centers might be valuable protocols for the preparation of other classes of organic compounds as well. [ABSTRACT FROM AUTHOR]

Approaches to the development of submicron and nanocrystalline silicate materials of MFI structure in a fluorinated surfactant medium were studied with perfluorononanoic acid as an example. In fluorinated surfactants, the crystal structure of the zeolite framework is formed more slowly than in the case of silicalite-1 because of the presence of aluminum atoms. The fractions of the formed Brønsted and Lewis acid sites in zeolites are independent of the amount of aluminum introduced into the reaction mixture. In oligomerization of light alkenes, the activity and operation stability of the synthesized zeolite with lower concentration of Brønsted acid sites and smaller crystal size are similar to those of the commercially available catalyst. [ABSTRACT FROM AUTHOR]

The management of brain diseases remains a challenge, particularly because of the difficulty for drugs to cross the blood–brain barrier. Among strategies developed to improve drug delivery, nano-sized emulsions (i.e., nanoemulsions), employed as nanocarriers, have been described. Moreover, focused ultrasound-mediated blood–brain barrier disruption using microbubbles is an attractive method to overcome this barrier, showing promising results in clinical trials. Therefore, nanoemulsions combined with this technology represent a real opportunity to bypass the constraints imposed by the blood–brain barrier and improve the treatment of brain diseases. In this work, a stable freeze-dried emulsion of perfluorooctyl bromide nanodroplets stabilized with home-made fluorinated surfactants able to carry hydrophobic agents is developed. This formulation is biocompatible and droplets composing the emulsion are internalized in multiple cell lines. After intravenous administration in mice, droplets are eliminated from the bloodstream in 24 h (blood half-life (t1/2) = 3.11 h) and no long-term toxicity is expected since they are completely excreted from mice' bodies after 72 h. In addition, intracerebral accumulation of tagged droplets is safely and significantly increased after focused ultrasound-mediated blood–brain barrier disruption. Thus, the proposed nanoemulsion appears as a promising nanocarrier for a successful focused ultrasound-mediated brain delivery of hydrophobic agents. [ABSTRACT FROM AUTHOR]

[Display omitted] Can surface-active particles be designed à la carte just by incorporating functional groups mimicking the structure of the solvent and gas? This is based on the idea that, to achieve good foamability, the particle wettability needs to be finely tuned to adjust the liquid-particle and gas-particle surface tensions. In practice, could particles containing phenyl rings and alkyl chains assemble at the air–liquid interface and stabilize foams based on aromatic solvents? A library of organosilica particles was prepared by sol–gel synthesis using aromatic organosilane precursors. The particles were characterized by TGA, FTIR and 13C/29Si MAS NMR. The foaming properties were studied after hand shaking and high-speed homogenization. The influence of particle wettability and solvent properties on foam formation was systematically investigated. A comparison was carried out between biphenyl-bridged particles and various stabilizers on foamability in benzyl alcohol. Biphenyl-bridged particles could stabilize foams in aromatic solvents with a high foam volume fraction up to 96% using Ultra-Turrax. The presence of biphenyl rings and short alkyl chains was crucial for foamability. Organic foams were prepared for aromatic solvents with intermediate surface tension (35–44 mN m−1) and contact angle in the range 32–53°. Biphenyl-bridged particles outperformed polytetrafluoroethylene and fluorinated surfactants in benzyl alcohol. [ABSTRACT FROM AUTHOR]

