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Millions of people in poor areas are still under the threat of fluoride contamination. How to effectively separate fluorine in water is an important step to reduce the ecological risk. In this paper, we performed a systematic DFT calculation focused on the defluorination behavior between the LiAl- and MgAl-LDHs. The results indicated that the LiAl-LDHs exhibited high chemical activity before the defluorination, because of the better electronic structure. After the defluorination, the LiAl-LDHs with adsorbed-F

Amyloidosis, commonly known as amyloid-associated diseases, is characterized by improperly folded proteins accumulating in tissues and eventually causing organ damage, which is linked to several disorders ranging from neurodegenerative to peripheral diseases. It has an enormous societal and financial impact on the global health sector. Due to the complexity of protein misfolding and intertwined aggregation, there are no effective disease-modifying medications at present, and the condition is likely mis/non-diagnosed half of the time. Nonetheless, over the last two decades, substantial research into aggregation processes has revealed the possibilities of new intervention approaches. On the other hand, fluorine has been a rising star in therapeutic development for numerous neurodegenerative illnesses and other peripheral diseases. In this study, we revised and emphasized the possible significance of fluorine-modified therapeutic molecules and fluorine-modified nanoparticles (NPs) in the modulation of amyloidogenic proteins, including insulin, amyloid beta peptide (Aβ), prion protein (PrP), transthyretin (TTR) and Huntingtin (htt).

CRISPR/Cas9 gene-editing technology shows great potential for treating a variety of diseases, such as glioblastoma multiforme (GBM). However, CRISPR components suffer from inherent delivery challenges, such as poor in vivo stability of Cas9 protein and gRNA, low blood-brain barrier (BBB) permeability and non-specific tissue or cell targeting. These defects have limited the application of Cas9/gRNA ribonucleoprotein (RNP) complexes for GBM therapy. Here, we developed a brain-targeted CRISPR/Cas9 based nanomedicine by fabricating an angiopep-2 decorated, guanidinium and fluorine functionalized polymeric nanoparticle with loading Cas9/gRNA RNP for the treatment of GBM. The guanidinium and fluorine domains of our polymeric nanoparticles were both capable of interacting with Cas9/gRNA RNP to stabilize it in blood circulation, without impairing its activity. Moreover, by leveraging angiopep-2 peptide functionality, the RNP nanoparticles efficiently crossed the BBB and accumulated in brain tumors. In U87MG cells, we achieved approximately 32% gene knockout and 67% protein reduction in the targeted proto-oncogene polo-like kinase 1 (PLK1). This was sufficient to suppress tumor growth and significantly improved the median survival time of mice bearing orthotopic glioblastoma to 40 days, while inducing negligible side or off-target effects. These results suggest that the developed brain-targeted CRISPR/Cas9 based nanomedicine shows promise for effective human glioblastoma gene therapy.

In this work, nitrogen and fluorine co-doped porous carbon nanosheets (NFPCNS) were fabricated from pharmaceutical drug residues derived from the fermentation synthesis of lincomycin hydrochloride via high-temperature pyrolysis and subsequent KOH activation without adding any nitrogen and fluorine reagents. The obtained NFPCNS exhibits an optimized integration of three dimensional interconnected nanosheet structure, large specific surface area of 2912 m

To investigate the role and molecular mechanism of estrogen deficiency in fluorine ion (F

Both sulfur and fluorine play important roles in organic synthesis, the life science, and materials science. The direct incorporation of these elements into organic scaffolds with precise control of the oxidation states of sulfur moieties is of great significance. Herein, we report the highly selective electrochemical vicinal fluorosulfenylation and fluorosulfoxidation reactions of alkenes, which were enabled by the unique ability of electrochemistry to dial in the potentials on demand. Preliminary mechanistic investigations revealed that the fluorosulfenylation reaction proceeded through a radical-polar crossover mechanism involving a key episulfonium ion intermediate. Subsequent electrochemical oxidation of fluorosulfides to fluorosulfoxides were readily achieved under a higher applied potential with the adventitious H2O in the reaction mixture.

