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We investigated if maternal body burdens of perfluoroalkyl acids (PFAAs) at the time of delivery are associated with birth outcome and if early life exposure (in utero/nursing) is associated with early childhood growth and weight gain. Maternal PFAA body burdens were estimated by analysis of serum samples from mothers living in Uppsala County, Sweden (POPUP), sampled three weeks after delivery between 1996 and 2011. Data on child length and weight were collected from medical records and converted into standard deviation scores (SDS). Multiple linear regression models with appropriate covariates were used to analyze associations between maternal PFAA levels and birth outcomes (n = 381). After birth Generalized Least Squares models were used to analyze associations between maternal PFAA and child growth (n = 200). Inverse associations were found between maternal levels of perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), and perfluoroundecanoic acid (PFUnDA), and birth weight SDS with a change of − 0.10 to − 0.18 weight SDS for an inter-quartile range (IQR) increase in ng/g PFAA. After birth, weight and length SDS were not significantly associated with maternal PFAA. However, BMI SDS was significantly associated with PFOA, PFNA, and PFHxS at 3 and 4 years of age, and with PFOS at 4 and 5 years of age. If causal, these associations suggest that PFAA affects fetal and childhood body development in different directions. [ABSTRACT FROM AUTHOR]

The approaches for regiocontrolled N -, O - and C -methylation of 1-phenyl-3-polyfluoroalkyl-1 H -pyrazol-5-ols have been developed. The chemoselective N -methylation proved to be an efficient method for the synthesis of polyfluorinated antipyrine analogs. In addition, we reinvestigated the structure of 3-polyfluoroalkyl-1-phenylpyrazol-5-ols by the X-Ray analysis. The quantum-chemical calculations were used for an explanation of methylation processes. The preliminary biological testing revealed a significant analgesic activity of trifluoromethyl-containing antipyrine. [ABSTRACT FROM AUTHOR]

Most research efforts focus on synthesis of new biocides. This study shows that orientating biocidal groups on top surface with the help of a low-surface-tension constituent also imparts enhanced antibacterial ability. A CO2-philic biocidal silicone with pyridinium pendants was synthesized by hydrosilylation reaction of (45% methylhydrosiloxane)–dimethylsiloxane random copolymer (P(MHS–DMS)) and 4-vinylpyridine and subsequent quaternization of pyridine groups with 6-perfluorooctyl-1-bromohexane. The fluorinated pyridinium silicone was impregnated into cotton yarns in supercritical CO2 to form a 50 nm thickness biocidal layer at 24 MPa and 50 °C. Pyridinium groups preferentially segregated to the top surface with the aid of low-surface-tension perfluorooctyl segments and provided higher biocidal efficacy against Staphylococcus aureus and Escherichia coli compared to their counterparts that were quaternized with 1-bromohexane at similar total pyridinium content of about 4.65 × 1016/cm2. The synthesis and coating results were characterized by FTIR, SEM, and XPS. The stabilities of fluorinated pyridinium silicone layer toward washing cycles, UV irradiation, and storage were good. The presented strategy uses environmentally benign CO2 as solvent and affords a general method to functionalize polymers for improved biocidal capability due to the surface orientation of pyridinium groups. [ABSTRACT FROM AUTHOR]

The rheological properties of surfactant solutions play an important role in their applications. Here we study systematically how different cosurfactants affect the rheological properties of mixed solutions of the anionic surfactant sodium laurylether sulfate (SLES) and the zwitterionic cocoamidopropyl betaine (CAPB). Mixed SLES + CAPB solutions are used in various formulations due to their excellent foaming and cleaning properties. These solutions possess nearly Newtonian behavior and low viscosity. However, the addition of cosurfactants in low concentrations may significantly increase the viscosity of these solutions and even transform them into viscoelastic gels. Here we study systematically a wide range of ionic and nonionic cosurfactants with different head-groups, chain-lengths and structures of the hydrophobic tails (linear, branched, double bonded). We reveal an optimal chain-length of 8–10 carbon atoms of the cosurfactant molecules which ensures the highest viscoelasticity of the triple SLES + CAPB + cosurfactant solutions. Cationic cosurfactants and nonionic ones with small head-group (e.g. fatty alcohols and fatty acids) are most efficient in increasing the solution viscoelasticity. There is a hierarchy in the parameters of the cosurfactant molecules which govern this behavior − most important is the head-group charge, then the chain-length and, finally, the presence of branching and double bonds in the hydrophobic tails. The observed trends are explained with the effect of the cosurfactant molecules on the properties of the entangled wormlike micelles formed in these solutions. [ABSTRACT FROM AUTHOR]

Herein, with the aim of shedding light on the effect of non-ionic co-solute (carbohydrate) stereochemistry on the aggregation and surface behaviour of ionic liquid-based surfactant 1-decyl-3-methylimidazolium bromide ([C 10 mim][Br]) in aqueous solution, we studied the surface tension, electrical conductivity, volumetric and compressibility properties for the aqueous solutions of [C 10 mim][Br] in the presence of different sugars containing pentose monosaccharides (xylose, ribose and arabinose), hexose monosaccharides (glucose, and mannose), disaccharides (sucrose and lactose) and trisaccharide (raffinose) at different temperatures. From the electrical conductivity measurements, the values of the degree of ionization of the counter ion on the micelles (α) and thermodynamic properties of micellization (Δ G m ) for [C 10 mim][Br] in aqueous carbohydrate solutions were obtained. The various parameters such as apparent molar volume ( V ϕ ), isentropic compressibility (κ s ), apparent molar isentropic compressibility ( K ϕ ) and the change of apparent molar properties upon micellization (Δ V ϕ,m and Δ K ϕ,m ) were derived from the experimental density and speed of sound data. The surface tension measurements provided a series of parameters, including surface tension at the cmc ( γ cmc ), effectiveness of surface tension reduction ( Π cmc ), maximum surface excess concentration ( Γ max ) and minimum surface area per molecule ( A min ) at interface of air/solution for the investigated surfactant in the presence of different sugars at 298.15 K. All the investigated carbohydrates have soluting-out effect (favouring the micelle formation) and their abilities to reduce the cmc of [C 10 mim][Br] in aqueous solutions increase with an increase in the hydrophilicity of the carbohydrate. [ABSTRACT FROM AUTHOR]

The wide application of nanoparticles will lead its release into the aquatic environment, which may alter the bioavailability and toxicity of other contaminants to aquatic organisms. This work aimed to study the effects of perfluorooctane sulfonate (PFOS), single-wall carbon nanotubes (SWCNT), and their mixture on PFOS accumulation, antioxidant defenses and acetylcholinesterase (AChE) activity in zebrafish. The fish was dissected after being exposed (24, 48, 72 and 96 h) separately to PFOS, SWCNT and PFOS + SWCNT co-exposure. The bioaccumulation of PFOS in fish tissues (liver, intestines, gills and brain) decreased with increasing dosage of SWCNT, however, the opposite trend was observed in fish skin, which indicated that the bioavailability of PFOS changed by adsorption on SWCNT. Meanwhile, co-exposure induced more reactive oxygen species (ROS) than PFOS alone and enhanced the effect of PFOS on the superoxide dismutase (SOD), and catalase (CAT) and AChE activities. Furthermore, the integrated biomarker response (IBR) showed that co-exposure was the most stressful circumstance. [ABSTRACT FROM AUTHOR]