Accumulation of liquids near the wellbore in gas reservoirs can result in what is known as liquid banking, causing loss of gas and liquid production. One of the techniques that can be used to mitigate liquid banking is changing the rock wettability from liquid wetting to neutral wetting, allowing the gas to carry the liquid out of the pore space. Double‐functionalized wettability altering silica (SiO2) nanoparticles (NPs) were developed. The synthesized NPs were functionalized with both fluoro‐silane (F‐SiO2 NPs) and a charged functional group to enable coupling of the NPs to the substrate. Surfaces treated with F‐SiO2 NPs functionalized with coupling functional group showed superior wear and corrosion resistance in high salinity water compared to single‐functionalized F‐SiO2 NPs. By functionalizing 125 nm SiO2 NPs first with polyethylenimine (PEI‐) or N‐(2‐Aminoethyl)‐3‐aminopropyltrimethoxysilane (DAMO‐) l group followed by fluorination, a water contact angle of 120°and decane contact angle of 70° was achieved. Core flow testing performed under realistic reservoir conditions of pressure and temperature showed that F‐SiO2 NPs coated with PEI achieved a 58% improvement in gas and liquid relative permeability, indicating improvement in the surface repellency to liquids and reduction of the trapped liquid phases inside the pore space of the rocks. The developed double‐functionalized NPs achieved similar performance to the commercially used fluorinated surfactants but using less treatment volume. In addition, these double‐functionalized NPs enable one‐step treatment in the field, which results in simpler operations, shorter treatment time, and better treatment economics. [ABSTRACT FROM AUTHOR]

Formamidinium lead triiodide‐based perovskite solar cells have emerged as one of the most promising candidates that can be potentially used to develop photovoltaic technologies in the future. The commercial use of perovskite solar cell modules (PSCMs) is limited as it is challenging to fabricate high‐quality, efficient, and stable large‐area perovskite light‐absorbing films. Heptadecafluorooctanesulfonic acid tetraethylammonium salt (HFSTT), containing fluorinated long alkyl chains as hydrophobic tails and sulfonic acid groups (SO3−) as hydrophilic heads, which exhibit a great synergistic potential in large‐area film uniform fabrication, crystallization orientation modulation, defect passivation, and device operation stability enhancement, are introduced. The HFSTT‐modified films exhibit a prominent (100) orientation and lower trap‐state density as well as enhanced carrier mobilities and diffusion lengths, facilitating a champion unit device with an impressive power conversion efficiency (PCE) of 23.88% (0.14 cm2) and 22.52% (1 cm2) with a low voltage deficit around 0.341 V. The unencapsulated device retains ≈70% of its initial efficiency after 1000 h under heat damping test (60 °C and ≈60% RH). Moreover, the PSCMs exhibiting PCEs of 21.05% (with notable fill factor 0.79) and 18.27% are characterized by the active areas of 25.98 and 60.68 cm2, respectively. [ABSTRACT FROM AUTHOR]

A new class of carboxylic acid-terminated gemini surfactants which contain the smallest possible headgroup linker (a single bond) has recently been reported in the literature. In this current work, we have explored how Langmuir monolayers of two different alkyl tail chain length variants (n = 12, n = 16) of these surfactants, dubbed C n -0-C n , are impacted by mixing with a benchmark perfluorinated surfactant, perfluorotetradecanoic acid (PF). Pure PF and C 16 -0-C 16 monolayers share similar general characteristics, yielding compact, incompressible, solid-like films at the air-water interface. In contrast, the shorter tail chain variant, C 12 -0-C 12 forms expanded, compressible liquid-like films. While both tail chain variants formed mixed films with PF that were generally expanded in comparison with their pure components, and were also phase-separated, the extent of interactions between film components and the resulting micron-scale morphology of the mixed films were different for the two alkyl chain lengths. Overall, PF induces different packing behavior in both the systems and the observations are attributed to the difference in the dispersion forces originating from the tail chain length differences. [Display omitted] [ABSTRACT FROM AUTHOR]