Magnesium batteries are one of the most promising post-lithium technologies. One of the main challenges preventing its commercialization is to find an efficient and safe electrolyte. The electrolyte, playing the role of the blood in a battery, interacts with all battery components and must be highly compatible with all of them. The development of Cl-free electrolyte systems is desired to avoid corrosion issues, and many studies suggest magnesium tetrakis(hexafluoroisopropyloxy)borate (Mg[B(hfip)4]2) as one of the best candidates in terms of electrochemical properties and chemical stability. Here we present an in-depth analysis of the unique structure of this salt and the interactions generated in the electrolyte among the dissociated ions. The results show a delicate balance between electron-withdrawing effects and ligand stabilization in B(hfip)4−, crucial from the point of view of magnesium electrolytes. Moreover, the bulk nature of B(hfip)4− limits the anion-cation contacts to infrequent interactions through fluorine atoms. This has consequences not only for ion transport but also for hindering the anion decomposition towards the formation of MgF2. Taken together, we managed to demystify the exclusive nature of B(hfip)4− anion, thereby allowing for further rational development of new anion structures.

The super-structured nanodimensional apatitic particles have been limited explored for therapeutic applications. Furthermore, ion substituted super-structured nanodimensional apatitic particles have been rarely attempted, which motivated the present investigation. In the present work, F − and Cl − substituted hydroxyapatite (HAP) prepared via a facile and economical one-pot hydrothermal route were characterized for their structural, morphological and bioactive properties. The F − and Cl − anions (1 wt%) were individually substituted in hierarchically assembled nanostructured apatitic (HANA) particles and produced fluorine substituted Hydroxyapatite (FHAP) and chlorine substituted Hydroxyapatite (ClHAP) HANA particles, respectively. Besides comprehensive characterization, particles were systematically tested for their in-vitro ionic dissolution and drug-carrying abilities. Both FHAP and ClHAP nanoparticles exhibited monolithic apatitic structure, novel spherical morphology having substituted elements, mesoporous large surface area, and pore-volume with high thermal stability. Furthermore, both particles exhibited superior in-vitro bioactivity ability. Besides it, both FHAP and ClHAP nanoparticles exhibited superior drug loading and sustained drug release characteristics. Thus, this study presented the potentials of novel particle shapes with superior bioactivity and drug-carrying abilities, making them suitable for multipurpose therapeutic applications, including tissue regeneration and drug-carrying agents.

Selective functionalization of C–F bonds in trifluoromethyl groups has recently received a growing interest, as it offers atom- and step-economic pathways to access highly valuable mono- and difluoroalkyl-substituted organic molecules using simple and inexpensive trifluoromethyl sources as the starting materials. In this regard, impressive progress has been made on the defluorinative functionalization reactions that proceed via radical intermediates. Nevertheless, it is still a great challenge to precisely control the defluorination process, due to the continuous decrease of the C–F bond strength after the replacement of one or two fluorine atoms with various functionalities. This review article is aimed to provide a brief overview of recently reported methods used to functionalize C–F bonds of CF3 groups via radical intermediates. An emphasis is placed on the discussion of mechanistic aspects and synthetic applications

In this review, the methodologies for fluorine incorporation of 40 fluorine-containing agrochemicals that received an international standardization organization (ISO) name during the last decade are described. The predominant approach for fluorine introduction of these agrochemicals is to use a fluorine-containing building block. Here we present how the fluorine-containing building blocks are introduced into these agrochemicals. The synthetic methods of fluorine-containing building blocks that are not easily available are also specifically discussed. Fluoroarenes, difluomethylarenes and trifluomethylarenes are the main building blocks that have been used in this review. Fluorine-containing small molecules, such as alcohol, amine, ketoester, olefin, etc., are also widely used. The only example of late-stage fluorination is the synthesis of fungicide quinofumelin. We believe the fluorine introduction methods described here can provide ideas for the development of new and economical pesticide synthetic routes, and stimulate researchers to develop new fluorine incorporation methods and create new pesticides.

To obtain superior surface-active properties while minimizing environmental risks, new fluorinated surfactants (F2HX-nEO) were designed to include a hybrid multi-chain with a short fluorocarbon (–CF2CF3) and nonionic ethylene oxide. They were simply synthesized by a straightforward reaction involving the addition of ethylene oxide to a hybrid fluorine alcohol, and their surface-active properties were optimized by controlling the hydrocarbon length and number of ethylene oxide units. Therefore, the desirable values of critical micelle concentration (0.3 mmol/L) and surface tension (24.3 mN/m) were obtained in spite of containing the short fluorocarbon chain. Particularly, F2HX–nEO showed excellent wetting properties on hydrophobic surfaces and very low toxicity level, which can be used in various fields as a promising alternative to long fluoroalkyl chain surfactants.