As one of the most reactive species, hydrated electron (e aq − ) is promising for reductive decomposition of recalcitrant organic pollutants, such as perfluorooctane sulfonate (PFOS). In this study, PFOS decomposition using a vacuum ultraviolet (VUV)/sulfite system was systematically investigated in comparison with sole VUV and ultraviolet (UV)/sulfite systems. A fast and nearly complete (97.3%) PFOS decomposition was observed within 4 h from its initial concentration of 37.2 μM in the VUV/sulfite system. The observed rate constant ( k obs ) for PFOS decomposition in the studied system was 0.87 ± 0.0060 h − 1 , which was nearly 7.5 and 2 folds faster than that in sole VUV and UV/sulfite systems, respectively. Compared to previously studied UV/sulfite system, VUV/sulfite system enhanced PFOS decomposition in both weak acidic and alkaline pH conditions. In weak acidic condition (pH 6.0), PFOS predominantly decomposed via direct VUV photolysis, whereas in alkaline condition (pH > 9.0), PFOS decomposition was mainly induced by e aq − generated from both sulfite and VUV photolytic reactions. At a fixed initial solution pH (pH 10.0), PFOS decomposition kinetics showed a positive linear dependence with sulfite dosage. The co-presence of humic acid (HA) and NO 3 − obviously suppressed PFOS decomposition, whereas HCO 3 – showed marginal inhibition. A few amount of short chain perfluorocarboxylic acids (PFCAs) were detected in PFOS decomposition process, and a high defluorination efficiency (75.4%) was achieved. These results suggested most fluorine atoms in PFOS molecule ultimately mineralized into fluoride ions, and the mechanisms for PFOS decomposition in the VUV/sulfite system were proposed. [ABSTRACT FROM AUTHOR]

Hazardous perfluoroalkyl acids (PFAAs), particularly perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA), have become ubiquitous environmental persistent organic contaminants, posing serious threats to environmental health, which has led to the development of PFAA treatment methods. Wetland construction in combination with iron-carbon (CW–I), a low-maintenance and high-efficiency technology, may be capable of removing PFAAs through physico-biochemical processes. In this study, we aim to investigate the removal efficiency of PFAAs by CW-I as well as the critical functions of all components within the wetlands. Pairwise comparisons of iron-carbon and control groups revealed that iron-carbon significantly enhanced 15.9% for PFOA and 17.9% for PFOS absorption through phytouptake and substrate adsorption, with respective removal efficiencies of 71.8% ± 1.03% and 85.8% ± 1.56%. The generated iron ions stimulated plant growth and further enhanced phytouptake of PFAAs, with PFAAs accumulated primarily in root tissues with limited translocation. Observations of batch adsorption suggest that chemical and electrostatic interactions are involved in the iron-carbon adsorption process, with film and intraparticle diffusions being the rate-limiting events. Fourier transform infrared spectrometer and X-ray photoelectron spectroscopy revealed that PFAA adsorption by substrates occurs at the molecular level, as well as the occurrence of hydrophobic force effects and ligand exchanges during the iron-carbon adsorption process. Additionally, iron-carbon significantly altered the genera, phyla, and community structure of microorganisms, and some microorganisms and their extracellular polymers may possess ability to bind PFAAs. The information provided in this study contributes to our understanding of the PFAA removal processes in CW-I and enriched the classical cases of PFAA removal by CWs. [Display omitted] • Iron-carbon boosted the PFAA removal efficiency in constructed wetland. • Phytouptake and substrate sorption are the primary pathways of removal. • Iron ions promoted plant growth and increased PFAA accumulation. • Sorption of PFAAs onto iron-carbon involved multiple interactions. [ABSTRACT FROM AUTHOR]

The disodium salt of 1-sulfo-cyclohexanecarboxylic acid (SCCA) was characterized by 1 H and 13 C NMR. The effects of SCCA on the surface activity of two high-Krafft-point fluorinated surfactants (potassium and sodium salts of perfluorooctanesulfonic acid, KPFOS and NaPFOS) and a conventional hydrogenated surfactant (sodium dodecylbenzene sulfonate, SDBS) were studied at room temperature. When SCCA was added, the effectiveness of KPFOS and NaPFOS in surface tension reduction was both greatly enhanced and KPFOS showed higher efficiency in surface tension reduction than NaPFOS. In particular, with the assistance of SCCA the minimum surface tension of fluorinated surfactants could even be as low as ∼18 mN/m at 25 °C. In contrast, the surface activity of SDBS was significantly reduced by SCCA, with the critical micelle concentation (cmc) largely increased. As a conclusion, the SCCA could act as an effective hydrotropic agent and it was able to recover the inherent character of KPFOS and NaPFOS as highly surface-active fluorinated surfactants by increasing their solubility. While for SDBS which was already soluble at room temperature, SCCA lowered the surface activity of SDBS. In addition, a preliminary study of application showed that SCCA was a qualified hydrotropic agent in formulations for industrial detergent and enhanced oil recovery. [ABSTRACT FROM AUTHOR]

The sorption of perfluoroalkyl substances on the sediments is an important process which determines to their fate, distribution and transport in water system. In this study, the sorption kinetics, thermodynamics and effect parameters on partition behavior of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) at low initial concentration (50 ng/L) were investigated. The results showed that the equilibrium was achieved within 48 h. The sorption isotherms of PFOS and PFOA could be described by Freundlich equation. The surface area and composition of sediment particles as well as solution pH values and ion strength strongly influenced the sorption of PFOA and PFOS. Both PFOA and PFOS exhibited higher sorption capacity on the sediments with high organic matter content. These results indicated that multiple driving forces such as hydrophobic exclusion, specific chemical interaction and electrostatic attraction contributed to the nonlinear sorption of PFOA and PFOS on sediments. [ABSTRACT FROM AUTHOR]

The synthetic protocols for symmetrical/unsymmetrical 3,6-disubstituted 1,1,2,2-tetrafluorocyclohexane molecules were successfully established for the first time. Some of thus obtained tetrafluorinated cyclohexanes underwent recrystallization to afford trans -configured products preferentially. One of the unsymmetrical trans -disubstituted tetrafluorocyclohexanes, trans -1-ethyl-2,2,3,3-tetrafluoro-4-[4-( trans -4- n -propylcyclohex-1-yl)phenyl]cyclohexane, was found to possess a low birefringence Δ n (0.073) and a large negative dielectric anisotropy Δ ε (–9.4) in a binary mixture system, which were very prominent as characteristics of LC molecules in VA-mode driving LC displays. [ABSTRACT FROM AUTHOR]

New olefin metathesis catalysts bearing unsymmetrical fluorinated NHC ligands with hexafluoroisopropylmethoxy group in ortho -positions of N -aryl-substituent have been synthesized. The effects of mono- ortho -arylsubstitution and the replacement of para -methyl N -aryl group with more electron-donating methoxy group in unsymmetrical fluorinated NHC ligand on the activity of complexes have been evaluated. [ABSTRACT FROM AUTHOR]