• Fluorinated surfactants have a good performance in reducing gas/brine surface tension. • Brine salinity has an important role in the performance of fluorinated surfactants to change wettability. • Adsorption trapping is an important storage mechanism in aquifers. • Changing the wettability of deep saline aquifers to gas-wetting can help to enhance gas storage capacity. Deep saline aquifers are considered one of the possible candidates for underground gas storage. Wettability alteration of reservoir rock from liquid-wetting to gas-wetting could increase gas storage capacity in these geological structures. To the best of our knowledge, it is reported minor information regarding the enhancement of gas storage capacity using fluorinated surface-active materials under high salinity conditions. In this study, we employed a non-ionic fluorinated surfactant to study the wettability alteration of carbonate cores to gas-wetting. Thus, we designed and performed a systematic experimental analysis, namely SEM, EDX, and EDX mapping experiments, contact angle measurements, spontaneous imbibition, and core flooding experiments. The results of the experiments showed a considerable surface tension and contact angle reduction due to the use of fluorinated suractants. For instance, the surface tension was decreased from 71 to 20 mN/m, and water contact angle increased by 35–50 degrees, which showed a decreased tendency of the rock surface to the water phase. Subsequently, spontaneous imbibition of water in N 2 -saturated carbonate core plugs was performed, both in surfactant-treated and untreated cores. In the treated N 2 -saturated core plug, a weaker and slower spontaneous water imbibition occurred, i.e., water imbibition decreased from 47% to 20%. This showed an increase in the capacity of the gas storage in the treated core plug. Also, core flood tests were carried out in both treated and untreated cores, and it revealed that the pressure drop of the water phase in the treated core plug was decreased by 1.2 compared to the untreated core plug. This can be attributed to the fact that due to the change in the rock wettability, a lower phase blockage in the core was happened. The results of this study were consistent with the literature results, and it can lead to an improved gas storage capacity in carbonate rocks. In summary, the results of this study can be considered helpful for different underground gas storage processes namely CO 2 sequestration, H 2 geo-storage, and natural gas storage in saline aquifers using fluorinated surfactants. [ABSTRACT FROM AUTHOR]

Chlorinated polyfluorinated ether sulfonate (Cl-PFESA), a substitute for perfluorooctane sulfonate (PFOS), has been widely used in the Chinese electroplating industry under the trade name F-53B. The production and use of F-53B is keep increasing in recent years, consequently causing more emissions into the environment. Thus, there is a growing concern about the adverse effects of F-53B on human health. However, related research is very limited, particularly in terms of its toxicity to the vascular system. In this study, C57BL/6 J mice were exposed to 0.04, 0.2, and 1 mg/kg F-53B for 12 weeks to assess its impact on the vascular system. We found that F-53B exposure caused aortic wall thickening, collagen deposition, and reduced elasticity in mice. In addition, F-53B exposure led to a loss of vascular endothelial integrity and a vascular inflammatory response. Intercellular cell adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) were found to be indispensable for this process. Furthermore, RNA sequencing analysis revealed that F-53B can decrease the repair capacity of endothelial cells by inhibiting their proliferation and migration. Collectively, our findings demonstrate that F-53B exposure induces vascular inflammation and loss of endothelial integrity as well as suppresses the repair capacity of endothelial cells, which ultimately results in vascular injury, highlighting the need for a more thorough risk assessment of F-53B to human health. [Display omitted] • F-53B exposure induced vascular injury in C57BL/6 J mice. • F-53B exposure induced vascular inflammation and loss of endothelial integrity. • F-53B exposure inhibited the repair capacity of HUVECs. [ABSTRACT FROM AUTHOR]

Aqueous film‐forming foams (AFFFs) are an important for fire extinguishing, and their key ingredient is fluorinated surfactant. In recent years, traditional long‐chain fluorinated surfactants have been banned by most countries because of their persistence, bio‐accumulation and toxicity. Therefore, increased attention has been paid to the research and development of short‐chain fluorinated surfactants. As is well known, the introduction of hydrophilic or hydrophobic groups in a surfactant affects its surface activity, and therefore, the fire extinguishing performance of AFFFs. In this work, a series of short‐chain fluorosurfactant‐based AFFFs with different hydrophobic chain lengths were prepared. The physicochemical performance of mixed systems (fluorinated surfactant plus sodium hexanesulfonate), including surface activity, spreading ability, foam expansion, drainage time, and the fire extinguishing and burn‐back performance of AFFFs were studied. The results show that the critical micelle concentration (CMC) and the surface tension (γCMC) at the CMC of mixed systems at 25°C are lower than 7.68 mmol/L and 16.51 mN/m, respectively. For mixed systems, the average spreading rate is more than 1.09 cm/s, the foam expansion is over 7.1, and the drainage time is greater than 3.28 min. The fire extinguishing time of AFFFs on fuels is less than 51 s while the burn‐back time is more than 15.18 min. The results imply a potential application prospect of the short‐chain fluorinated surfactants in AFFFs. [ABSTRACT FROM AUTHOR]