A physicochemical mechanism acting between the reactive plasma and the material surface controls the erosion of polycrystalline ceramics in fluorine containing etching plasmas. In this study, a Y2O3/YOF composite was exposed to a fluorine etching plasma. Relocalization enables the direct correlation of crystalline orientation with material response. Our study reveals an orientation dependent surface fluorination of Y2O3, which controls the etching resistance and morphology formation. Orientations near the low index planes (001), (010) and (100) exhibit the lowest stability due to a homogeneous surface reaction. The presented results help to extend the mechanistic understanding of the plasma-material interaction of Y2O3.

An ultra-active metal-free ORR electrocatalyst (F–N-AC-1000) was developed by fluorine doped N-based activated carbon. The as-prepared F–N-AC-1000 exhibited half-wave potentials of 0.89 V and 0.75 V (vs. RHE) in alkaline and acidic electrolytes, respectively, which are both among the most active metal-free ORR catalysts reported in the literature. F–N-AC-1000 also showed much higher methanol tolerance and stability than the commercial Pt/C catalyst. Experimental and theoretical calculation results demonstrated a novel viewpoint on synergistic effect that the superior ORR performance could be mainly ascribed to the incorporation of fluorine atom into the pyridinic-N configuration, and the charge and spin densities of the adjacent C atoms (Lewis base site) were significantly improved in comparison with the absolute pyridine structure. High ORR performance was attributed to the enhanced Lewis base site rather than the increase of the total content of active sites at the location of the doped fluorine and nitrogen atoms. The hierarchical pore structure with large specific surface area could supply more available active sites and provide fast transport channel for electrons and products. This study will provide useful guidance for the design of superior metal-free ORR catalysts, promoting the application of metal-free carbon-based catalysts in batteries or fuel cells.

Design and synthesis of low bandgap (LBG) polymer donors is inevitably challenging and their processability from a non-halogenated solvent system remains a hurdle to overcome in the area of high-performance polymer solar cells (PSCs). Due to a high aggregation tendency of LBG polymers, especially diketopyrrolopyrrole (DPP)-based polymers coupled with bithiophenes in the polymer backbones, their widespread adoption in non-halogenated solvent-processed PSCs has been limited. Herein, a novel LBG DPP-based polymer, called PDPP4T-1F with asymmetric arrangement of fluorine atom, has been successfully synthesized and showed an outstanding power conversion efficiency (PCE) of 10.10% in a single-junction fullerene-based PSCs. Furthermore, an impressive PCE of 13.21% has been achieved in a tandem device from a fully non-halogenated solvent system, which integrates a wide bandgap PDTBTBz-2F polymer in the bottom cell and LBG PDPP4T-1F polymer in the top cell. The achieved efficiency is the highest value reported in the literature to date in fullerene-based tandem PSCs. We found that a uniformly distributed interpenetrating fibril network with nano-scale phase separation and anisotropy of the polymer backbone orientation for efficient charge transfer/transport and suppressed charge recombination in PDPP4T-1F-based PSCs led to outstanding PCEs in single and tandem-junction PSCs.

Developing metal-organic framework (MOF)-based materials with good cyclic stability is the key to their practical application. Fluorinated organic compounds are usually highly chemically stability due to the high electronegativity of fluorine. Also, the pillared-layer structures based on coordination bonds have better structure and thermal stability than those based on hydrogen bonds. Herein, the fluorinated pillared-layer [Ni(2,3,4,5-tetrafluorobenzoic acid)(4,4′-bipyridine)]n MOF ([Ni(TFBA)(Bpy)]n) materials were constructed through a facile room-temperature solution reaction and used as electrode materials for supercapacitors. Surprisingly, the size/morphology of Ni(TFBA)(Bpy)]n MOFs could be adjusted by varying the synthesis time. Benefting from the short ion diffusion length, unique pillar-layer structure, and strong intercomponent synergy of organic ligands, the Ni(TFBA)(Bpy)]n MOF microrods showed a higher electrochemical energy storage capability than bulk MOFs. At the same time, compared to the non-fluorinated [Ni(benzoic acid)(Bpy)]n MOFs (31.5% capacitance decay), the fluorinated Ni(TFBA)(Bpy)]n MOFs have a higher cycle stability with only 2.6% capacitance loss after 5000 cycles at 3 mA/cm2.