Expedient alkylations of 1-methyl-3H-imidazole-2-thione, a pharmaceutical active ingredient available in bulk quantities, provide high yield access to numerous protonated, or quaternized imidazoliums with chemospecific attachment of the fluoroponytail at the 2-mercapto functionality. The deprotonated primary target products represent valuable nitrogen heterocyclic bases, capable of further substitution, and salt or complex formation. Specific physicochemical characteristics that are relevant for phase and surface responsive behavior, e.g. critical micelle concentration, oleophobicity, depression of the aqueous surface tension, foam formation, emulsification of microgranular PTFE, are investigated for selected representatives and compared to the properties of common fluorosurfactants and ionic liquids. Remarkably, it is found that halogen bonding between iodide counterions of respective polyfluoroalkylmethimazolium systems and 1-iodoperfluoroalkanes, serving as the σ-hole partner of the halides, greatly affect the solubility profile of the resulting molecular adducts. Single-crystal X-ray structure determinations are carried out across the new fluorous substance classes. Strikingly, the helical arrangement of fluorine atoms along the chains typically encountered in polyfluorinated compounds is not found as the prevailing conformation. Rather, they are outnumbered by structural motifs exhibiting the rare zig-zag (linear alkane-like) chain conformation. Key derivatives are also subjected to preliminary ecotoxicological testing. [ABSTRACT FROM AUTHOR]

A novel magnetic fluorinated adsorbent with selective and fast adsorption of perfluorooctanesulfonate (PFOS) was synthesized via a simple ball milling of Fe3O4 and vermiculite loaded with a cationic fluorinated surfactant. The loaded Fe3O4 nanoparticles increased the dispersibility of fluorinated vermiculite (F-VT) in water and allowed the magnetic separability. The nanosized Fe3O4 was homogeneously embedded into the adsorbent surfaces, improving the hydrophilicity of F-VT external surface, and this hybrid adsorbent still kept the hydrophobic fluorinated interlayer structure. With this unique property, Fe3O4-loaded F-VT has very fast and selective adsorption for PFOS in the presence of other compounds, due to the fluorophilicity of C-F chains intercalated in the adsorbent interlayers. This novel adsorbent has a high sorption capacity for PFOS, exhibiting PFOS removal from fire-fighting foam wastewater that is much higher than that of powdered activated carbon and resin due to its high selectivity for PFOS. The used Fe3O4-loaded F-VT was successfully regenerated by methanol and reused five times without reduction in PFOS removal and magnetic performance. The Fe3O4-loaded F-VT demonstrates promising application for PFOS removal from real wastewater. [ABSTRACT FROM AUTHOR]

High internal phase emulsion (HIPE) technique has been of great interest for fabrication of polymer foams with controlled porous structures. However, for fluoropolymers, it has been a challenge to fabricate high-performance foams with controllable porous structures by HIPE due to the lack of suitable surfactant. Here, for the first time, a new type of cationic fluorosurfactant (CFS) is proposed to address this issue. The cationic fluorosurfactant is a diblock copolymer, Poly(2-dimethylamino)ethyl methacrylate- b -Poly(hexafluorobutyl acrylate) (PDMAEMA- b -PHFBA) synthesized by reversible addition − fragmentation chain transfer (RAFT) polymerization. For the prepared fluoro-diblock copolymer having similar fluorosegments to fluoro-monomer, this cationic fluorosurfactant can effectively stabilize high internal phase emulsion (HIPE) system involving hexafluorobutyl acrylate monomer as oil phase, water as internal phase, DVB as cross linker and AIBN as an initiator. Polymerization of the HIPE system finally gave rise to novel flexible fluoropolymer foam, Poly(HFBA-DVB) with a porous morphology which can be tuned simply by the amount of the fluorosurfactant. As a high-performance porous material, the fluoropolymer foam demonstrated not only significant capacities and fast adsorption kinetic for separating various organic oils from water, but also has an excellent thermal stability up to 340 °C, indicating significant applications at extreme conditions. [ABSTRACT FROM AUTHOR]

The brain level of perfluorododecanoic acid (PFDoA) was compared with those of perfluorooctanoic acid (PFOA) and perfluorodecanoic acid (PFDA) in rats 9 days after a single oral dose (50 mg/kg). The PFDoA level in the brain was 44.0 ± 2.0 µg/g, which was higher than that in the serum (24.4 ± 1.0 µg/ml). In contrast, the concentrations of PFOA and PFDA in the brain were low (<0.8 and 4.7 ± 0.4 µg/g, respectively), and less than one-tenth of those in the serum. Next, to investigate the effects on brain function, the cognitive function alterations of PFOA, PFDA, and PFDoA were estimated by the novel object recognition test 5-6 days after dosing. A significant decrease in the discrimination index was observed in PFDoA-treated rats while no significant alteration was observed in PFDA- and PFOA-treated rats. The effects of PFDoA were further assessed by other behavioral tests. PFDoA-associated alteration was observed in the elevated-plus maze test, but not in the Y-maze test, open-field test, and forced swim test. A decrease in the discrimination index of the novel object recognition test was dependent on the PFDoA dose and the PFDoA concentration in the brain. PFDoA concentration in the brain was 28.6 ± 2.6 µg/g 30 days after dosing, and a decrease in discrimination index was observed. Taken together, these results suggest that PFDoA distributes in the brain easier than PFOA and PFDA and causes cognitive deficit. [ABSTRACT FROM AUTHOR]

The effect of gas-wetting on the liquid-blocking effect near a wellbore region is significant. Here, we functionally modified nano-silica particles with a size of approximately 40 nm each by using a fluorosurfactant and obtained a super gas-wetting nano-silica particles, which could improve the contact angles of brine and hexadecane from 23° and 0° to 152° and 140°, respectively, and decrease the surface free energy of rock surface from 72 to 1.6 mN/m. The decrease in the gas displacement was approximately 30%. FT-IR, SEM and EDS were employed to determine the morphological change in the rock surface before and after gas-wetting alteration. Results indicate that when the fluorosurfactant molecules are joined to the nano-silica surface, and C F bond is recognized. The grape-like particles forming a multi-adsorption on the rock surface, which play an important role in super gas-wetting by decreasing surface free energy and increasing roughness on the rock surface. The data of EDS was consistent with the results of FT-IR and SEM. To further understand the influence of gas-wetting alteration on the flow and distribution of fluids in porous media, visualization flooding was conducted. The results show that the initial liquid saturation in the micromodel decreased sharply from 33.23% to 20.77% after the gas-wetting treatment, and the contact angle of isolated brine droplet on the treated pore-wall was approximately 125°, which also verifies that pore wettability can be altered to gas-wetting. The analytical data of the oil displacement experiment demonstrates that the substantial decrease in oil saturation may contributes to enhancing oil recovery. Furthermore, the mobility of oil trapped in micro channels can also be enhanced significantly after gas-wetting alteration due to the presence of methane. [ABSTRACT FROM AUTHOR]