Per‐ and polyfluoroalkyl substances are a class of fluorochemicals that can degrade into perfluoroalkyl acids, which are well known to be persistent in the environment. It is thus important that novel fluorinated surfactants be designed to degrade into small, nonbioaccumulative products. We report the biotransformation and elimination kinetics of one such novel polyfluorinated surfactant, di(polyfluoroether thioether(S)‐oate) sulfonate (diFESOS), and its metabolites. Biotransformation was investigated in vitro using S9 liver fractions and in vivo in Sprague–Dawley rats. Rats dosed by oral gavage with diFESOS were found to have relatively fast elimination kinetics, with half‐lives on the order of hours, compared with legacy fluorinated surfactants such as the disubstituted polyfluoroalkyl phosphates that have half‐lives on the order of days. To interrogate degradation of the polyfluorinated chain, rats were then dosed with a polyfluoroether thioether alcohol (a suspected product of carboxylate cleavage of diFESOS) either orally or intravenously, and the novel metabolite 2H‐3:2 polyfluoroether sulfonic acid (2H‐3:2 PFESA) was identified. Perfluoropropionic acid was detected in rat urine and is likely a terminal product. The blood of orally dosed rats contained higher levels of metabolites than the blood of intravenously dosed rats, suggesting the importance of metabolism in the gut and liver. Elimination kinetics of all the novel metabolites were faster than their fully fluorinated counterparts. Environ Toxicol Chem 2021;40:3328–3336. © 2021 SETAC [ABSTRACT FROM AUTHOR]

Summary: Spreading coefficient, foam degradation, fuel transport through a foam layer, foam spread, and fire extinction time were collected by varying fuels for a given fluorosurfactant formulation. Varying fuel structure systematically enabled variation of foam‐fuel interactions, and spreading coefficients, which affected aqueous film formation. A wide range of spreading coefficients were studied using two foam formulations. Surfactant formulations with near‐zero or negative spreading coefficients (−1.2, −0.12 mN/m) suppressed the fires within the same time or faster than those with positive spreading coefficients (1.77, 3.28 mN/m). Both foams extinguished an iso‐octane and methylcyclohexane pool fire despite negative spreading coefficients on iso‐octane and positive spreading coefficients on methylcyclohexane. The fire extinction times collected relate more closely to foam degradation than to film formation. Foam degradation results showed a roughly 20% variation in lifetime between the two foams and the three fuels, consistent with fire extinction times. To understand the relationship between foam degradation and solution properties, a single lamella experiment was designed that monitors lamella thickness and lifetime. This experiment, relating solution to foam properties, will aid in the development of environmentally friendly surfactant replacements in firefighting foams. [ABSTRACT FROM AUTHOR]

Droplet microfluidics has recently emerged as a powerful platform for a variety of biomedical applications including microreactors, bioactive compound encapsulation, and single cell culture and analysis; all these applications require long-term droplet stability, which, however, makes breaking the emulsion and retrieving the loaded samples difficult. Herein, we developed a novel class of thermo-responsive fluorosurfactants to control the droplet status simply by temperature. The surfactants were synthesized by coupling perfluorinated polyethers (PFPEs) with a thermo-responsive block of poly(N-isopropylacrylamide) (pNIPAM) or poly(2-ethyl-2-oxazoline) (pEtOx) with lower critical solution temperature (LCST). These diblock surfactants can stabilize the emulsion at temperatures below LCST due to the hydrophilic head, which became hydrophobic upon increasing the ambient temperature above LCST, thereby destabilizing the droplets and realizing demulsification simply via temperature control. The diblock surfactant can be applied for templating cell encapsulation using alginate microgels, which allowed one-step and high-throughput microfluidic generation of cell-laden microgels without compromising cell viability. This non-invasive, on-demand demulsification strategy provides a high degree of freedom for microencapsulation and on-demand recovery of the samples or reaction products within the droplets, which opens a new avenue for a wide range of applications of droplet-templating microfluidics. [ABSTRACT FROM AUTHOR]