Hydrogenation of aromatics by catalytic hydroprocessing is necessary in the upgrading of fossil hydrocarbons into fuels and bases for petrochemistry. In this paper the meaning and applicability are discussed of the “rim-edge” model, the outstanding hydrogenation activities of NiMoS supported on NiSx, and the effect of doping by the hard anion-forming elements phosphorous, boron, and fluorine.

The exploitation of high energy and high power densities cathode materials for sodium ion batteries is a challenge. Na-super-ionic-conductor (NASICON) Na4MnV(PO4)3 is one of promising high-performance and low-cost cathode materials, however, still suffers from not reaching the theoretical capacity, low rate capability, and poor cycling stability. In this work, we deploy a novel sodium-deficient NASICON fluorinated phosphate cathode material for sodium ion batteries which demonstrates, notably, high energy and high power densities concomitant with high sodium diffusion kinetics. The enhanced performance of this novel Na3.85⬜0.15MnV(PO3.95F0.05)3 cathode was evidenced by demonstrating a relatively high energy density of ∼380 Wh kg−1 at low rate with much improved rate capability compared to non-doped Na4MnV(PO4)3, and long cycling life over 2000 cycles at high current rates. The structural investigation during battery operation using in situ x-ray diffraction (XRD) reveals bi-phase mechanism with high structural reversibility. The combined XRD and 23Na nuclear magnetic resonance (NMR) analyses demonstrate that the sodium extraction/insertion from Na2 is faster than Na1 site. These findings open promising prospects for unlocking of high energy and high power densities of NASICON phosphate materials by fluorine substitution towards high-performance sodium ion batteries.

Fluorine-doped graphene quantum dots have unique chemical bonds and charge distribution, which can bring unexpected properties compared to other common atom-doped graphene quantum dots. In the present work, fluorine and nitrogen co-doped graphene quantum dots (F, N-GQDs) are synthesized from levofloxacin via a simple hydrothermal method. Systematic studies demonstrate that F, N-GQDs can emit various fluorescence with the wavelength ranging from blue to green by dispersing F, N-GQDs into different solvents. Moreover, multi-color fluorescence is available by simply changing the concentration of F, N-GQDs. In addition to these unique characteristics, F, N-GQDs also exhibit a sensitive fluorescence response to tetracycline with an ultralow detection limit of 77 nM in water. Because of high photostability and high quantum yield, the F, N-GQDs are exploited as a unique invisible ink, which is printable and writable on paper. Meanwhile, based on the solvatochromism of F, N-GQDs, we realized the color adjustable fluorescent ink. Finally, large-area flexible multi-color fluorescent films are realized. Our synthesized F, N-GQDs, with tunable fluorescence in wavelength and intensity, have numerous opportunities for optical molecular sensors, information security, flexible optics, and others.

Up to date, solid-state carbon dots (CDs) with bright red fluorescence have scarcely achieved due to aggregation-caused quenching (ACQ) effect and extremely low quantum yield in deep-red to near infrared region. Here, we report a novel fluorine-defects induced solid-state red fluorescence (λem = 676 nm, the absolute fluorescence quantum yields is 4.17%) in fluorine, nitrogen and sulfur co-doped CDs (F,N,S-CDs), which is the first report of such a long wavelength emission of solid-state CDs. As a control, CDs without fluorine-doping (N,S-CDs) show no fluorescence in solid-state, and the fluorescence quantum yield/emission wavelength of N,S-CDs in solution-state are also lower/shorter than that of F,N,S-CDs, which is mainly due to the F-induced defect traps on the surface/edge of F,N,S-CDs. Moreover, the solid-state F,N,S-CDs exhibit an interesting temperature-sensitive behavior in the range of 80–420 K, with the maximum fluorescence intensity at 120 K, unveiling its potential as the temperature-dependent fluorescent sensor and the solid-state light-emitting device adapted to multiple temperatures.