Perfluorooctane sulfonate (PFOS) is a stable fluorosurfactant, which causes adverse effects in various organisms. The present study was designed to investigate the effects of Pyropia yezoensis peptide (PYP), a peptide comprised of 11 residues (ALEGGKSSGGG), on PFOS-induced endoplasmic reticulum (ER) stress in Chang cells. PFOS exposure (400 µM) for 24 h significantly decreased cell viability, which was upregulated by 250-1,000 pg/ml PYP treatment. Exposure to PFOS also significantly increased expression of the ER stress response protein, glucose-regulated protein 78 (GRP78), and phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2). These elevations were significantly decreased by PYP (250 pg/ml), and, in particular, the PFOS-induced GRP78 upregulation was decreased following treatment with 10 µM SL327, an ERK-kinase inhibitor. However, PYP-induced decreases in GRP78 expression and ERK1/2 phosphorylation were upregulated following treatment with LY294002 (20 µM), a phosphatidylinositol-3 kinase (PI3K) inhibitor. PFOS-induced apoptosis was also significantly attenuated by PYP (250 pg/ml) treatment, and the PYP-induced reduction in apoptosis was abolished by inhibition of PI3K. These findings indicate that negative regulation of ERK1/2 by PI3K is essential for the protective effects of PYP against PFOS-induced cell death, suggesting that PYP may be a candidate for therapeutic use. [ABSTRACT FROM AUTHOR]

This research focuses on performances of fluorinated surfactants-based coatings, which deposited on HSS-Co-E by sol-gel dip coating treatment. Fluorinated surfactants used in coating treatment consist of perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkyl phosphonic acids (PFPAs). Compositions of coatings were identified by Fourier Transform Infrared spectroscopy (FTIR), and surface morphologies were investigated by atomic force microscopy (AFM). Pin-on-disc frictional tests were carried out at room temperature and 300 °C, using uncoated and coated HSS-Co-E as pins and Ti–6Al–4 V as discs. Finish milling tests were carried to evaluate the performance of uncoated and coated tools by measuring cutting force, cutting temperature. Tool wear mechanisms were analyzed using scanning electron microscopy (SEM). Results showed that (1) Coated pins showed a much lower coefficient of friction (COF), and contact surfaces of coated pins were smoother with less titanium adhesive on it after tests. (2) Abrasive wear, adhesive wear and micro chipping were the main wear mechanisms of these two kinds of tools. Fluorinated surfactants acted as solid lubricants and protected the substrate, which obviously decreased adhesion and oxidation. The tool life of coated tool extended 50% compared with the uncoated one. (3) Surface integrity was analyzed by surface roughness and morphology. Surface roughness of plain surface machined by coated tools was much smaller than uncoated ones. In all, fluorinated surfactants-based coatings have the ability of reducing friction, anti-wear and smoothing surfaces due to their high chemical stability, high thermal stability and directional absorption on the substrate. [ABSTRACT FROM AUTHOR]

Using cyclic voltammetry (CV) and impedance (IMP), we report a simple approach to detect new fluorosurfactant ingredient formulated in aqueous film-forming foam (AFFF), specifically the thioether-based one. First, we employ ion chromatography (IC) to identify all possible elements with the help of chemical oxidation and infrared spectrum (IR) to identify all possible functional groups. We thus propose a possible thioether-based molecular structure of fluorosurfactant formulated in AFFF. By studying the self-assembled monolayer (SAM) formed on gold (Au) surface via thio-Au bond, we establish a relationship between the SAM density and the amount of the thioether-based fluorosurfactant for the AFFF detection. Solid phase extraction (SPE) and nanoporous Au electrode are employed to enhance the sensitivity. Consequently, a detection limit of 10 ppb (v/v) has been achieved for AFFF-spiked tap water sample. [ABSTRACT FROM AUTHOR]

Soil contamination is still poorly understood and modeled in part because of the difficulties of looking inside the "black box. constituted by soils. Here, we investigated the application of a recently developed 1H NMR technique to 19F NMR relaxometry experiments and utilized the results as inputs for an existing model. This novel approach yields 19F T2 NMR relaxation values of any fluorinated contaminant, which are among the most dangerous contaminants, allowing us to noninvasively and directly monitor their fate in soils. Using this protocol, we quantified the amount of a fluorinated xenobiotic (heptafluorobutyric acid, HFBA) in three different environments in soil aggregate packings and monitored contaminant exchange dynamics between these compartments. A model computing HFBA partition dynamics between different soil compartments showed that these three environments corresponded to HFBA in solution (i) between and (ii) inside the soil aggregates and (iii) to HFBA adsorbed to (or strongly interacting with) the soil constituents. In addition to providing a straightforward way of determining the sorption kinetics of any fluorinated contaminant, this work also highlights the strengths of a combined experimental-modeling approach to unambiguously understand experimental data and more generally to study contaminant fate in soils. [ABSTRACT FROM AUTHOR]

Cryopreservation is an important technique employed for the storage and preservation of biological tissues and cells. The limited effectiveness and significant toxicity of conventionally-used cryoprotectants, such as DMSO, have prompted efforts toward the rational design of less toxic alternatives, including carbohydrate-based surfactants. In this paper, we report the modular synthesis and ice recrystallization inhibition (IRI) activity of a library of variably substituted, carbohydrate-based fluorosurfactants. Carbohydrate-based fluorosurfactants possessed a variable mono- or disaccharide head group appended to a hydrophobic fluoroalkyl-substituted azobenzene tail group. Light-addressable fluorosurfactants displayed weak-to-moderate IRI activity that could be tuned through selection of carbohydrate head group, position of the trifluoroalkyl group on the azobenzene ring, and isomeric state of the azobenzene tail fragment. [ABSTRACT FROM AUTHOR]

In contrast to hydrogenated based systems that led to many studies, fluorinated surfactants have been little reported. Thanks to their high chemical and thermal stability, these compounds are considered as suitable candidates for the synthesis of porous materials with an enhanced hydrothermal stability. This study reports the synthesis of a new fluorinated surfactant, 2-trifluoromethyl-7,7,8,8,9,9,10,10,11,11,12,12,12-tridecafluoro-4-thia-1-dodecanoic acid (FSC) obtained from the thiol-ene radical addition of 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluoro-1-octanethiol onto 2-trifluoromethyl acrylic acid in 85% yield. In the aim of achieving micelles in water to design mesoporous materials according to the cooperative templating mechanism, FSC was modified with water-soluble telechelic diamine (Jeffamine) ED-600. The modified surfactant was deeply characterized by spectroscopic methods and the FSC-Jeffamine ED-600 micellar system was used as porogen to prepare mesoporous materials via the cooperative templating mechanism. Spherical wormhole-like mesostructured silica materials of high specific surface area (850 m 2 /g) and homogeneous pore size distribution (ca . 3.4 nm) were obtained by conveniently adjusting the porogen/silica molar ratio and the hydrothermal conditions. [ABSTRACT FROM AUTHOR]

Aqueous drops of a well-defined size are often used as small containers for conducting chemical and biochemical reactions, cell assays and as templates to produce microparticles. To prevent their coalescence, they must be stabilized, for example, using surfactants. The ability of different nonionic diblock and triblock copolymer surfactants to stabilize water drops that are dispersed in fluorinated oils is compared. In particular, the influence of the length of their hydrophilic poly(ethylene glycol) (PEG) block on the drop stability is studied. The stability of drops coated with triblock copolymers scales with the interfacial tension, whereas that of drops coated with diblock copolymers scales with their packing density. Surfactants whose ratio of the radii of gyration of PEG to the hydrophobic block (FSH) is between 0.54 and 0.67 impart the best stability to aqueous drops containing low salt concentrations. By contrast, surfactants whose ratio of the radii of gyration is between 0.34 and 0.37 impart the best stability to aqueous drops containing high salt concentrations. Hence, the choice of the best surfactant strongly depends on the composition of the fluids. [ABSTRACT FROM AUTHOR]