As an innovative approach, cadmium sulfide (CdS) nanorod was synthesized and applied to modify a fluorinated-tin oxide conducting glass (SnO2:F) as a matrix for urea bioelectrode. Besides, urease (Urs) was exploited as a particular enzyme for urea recognition with excellent accuracy and precision via a unique mechanism. In this case, Urs has immobilized physically over the matrix superficial (CdS/SnO2:F) electrode. Initially, the fabricated CdS nanorods qualities were deliberated by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD) analyses while the fabricated Urs/CdS/SnO2:F bioelectrode was considered employing electrochemical impedance spectroscopy (EIS) and cyclic voltammetric (CV) techniques. The modified bioelectrode efficiency for urea analysis was presented while the parameters affecting the peak current were improved. Under the best circumstances, the novel bioelectrode illustrated a linear response over an extensive range of urea concentrations (5 to 200 mg dL-1), the detection limit was 3 mg dL-1. The projected Urs/CdS/SnO2:F bioelectrode has a fast response time of less than 3 s. The technique was exploited to the urea measurement in pharmaceutical preparation and human serum samples, and suitable outcomes were acquired. [ABSTRACT FROM AUTHOR]

A partially fluorinated surfactant, CF-S, was prepared using p-trifluoromethyl aniline as the starting material. Its UV-Vis spectrum was measured. The photoisomerization of CF-S was studied. The surface tension of the CF-S solution was measured. The corresponding physicochemical parameters were calculated. The properties of CF-S were compared with those of CH-S, a surfactant without fluorine. It was found that the surface activity of CF-S was significantly stronger than that of CH-S. After UV light irradiation, CF-S showed higher cmc and γcmc, lower Γmax and greater ᴀmin. The wettability of CF-S to quartz was measured. The fluorinated surfactant can improve the hydrophobicity of the quartz surface. The contact angle of CF-S on the quartz surface was decreased by UV light irradiation. So the wettability of CF-S was increased. The Zeta potential of the quartz particles was measured in the CF-S solution. After adding CF-S into the solution, the Zeta potential of the quartz particles was increased. After UV irradiation, the Zeta potential of quartz was decreased. Some adsorbed surfactants were desorbed from the quartz surface. [ABSTRACT FROM AUTHOR]

Due to mounting evidence of the negative health effects of persistent perfluoroalkyl acids (PFAAs) with long (i.e., >C7) tails, there is a need for convenient systems capable of sensing these contaminants at dilute aqueous concentrations. To address this concern, a thermoresponsive polymeric network composed of poly(N-isopropylacrylamide) copolymerized with fluorinated comonomers was studied to characterize the gel's physical response to fluorosurfactants in solution. Incorporating fluorinated comonomers into the polymer backbone raised their swelling in fluorocontaminant solutions relative to water – gels synthesized with 10.0 mol% 2,2,2-trifluoroethyl acrylate (TFEA) displayed a heightened maximum water-analyte swelling difference of 3761 ± 147% compared to 3201 ± 466% for non-fluorinated gels in the presence of 1 mM tetraethylammonium perfluorooctane sulfonate (TPFOS). The normalized area under the curve for gels with 12.5 mol% TFEA was further raised to 1.77 ± 0.09, indicating a broadened response window for the contaminant, but at the cost of reducing the overall swelling ratio to 3227 ± 166% and elongating the time required to reach swelling equilibrium. Overall, a copolymer fed with 10.7 mol% TFEA was predicted to maximize both the swelling and response window of the polymer toward TPFOS. Equilibration times followed a logarithmic increase as the percentage of comonomer was raised, noting gradual fluorosurfactant penetration into the gels impeded by initial gel compaction caused by the addition of fluorinated comonomers. Comparative study of gels containing 1H,1H,7H-dodecafluoroheptyl acrylate, TFEA, or 1,1,1,3,3,3-hexafluoroisopropyl acrylate identified careful selection of fluorinated comonomers and their feed ratios as useful tools for tailoring the network's swelling response to TPFOS. [ABSTRACT FROM AUTHOR]