The aim of this article is to study the interactions between flavonoids and surfactants with attention of finding the probable location of flavonoids in micellar media that can be used for controlling their antioxidant behavior. In present study, the micellar and interfacial behavior of twin tailed anionic surfactants viz. sodium bis(2-ethylhexyl)sulfosuccinate (AOT) and sodium bis(2-ethylhexyl)phosphate (NaDEHP) in the presence of two flavonoids, namely quercetin (QUE) and kaempferol (KFL) have been studied by surface tension measurements. UV–visible, fluorescence and differential pulse voltammetric (DPV) measurements have been employed to predict the probable location of flavonoids (QUE/KFL) within surfactant (AOT/NaDEHP) aggregates. Dynamic light scattering (DLS) measurements further confirmed the solubilization of QUE/KFL in AOT/NaDEHP aggregates deduced from increased hydrodynamic diameter (D h ) of aggregates in the presence of flavonoids. Both radical scavenging activity (RSA) and degradation rate constant (k) of flavonoids are found to be higher in NaDEHP micelles as compared to AOT micelles. [ABSTRACT FROM AUTHOR]

Nano-sensors have received intensive attention due to their unique sensitivity and selectivity, which mainly originate from modifications and reactions that occur at nano scales. An important ingredient for these sensors is gold nanoparticle which has been developed as the core material to detect anions, in particular in contaminated water. Especially these nano-sensors find specific applications for selected harmful anions which include a controlled anion F − , toxic contaminants CN − and AsO 3 3 − / AsO 4 3 − , and anionic fluorosurfactants. The anionic fluorosurfactants mainly include perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), both of which have recently been listed as emerging contaminants and categorised as persistent organic pollutants. This review addresses recent advancements in the development of gold nanoparticle-based nano-sensors for such anions and outlines their performance limitations towards on-site applications. [ABSTRACT FROM AUTHOR]

Aqueous foams are ubiquitous in nature and have important applications in enhanced oil recovery, food industry, pharmaceuticals, and firefighting. Foams are intrinsically metastable and degrade quickly to form water when exposed to hydrocarbons. Contrary to the hydrocarbon-induced foam degradation, we describe spontaneous foam generation from a thin layer of immiscible, volatile, hydrocarbon liquid floating on an aqueous fluorosurfactant solution at quiescent, ambient, conditions in a 17-cm diameter vessel. Foaming occurs at under-saturation and is different from the spontaneous foam generation from boiling liquids or cavitation or effervescence of dissolved gases at over-saturated conditions. By varying parameters, we reveal the underlying processes and conditions and quantify their effects on foam volume. We also quantify the unique ability of fluorosurfactants to spontaneously form foams unlike fluorine-free surfactants. This is because the hydrocarbon evaporation drives foam generation and foam-degradation simultaneously, and the degradation dominates for fluorine-free surfactants. To understand the mechanisms of foaming, experiments with a single hydrocarbon droplet floating on the aqueous solution are performed. They show that the vapor formed by the evaporating drop diffuses directly into ambient air below its boiling point but some of it nucleates bubbles at the surfactant laden drop-aqueous-air interface. As the vapor diffuses and accumulates into bubbles, the bubbles grow, rupture, and re-nucleate at the interface. Increased hydrocarbon volatility increases the bubble growth rates. The bubbles trap the hydrocarbon vapors with potential benefits in applications including firefighting and oil spills. Also, the fluorine-free surfactants could be made to foam spontaneously by varying the process parameters identified here and could be important in designing environmentally friendly alternatives to per- and poly- fluoroalkyl substances (PFAS). Fluorosurfactants can self-foam from volatile hydrocarbon liquids under specific conditions, which could be adapted to form spontaneous foams from fluorine-free alternatives. All data is available in the manuscript or the supplementary materials. [Display omitted] • A thin hydrocarbon layer floating on aqueous fluorosurfactant spontaneously generates foam at sub-saturation conditions. • Vaporization and diffusion of hydrocarbon nucleates bubbles at the surfactant laden aqueous-hydrocarbon interface. • The vapor diffuses into the bubbles and drives foam growth but also causes bubble rupture and foam degradation. • Fluorosurfactants slow the bubble rupture and foam degradation, which dominates for fluorine-free surfactants. [ABSTRACT FROM AUTHOR]

A new Gemini hybrid surfactant DFCS was prepared to improve salt resistance and interface activity of fluorinated surfactants. This surfactant was expected to be used as a cleanup additive in fracturing and an active agent in water flooding for shale and superlow-permeability sandstone reservoirs. At high salinities, it displayed lower interface tensions than current fluorinated surfactants as well as the obvious non-wettability of water on glass, and the modified natural sandstone surface using DFCS was close to intermediately wetting for the water and oil phases. Also, DFCS exhibited good temperature resistance, and the surface and interface tensions reduced markedly with the temperature below 70 ℃ in water and brine. For DFCS, the molecular area was large, e.g. A CMC = 129.61 Å2 at 30 °C; the micelle formation was entropy-driven, and the spontaneity was stronger than that of reported hybrid surfactants with single −SO 3 − ion. The TEM observation showed that the diameters of mono-molecules and micelles were respectively 3–5 and 20–30 nm for 1.9 g/L (CMC) DFCS in water. It was found by the UV data that the non-polarity in micellar micro-domains was visibly weaker for Gemini hybrid surfactants in comparison to hydrocarbon surfactants and that salt hardly influenced the sizes of their micelles, resulting in good salt resistance. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Prenatal PFOA and PFOS exposures were adversely associated with communication domains of infants at 6 months of age. • PFHxS and 6:2Cl-PFESA were associated with poor scores of communication domain at 6 months. • PFOA, PFOS, and PFHxS can affect the communication domain's trajectory in infancy. • Boys were more sensitive to PFOA, PFOS, and PFHxS than girls. • The impacts of PFAS mixtures were greater than effects induced by individual PFAS. Epidemiological data on the effects of perfluoroalkyl and polyfluoroalkyl substances (PFAS) on infant neurodevelopment trajectories are far from being sufficiently addressed. In this study, 1285 mother–child pairs were recruited during 2016–2017. A high-performance liquid chromatography-triple quadrupole mass spectrometer was used to measure 16 PFAS levels in cord serum. Ages and Stages Questionnaires were used to examine children's neurodevelopment at 2, 6, 12, and 24 months of age. Group-based trajectory models were applied to derive the neurodevelopmental trajectories. Children with relatively low scores from 2 to 24 months were classified into a low-score group and were used as a risk group in each domain. Multiple linear regression, logistic regression, and quantile-based g-computation were performed to assess associations of single or mixture PFAS exposures with neurodevelopment and trajectories. Perfluorooctane sulphonate (PFOS), perfluorooctanoic acid (PFOA), perfluorohexanesulfonic acid (PFHxS), and 6:2 chlorinated polyfluorooctane ether sulfonate (6:2Cl-PFESA) were detected in over 90 % samples. PFOA had the highest concentration (median: 4.61 μg/L). Each ln-unit (μg/L) increase of PFAS (e.g., PFOA, PFOS, PFHxS, 6:2Cl-PFESA) was associated with poor scores of communication domain at 6 months, with the effect size ranging from −0.69 to −0.44. PFOS (OR: 1.14, (1.03, 1.26), PFDA (OR:1.08, (1.02, 1.15)), PFHxS (OR:1.31, (1.12, 1.56)), and 6:2Cl-PFESA (OR:1.08, (1.00, 1.16)) were associated with an increased risk of being in the low-score group in the early childhood communication domain's trajectory. Each mixture quartile increment was associated with a 1.60 (−2.76, −0.45) decrease in communication domain scores of 6-month-old infants, and the mixture effect was mainly attributed to PFOS. Each mixture quartile increase was associated with a 1.23-fold (1.03, 1.46) risk of being in the low-score group of the communication domain, and the mixture effect was mainly attributed to PFOS. In conclusion, PFAS and their mixtures might adversely affect childhood neurodevelopment. The gender-specific associations existed in the above associations. [ABSTRACT FROM AUTHOR]

We report here the synthesis of mesoporous silica materials from various fluorinated-based systems using as the inorganic precursor either sodium silicate solution or silicate ions produced from the dissolution of silica under basic conditions. The properties of the materials are compared with the ones of the mesostructures prepared from tetramethoxysilane as silica source. Results show that whatever the silica source, well-ordered hexagonal materials with a narrow pore size distribution are obtained. Nevertheless, the pH has a great influence on the properties of the recovered materials since it governs the interactions between the surfactant and the inorganic precursor and the pH range for which the hexagonal mesopore ordering is obtained, depends on the silica source. Using sodium silicate, hexagonal mesostructured materials with high specific surface area (≥800 m 2 /g) and narrow pore size distribution (4 nm) are recovered for pH from 0.3 to 5. It should be noted that the formation of organized mesoporous silica under acidic conditions with this precursor is barely reported in literature. Replacing sodium silicate by silica fumed, the pH range leading to a hexagonal mesopore ordering is reduced to 0.3–1.5. When the organosilane is used the ordered mesoporous materials are recovered regardless the pH. In addition in that case a better control of the self assembly between the surfactant and the silica species allows tuning the particles’ morphology. Under acidic conditions tetramethoxysilane gives rise to gyroids or toroids and favors the formation of submicrometer particles, while irregularly shaped particles are produced with sodium silicate or silica fumed under alkaline conditions. Results also show that neither the specific surface area, nor the cell parameter strongly depend on the silica precursor as long as the hexagonal structure is kept. [ABSTRACT FROM AUTHOR]

Two novel polyoxovanadate (POV)-containing fluorosurfactants, each with two hydrophobic fluorinated "tails" and one nanosized, hydrophilic, rigid POV "head group", are synthesized for the first time. They self-assemble into spherical, bilayer vesicles in acetonitrile/water mixed solvents, as evidenced by systemic studies using laser light scattering (LLS) and electron microscopy techniques. The vesicle sizes demonstrate dynamic change over different solvent compositions mainly as a result of the solvent swelling of the fluorocarbon chains, although the charge number on the POVs changes over the solvent polarity as well. [ABSTRACT FROM AUTHOR]

A pore-lining coating method for marble stone surfaces based on the fluorosurfactant Capstone FS-63 has been optimized for application through spray coating by tuning the solvent composition. The optimized application conditions showed an effective penetration depth of the hydrophobic properties down to at least 0.5 mm, ensuring a long-term protection against water uptake. Mechanistic studies of the functionalization process revealed that the solution mixtures containing ethylene glycol provide the best pore-lining functionalization, due to the prolonged functionalization time as a consequence of the slow evaporation rate of the solvent combined with the beneficial shift in the surfactant-vesicle equilibrium towards free surfactants. The coatings also display anti-graffiti properties, allowing for graffiti paint to easily be washed away with a standard pressure washer repeatedly 3–4 times. For optimal re-usability of the anti-graffiti coatings, a new coating can be applied when the first coating loses its effectiveness. [ABSTRACT FROM AUTHOR]

A robust and efficient interconnection layer (ICL) based on low conductive poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) and ZnO nanoparticles is implemented in a solution-air-processed, blade coated inverted polymer tandem solar cell. The commercial PEDOT:PSS (Heraeus Clevios P VP Al 4083) is modified with a fluorosurfactant to allow its deposition onto any hydrophobic active layer surface. However, this method alters the electrical and energetic properties of the PEDOT:PSS thus affecting the interface with the ZnO layer, responsible for an inefficient ICL and poorly performing tandem devices. The ohmic contact at the PEDOT:PSS/ZnO interface is successfully optimized through a simple solvent treatment of the PEDOT:PSS film surface, leading to tandem devices with power conversion efficiencies (PCEs) improved by more than 50% compared to the untreated reference system. The reported method is an easy and versatile approach to optimize the functionality of the PEDOT:PSS/ZnO ICL of inverted multijunction devices, applicable onto any organic active layer and compatible with a roll-to-roll production line. [ABSTRACT FROM AUTHOR]

Per- and polyfluoroalkyl substances (PFAS) are persistent organic pollutants widely contaminated and exposed in humans. China is a major manufacturer and consumer of these chemicals. To characterize the occurrences, geographical variations, temporal trends, and exposure risks of legacy and emerging PFAS in perinatal women and their children in China, 30 PFAS were measured in 100 pooled human milk samples consisting of 3531 individual samples collected from 100 sites in 24 provinces during the 2017–2020 National Human Milk Survey. Linear-perfluorooctanoic acid (L -PFOA, 151 pg/mL) and linear-perfluorooctane sulfonate (L -PFOS, 57.0 pg/mL) were the predominant PFAS in human milk, followed by 6:2 chlorinated polyfluorinated ether sulfonate (6:2 Cl-PFESA, 25.9 pg/mL). The geographic variation trend of PFOA was different from PFOS and Cl-PFESA, and a special geographic trend of perfluoropentanesulfonate (PFPeS) was observed. Comparison of National Human Milk surveys from different periods showed a sharp decrease of PFAS exposure in old industrial areas including Shanghai and Liaoning, but higher PFAS exposure observed in Shandong and Hubei indicated a possible domestic shift of PFAS manufacture to these areas. Worldwide comparison of PFAS in human milk indicated high PFOA exposure in China. Risk assessments for mothers and breastfeeding infants showed that PFAS exposure is of concern in China. [Display omitted] • National wide distribution of the Legacy and emerging PFAS was revealed. • 6:2 Cl-PFESA occurred at relatively high levels and high detection rate. • Geographic variations and temporal trend of PFAS across nationwide areas were explored. • Potential hazard from PFAS exposure, especially from high PFOA exposure, was observed. [ABSTRACT FROM AUTHOR]