Copyright of Coatings & Protection / Tuceng yu Fanghu is the property of Coating & Protection Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Gemini surfactants have aroused significant attention since their discovery due to their unique properties that arise from the particular molecular structure. However, the effect of a C C double bond in the spacer has seldom been considered, and common quaternary ammonium-based gemini surfactants have seldom been compared with imidazolium-based ones. In this work, four gemini surfactants, denoted as 12–4-12, 12–4u-12, C12im-4-C12im, and C12im-4u-C12im were synthesized and characterized, and the effects of C C double bond in the spacer and hydrophilic headgroup on the fundamental properties were investigated. The results showed that imidazolium-based gemini surfactants (C12im-4-C12im and C12im-4u-C12im) have lower critical micelle concentration (cmc), greater efficiency and effectiveness in reducing surface tension, and superior ability to generate micelles compared to the corresponding quaternary ammonium-based ones, but showed comparatively lower salt resistance, foaming, and antibacterial activity. The introduction of C C in the spacer further decreased the cmc and the Gibbs free energy of micellization, and enhanced the antibacterial activity, but barely affected interfacial adsorption, the efficiency in reducing surface tension, micelle size, or foaming. None of the four gemini surfactants alone was capable of decreasing the interfacial tension to an ultra-low value. The incorporation of sodium cetanol polyoxyethylene ether carboxylate not only significantly decreased the interfacial tension (<10−2 mN·m−1), but also remarkably enhanced the salt resistance capacity up to 80,000 mg·L−1. This information may be helpful for designing new gemini surfactants tailored for different potential applications. [Display omitted] [ABSTRACT FROM AUTHOR]

AlH 3 has a high explosion risk due to rapid hydrogen evolution, and explosion suppression is necessary to reduce explosion hazard. Herein, we apply a common fire extinguishing agent, fluorinated surfactant, to suppress hydrogen in AlH 3. This stable composite suppressant has a structure resembling dry water, a dilute aqueous solution of FS-50 encapsulated by fumed phase SiO 2 , which not only improves suppression effect but also significantly reduces the damage of fluorine to the environment. Fluorinated intermediate radicals F, CF, CF 3 , CHF, CHF 2 , etc. produced by decomposition of FS-50 interrupt the chain reaction of flame radicals H, O, OH to produce (-CH 2 -CF 2 -) n and stable product HF. Additionally, the outflow of fluorinated compounds mixes with water and SiO 2 to form a cladding layer, which prevents heat propagating from the reaction zone to preheating zone. Our work will pave the way for the widespread and safe application of light metal hydrogen storage materials. [Display omitted] • DW modified with FS-50 has a significant suppression effect on AlH 3 explosion. • Fluorinated radicals interrupt the hydrogen radical chain reaction. • The cladding layer containing SiO 2 and F prevents heat propagation. [ABSTRACT FROM AUTHOR]

Due to negative effects of conventional fluorinated surfactants with long perfluorocarbon chain (CxF2x+ 1, x≥7) like perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), these conventional long perfluorocarbon chain surfactants have been restricted in many industrial applications. Nowadays, their potential non-bioaccumulable alternatives have been developed to meet the requirements of environmental sustainable development. In this paper, the recent advances of potential non-bioaccumulable fluorinated surfactants with different fluorocarbon chain structures, including the short perfluorocarbon chain, the branched fluorocarbon chain, and the fluorocarbon chain with weak points, are reviewed from the aspects of synthesis processes, properties, and structure-activity relationships. And their applications in emulsion polymerization of fluorinated olefins, handling membrane proteins, and leather manufacture also are summarized. Furthermore, the challenges embedded in the current non-bioaccumulable fluorinated surfactants are also highlighted and discussed with the hope to provide a valuable reference for the prosperous development of fluorinated surfactants. [ABSTRACT FROM AUTHOR]