Perfluorooctane sulfonate (PFOS) and its alternative 6:2 chlorinated polyfluorinated ether sulfonate (6:2 Cl-PFESA) are ubiquitous in various environmental and human samples. They have been reported to have hepatotoxicity effects, but the potential mechanisms remain unclear. Herein, we integrated metabolomics and proteomics analysis to investigate the altered profiles in metabolite and protein levels in primary human hepatocytes (PHH) exposed to 6:2 Cl-PFESA and PFOS at human exposure relevant concentrations. Our results showed that 6:2 Cl-PFESA exhibited higher perturbation effects on cell viability, metabolome and proteome than PFOS. Integration of metabolomics and proteomics revealed that the alteration of glycerophospholipid metabolism was the critical pathway of 6:2 Cl-PFESA and PFOS-induced lipid metabolism disorder in primary human hepatocytes. Interestingly, 6:2 Cl-PFESA-induced cellular metabolic process disorder was associated with the cellular membrane-bounded signaling pathway, while PFOS was associated with the intracellular transport process. Moreover, the disruption effects of 6:2 Cl-PFESA were also involved in inositol phosphate metabolism and phosphatidylinositol signaling system. Overall, this study provided comprehensive insights into the hepatic lipid toxicity mechanisms of 6:2 Cl-PFESA and PFOS in human primary hepatocytes. [Display omitted] • Comparison of the metabolite and protein profiles of 6:2 Cl-PFESA and PFOS in primary human hepatocytes. • 6:2 Cl-PFESA and PFOS significantly altered glycerophospholipid metabolism processes in PHH cells with distinct mechanism. • 6:2 Cl-PFESA exhibited higher perturbation effects on cellular membrane function than PFOS in PHH cells. [ABSTRACT FROM AUTHOR]

Perfluorobutane sulfonate (PFBS), an alternative to perfluorooctane sulfonate (PFOS), has been increasingly used in recent years. However, emerging evidence has raised concerns about the potential health risks of PFBS. Here, the toxicityof low-dose PFBS on livers was explored and compared with that of PFOS. Adult C57BL/6 mice were exposed to 10 μg/L, 500 μg/L PFBS, or 500 μg/L PFOS for 28 days through drinking water. At the phenotypic level, no liver damage was observed in the 10 μg/L PFBS group. The cell apoptosis and decrease of CAT activities were observed in the 500 μg/L PFBS group, while accumulation of lipid droplets, increase of CAT activities and TAG levels were found in the 500 μg/L PFOS group. Lipidomics analysis revealed that 138, 238, and 310 lipids were significantly changed in the 10 μg/L, 500 μg/L PFBS and 500 μg/L PFOS groups, respectively. The two PFBS-treated groups induced similar global lipid changes in a dose-dependent manner, which were distinct from PFOS. Overall, PFBS exposure induced an increase in phosphatidylcholines and sphingomyelins, but a decrease in phosphatidylinositol. PFOS exposure caused an increase in triacylglycerols. This study provides more evidence on the health hazards caused by exposure to low-dose PFBS. [Display omitted] • Adverse effects of low-dose PFBS and PFOS on mouse livers were compared. • No liver damage was observed at the phenotypic level after 10 μg/L PFBS exposure. • Exposure of 500 μg/L PFBS and PFOS induced liver damage. • Lipidomic profiles induced by PFBS were different from those of PFOS. • PFBS exposure altered abundance of phosphatidylcholines, sphingomyelins, and phosphatidylinositols. [ABSTRACT FROM AUTHOR]

The transport behavior of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) in porous media controls their final environmental fate and risk. Current work used column experiments and a two-site kinetic retention model to reveal the effect of dissolved organic matter (DOM) on their migration under the interference of solution ionic strength and cation type. Results showed the migration of PFOA and PFOS was inhibited by 1 mg/L DOM but promoted by 10 mg/L DOM. Compared with the presence of 1 mg/L DOM, increasing ionic strength (1–10 mM) and changing cation type (Na+ to Ca2+) had a stronger inhibitory effect on PFOS transport. However, the opposite is true for PFOA due to its different molecular structure and adsorption behavior from PFOS. Ca2+ was more tended to interact with PFOS (owing to its sulfonate group) than with PFOA, and PFOS had a higher affinity with Ca2+ than with DOM. Cation bridging and increasing ionic strength could promote the inhibition of PFOA and PFOS transport by 1 mg/L DOM. The influence of DOM on PFASs transport could be very complex in the natural environment due to the variable solution chemistry conditions of pore water and physico-chemical properties of PFASs. The results of this work have scientific significance for better evaluating and managing the environmental risk of soil PFASs. [Display omitted] • DOM-mediated transport of PFOA and PFOS is solution chemistry dependent. • PFOA and PFOS transport was inhibited by deposited DOM but facilitated by free DOM. • The DOM-affected transport of PFOA was less disturbed by ionic strength and Ca2+. • PFOS preferred to interact with Ca2+ rather than DOM. • Ca2+ and higher ionic strength promoted the effect of deposited DOM. [ABSTRACT FROM AUTHOR]

CFSONH(CH)N(CH)(CHCOO)Na (PNHD) is a novel amphoteric fluorinated surfactant. The corrosion inhibition of PNHD and its mixed systems with cetyl trimethylammonium bromide (CTAB) or octylphenol ethoxylate 9.5 EO (TX-10) for carbon steel Q235 in 1.0 M HCl solution was studied in this paper. The corrosion inhibition efficiency ( η) was determined by weight loss, electrochemical methods and scanning electron microscope. The values of η from the three methods were almost identical. The hydrophilic head group of PNHD has two lone pairs of electrons at the nitrogen atoms, suggesting a chemisorption mechanism between carbon steel and surfactant. The PNHD and mixed systems inhibitors acted as a mixed inhibitor; there is interaction between PNHD and CTAB or TX-100. A compact protective film was formed in PNHD and its mixed systems. [ABSTRACT FROM AUTHOR]

Potassium perfluorooctane sulfonate (KPFOS) and sodium perfluorooctane sulfonate (NaPFOS) exhibit poor surface activities in aqueous solution at room temperature because of their high Krafft points. In this work, we attempted to increase the solubility of KPFOS and NaPFOS and consequently improve their surface activities at room temperature with sodium p-methylbenzene sulfonate (BS) and urea, which are typical hydrotropes in industrial applications. The effects of BS and urea on the surface tension of the aqueous solutions of KPFOS and NaPFOS were investigated at 25 °C. When the hydrotropes were added, the effectiveness of KPFOS and NaPFOS in surface tension reduction was greatly enhanced and KPFOS showed higher efficiency in surface tension reduction than NaPFOS. On the other hand, BS had much stronger ability than urea to reduce the surface tension of KPFOS and NaPFOS in water. In particular, with the assistance of BS the minimum surface tension of KPFOS approached 19 mN/m at 25 °C. It was worth noting that in the presence of BS, the surface tension of an apparently 'saturated' solution (i.e., with coexisting surfactant solid) continuously decreased with increasing surfactant concentration. This behavior was ascribed to enrichment of branched PFOS isomers in aqueous phase with the assistance of BS, as evidenced by high-resolution F NMR. Hydrotropes were able to recover the inherent character of KPFOS and NaPFOS as highly surface-active fluorinated surfactants by increasing the solubility of branched isomers. This is an easy way to enhance the effectiveness in surface tension reduction at room temperature for fluorinated surfactants with high Krafft points. [ABSTRACT FROM AUTHOR]