Fluorinated surfactants, especially those with long fluorocarbon chains (CxF2x+1, x > 7) like perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), are used wildly in industrial and household fields. As research results have shown that such long fluorocarbon chain surfactants are seriously toxic, obviously persistent and highly bioaccumulative in the environment, it is an urgent requirement to develop novel alternatives of the long fluorocarbon chain surfactants. In this work, a series of novel nonionic fluorinated surfactants (FxCy-m) was synthesized by introducing an isophorone diisocyanate unit (as a spacer) between a short hydrophobic fluorocarbon chain (x ≤ 6) and a hydrophilic polyethylene glycol (PEG) chain with a facile two-step couple reaction using commercially available reagents. The chemical structures of FxCy-m were characterized by FT-IR and 1H NMR, and the relationships between length of hydrophilic/hydrophobic chains and surface activity of FxCy-m were systematically investigated by surface tension measurements. Among them, F6C2-400 with a longer fluorocarbon chain and a shorter PEG chain exhibits the highest surface activity, and its capability of reducing surface tension is almost equivalent to that of NaPFO (a derivative of PFOA). Meanwhile, F6C2-400 also has an excellent tolerance to salt and pH as well as an effective wettability. The facile preparation method and the clear structure-activity relationship in our research provide a valuable reference for development of nonionic surfactants with a short fluorocarbon chain. [ABSTRACT FROM AUTHOR]

The pressure drop during production in the near-wellbore zone of gas condensate reservoirs causes condensate formation in this area. Condensate blockage in this area causes an additional pressure drop that weakens the effective parameters of production, such as permeability. Reservoir rock wettability alteration to gas-wet through chemical treatment is one of the solutions to produce these condensates and eliminate condensate blockage in the area. In this study, an anionic fluorinated surfactant was synthesized and used for chemical treatment and carbonate rock wettability alteration. The synthesized surfactant was characterized by Fourier transform infrared spectroscopy and thermogravimetric analysis. Then, using surface tension tests, its critical micelle concentration (CMC) was determined. Contact angle experiments on chemically treated sections with surfactant solutions and spontaneous imbibition were performed to investigate the wettability alteration. Surfactant adsorption on porous media was calculated using flooding. Finally, the surfactant foamability was investigated using a Ross–Miles foam generator. According to the results, the synthesized surfactant has suitable thermal stability for use in gas condensate reservoirs. A CMC of 3500 ppm was obtained for the surfactant based on the surface tension experiments. Contact angle experiments show the ability of the surfactant to chemical treatment and wettability alteration of carbonate rocks to gas-wet so that at the constant concentration of CMC and at 373 K, the contact angles at treatment times of 30, 60, 120 and 240 min were obtained 87.94°, 93.50°, 99.79° and 106.03°, respectively. However, this ability varies at different surfactant concentrations and temperatures. The foamability test also shows the suitable stability of the foam generated by the surfactant, and a foam half-life time of 13 min was obtained for the surfactant at CMC. [ABSTRACT FROM AUTHOR]

The facile synthesis approach, surface-active properties, and anti-corrosive efficiency of innovative urea-based cationic fluorinated surfactants (FUS) of variable alkyl chain length were investigated. The effect of as-prepared FUS inhibitors on carbon steel corrosion in 15% HCl solution at 20–50 °C was examined using weight loss and various electrochemical methods (open circuit potential (OCP) vs. time, potentiodynamic polarization (PDA) and electrochemical impedance spectroscopy (EIS) methods). The corrosion protection capacities at an optimum concentration (0.5 mM) are 93.2% (FUS-8), 96.3% (FUS-10) and 97.6% (FUS-12) by PDA, comparable to the findings achieved by EIS. PDA measurements indicated that the studied FUS act as inhibitors of mixed-type and chemical adsorption on a carbon steel interface following the Langmuir isotherm model. The thermodynamic and kinetic indices of the corrosion and adsorption processes were estimated and interpreted. Surface examinations by X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FTIR), field emission scanning electron microscopy and energy dispersive X-ray analysis (FESEM/EDX) revealed the formation of a protecting layer at the carbon steel/HCl interface. Quantum chemical indices (DFT based) delivered more understanding of the inhibition mechanism. Molecular dynamics (MD) simulations were accomplished to explore the configurational adsorption performance of the studied fluorosurfactants on the iron(110) interface. It is supposed that these findings are of some significance for the reasonable design of effective inhibitors for acidic corrosion. [ABSTRACT FROM AUTHOR]