ABSTRACT Perfluorooctanoic acid (PFOA) is a widespread environmental contaminant that induces developmental cardiotoxicity. It is detectable in late stage chicken embryos and hatchling chickens. To investigate mechanism(s) of cardiotoxicity, primary cultures of cardiomyocytes were prepared from 10-day-old chicken embryos that were (A) pre-exposed to vehicle or 2 mg of PFOA/kg of egg weight in ovo or (B) incubated with PFOA in vitro at concentrations ranging from 0 to 100 µg/mL in medium for 1 or 36 h. When viability was assessed, survival of cardiomyocytes prepared from pre-exposed embryos did not differ from vehicle controls, even under conditions of serum starvation designed to challenge the cells. However, 1 h of exposure to 100 µg/mL of PFOA in vitro and 36 h of exposure to 75 and 100 µg/mL PFOA in vitro decreased viability. When contractility was evaluated, cardiomyocytes cultured from pre-exposed embryos exhibited decreases in time to maximum departure velocity and cell length at peak contraction, whereas cardiomyocytes exposed in vitro exhibited a reduction in the 50% relaxation time at a concentration of 1 µg/mL relative to vehicle controls. Morphological assessment revealed decreased cardiomyocytes axial length following in ovo PFOA exposure and 24 h in vitro PFOA 50 µg/mL exposure. Reactive oxygen species (ROS) generation, which was evaluated only in cardiomyocytes exposed to PFOA in vitro, was significantly elevated following incubation with 50 µg/mL of PFOA for 1 h. These data indicate that while in vitro exposure to relatively high concentrations of PFOA can induce cytotoxicity and ROS, developmental cardiotoxicity observed in ovo is not likely mediated via PFOA-induced overt cytotoxicity, but likely by altering early cardiac morphologic and function processes. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1580-1590, 2016. [ABSTRACT FROM AUTHOR]

Understanding the adsorption behavior of fluorinated surfactants at air/liquid interfaces are important in many academic and industrial applications. Most surfactants contain spacers, which are employed to separate and link the hydrophobic/hydrophilic groups. In this work, molecular dynamics (MD) simulations were employed to investigate the microscopic structure of perfluorooctane sulfonate (PFOS) with different spacer at the air/liquid interface. The influence of different spacer on the interfacial structure and hydrophilicity of the head group were investigated as well. The relationship between the component of the spacer and the surface activity of surfactants is revealed. It is found that the orientation and conformation of hydrophobic chains in surfactants would not be influenced much when some functional groups are employed as spacers. While the hydrophilicity of the head group would be improved by introducing hydrophilic groups as spacers. The amide(CONH) group performs better than other functional groups. [ABSTRACT FROM AUTHOR]

The principle limitation of perovskite solar cells is related to their instability and, hence, their limited lifetime. Herein, we employ an imidazolium iodide dopant, 1-methyl-3-(1H,1H,2H,2H-nonafluorohexyl)-imidazolium iodide, containing a perfluorous appendage, which leads to prolonged (unencapsulated, under Ar atmosphere) device activities exceeding 100 days without compromising the power conversion efficiency and other photovoltaic parameters. The extended lifetime of the device can be attributed, at least in part, to the hydrophobic nature of the imidazolium iodide salt. The functionalization of the perovskite material was found to have negligible influence on the perovskite crystal structure. [ABSTRACT FROM AUTHOR]

The treatment of fluorosurfactant-containing wastewater is still challenging nowadays. Here, a method is presented to remove fluorosurfactants from water, amongst others from electroplating wastewater. This elimination technique is based on the generation of gas bubbles in solution, enrichment and scavenging of fluorosurfactants by transport of the gas bubbles to the water surface. Finally the bubbles collapse and release an aerosol which is enriched with fluorosurfactants. By sampling of the released aerosols a mass balance was established for 6:2 fluorotelomer sulfonic acid (6:2 FTSA). Thereby 99.8% of the initial amount was revocered in the collected aerosols. Fluorosurfactant concentration in solution decreased exponentially with half-lives ranging from 2 to 6 min for 6:2 FTSA as well as perfluorooctane carboxylate (PFOA) and perfluorooctane sulfonate (PFOS). Elimination rate in defined matrix (0.2 M H 2 SO 4 ) within 60 min was 99.6, 99.9 and 99.8% for 6:2 FTSA, PFOA and PFOS, respectively. The removal rate of 6:2 FTSA increased in solutions with higher ionic strength. Different wastewater from an electroplating industry containing 6:2 FTSA was treated with the described method without any sample pre-treatment and elimination of 6:2 FTSA took place with the same effectiveness as in synthetic matrices. [ABSTRACT FROM AUTHOR]

A facile in situ and UV printing process was demonstrated to create self-cleaning synthetic replica of natural petals and leaves. The process relied on the spontaneous migration of a fluorinated acrylate surfactant (PFUA) within a low-shrinkage acrylated hyperbranched polymer (HBP) and its chemical immobilization at the polymer-air interface. Dilute concentrations of 1 wt. % PFUA saturated the polymer-air interface within 30 min, leading to a ten-fold increase of fluorine concentration at the surface compared with the initial bulk concentration and a water contact angle (WCA) of 108°. A 200 ms flash of UV light was used to chemically crosslink the PFUA at the HBP surface prior to UV printing with a polydimethylsiloxane (PDMS) negative template of red and yellow rose petals and lotus leaves. This flash immobilization hindered the reverse migration of PFUA within the bulk HBP upon contacting the PDMS template, and enabled to produce texturized surfaces with WCA well above 108°. The synthetic red rose petal was hydrophobic (WCA of 125°) and exhibited the adhesive petal effect. It was not superhydrophobic due to insufficient concentration of fluorine at its surface, a result of the very large increase of the surface of the printed texture. The synthetic yellow rose petal was quasi-superhydrophobic (WCA of 143°, roll-off angle of 10°) and its self-cleaning ability was not good also due to lack of fluorine. The synthetic lotus leaf did not accurately replicate the intricate nanotubular crystal structures of the plant. In spite of this, the fluorine concentration at the surface was high enough and the leaf was superhydrophobic (WCA of 151°, roll-off angle below 5°) and also featured self-cleaning properties. [ABSTRACT FROM AUTHOR]

In gas condensate reservoir, liquid condensation near the wellbore region might kill gas well deliverability, research shows that gas-wetting alteration can be one of effective methods to alleviate liquid condensation in porous media. However, the wettability of cores can only be altered from liquid-wetting to intermediate gas-wetting, making the improvement for gas well deliverability very limited. To achieve super gas-wetting alteration, nano-silica was modified functionally by the fluorosurfactant FG40. To evaluate the influence of gas-wetting alteration on cores, the contact angle measurement, Owens two-liquid method, capillary rise, and imbibition spontaneous tests in the CH 4 -liquid-core system were conducted, respectively. The results showed that the wettability of the core can be altered to intermediate gas-wetting or super gas-wetting after treatment by the FG40, FP-2, and FG40 modified nano-silica. The contact angles of the brine and decane on the core surface increased from 23° and 0° to 152° and 127°, respectively, after the 0.5% FG40 modified nano-silica treatment; these angles are obviously higher than in those cores treated with FG40 and FP-2 solutions at an equivalent concentration. Meanwhile, the surface free energy of the cores sharply decreased from about 70 mN/m to approximately 0.61 mN/m after the FG40 modified nano-silica treatment. The results of the capillary rise and imbibition tests were also consist with that of the contact angle measurement; the liquid levels of brine and decane significantly decreased from 27 and 13.5 mm to −20 and −7 mm, respectively, after treatment by the FG40 modified nano-silica solution. The imbibition of brine and oil in the core also decreased sharply due to the super gas-wetting alteration. Results of scanning electron microscopy (SEM) and transmission electron microscopy (TEM) demonstrated that the botryoidal structure of gas-wetting particles plays a vital role in gas-wetting alteration, which can alter the wettability of the core from strong liquid-wetting to super gas-wetting. [ABSTRACT FROM AUTHOR]