Hypothesis: Smart membranes with robust liquid water resistance and water vapor transmission capabilities have attracted growing attentions in personal protective equipment and environmental protection. However, current fluorine-free waterproof and breathable nanofibrous membranes are usually prepared through toxic solvent-based electrospinning, which raises great concerns about their environmental impacts. Experiments: We develop environmentally friendly fluorine-free polyurethane nanofibrous membranes with robust waterproof and breathable performances via waterborne electrospinning without post-coating treatment. The incorporation of the low surface energy long-chain alkyls and polycarbodiimide crosslinker imparts the interconnective porous channels with high hydrophobicity to waterborne fluorine-free polyurethane nanofibrous membranes. Findings: The waterborne fluorine-free nanofibrous membranes show high water contact angle of 137.1°, robust hydrostatic pressure of 35.9 kPa, desirable water vapor transmission rate of 4885 g m−2 d-1, excellent air permeability of 19.9 mm s−1, good tensile elongation of 372.4%, and remarkable elasticity of 56.9%, thus offering strong potential for protective textiles and leaving no toxic solvent residues. This work could also serve as a guide for the design of green and high-performance fibrous materials used for medical hygiene, wearable electronics, water desalination, and oil/water separation.

Ni-rich layered oxide LiNixCoyMn1-x-yO2 (x ≥ 0.8) is the most promising cathodes for future high energy automotive lithium-ion batteries. However, its application is hindered by the undesirable cycle stability, mainly due to the irreversible structure change at high voltage. Herein, we demonstrate that F substitution with the appropriate amount (1 at%) is capable for improve the electrochemical performance of LiNi0.9Co0.05Mn0.05O2 cathode significantly. It is revealed that F substitution can reduce cation mixing, stabilize the crystal structure and improve Li transport kinetics. The resulted LiNi0.9Co0.05Mn0.05O1.99F0.01 cathode can deliver a high capacity of 194.4 mAh g−1 with capacity retention of 95.5% after 100 cycles at 2C and 165.2 mAh g−1 at 5C. In-situ synchrotron X-ray technique proves that F ions in the cathode materials can suppress the irreversible phase transition from H2 phase to H3 phase in high voltage region by preventing oxygen gliding in a-b planes, ensuring a long-term cycle stability.

Point-defect engineering is an effective way to control the mobility and transparent-conducting performance of sputtered fluorine-doped ZnO (FZO) thin films. In this study, doping with fluorine (F) is accomplished through a simple one-step deposition process and is demonstrated to enhance the crystal quality, eliminate the point defects, and boost the mobility as well as the performance of the films. Furthermore, the films’ characteristics are observed to be strongly dependent on F content. At the optimum F content of 1%, the FZO films exhibited the best crystal quality and the lowest concentration of Zn interstitial and O vacancy defects due to F passivation. Moreover, a mobility as high as 45.3 cm2/V and the greatest figure-of-merit performance are achieved for cutting-edge transparent electrode applications. However, a further increase of F content brought about an increased concentration of defects relating to Zn vacancies, especially F interstitials, which yielded the low mobility and poor performance due to the degraded structure.

O3-type NaNiO2-based cathode materials undergo irreversible phase transition and serious capacity decay at high voltage above 4.0 V in sodium-ion batteries. To address these challenges, effects of F-substitution on the structure and electrochemical performance of NaNi0.4Mn0.25Ti0.3Co0.05O2 are investigated in this article. The F-substitution leads to expanding of interlayer, which can enhance the mobility of Na+. NaNi0.4Mn0.25Ti0.3Co0.05O1.92F0.08 (NMTC-F0.08) with the optimal F-substitution degree exhibits much improved rate capability and cyclic stability. It delivers reversible capacities of 177 and 97 mAh g−1 at 0.05 and 5 C within 2.0–4.4 V, respectively. Galvanostatic intermittent titration technique verifies faster kinetics of Na+ diffusion in NMTC-F0.08. And in-situ XRD investigation reveals the phase evolution of NMTC-F0.08, indicating enhanced structural stability results from F-substitution. This study may shed light on the development of high performance cathode materials for sodium-ion storage at high voltage.

The spin-forbidden nature of triplet exciton transitions is a limitation for achieving a carbon dots-based material with room-temperature phosphorescence (RTP). Here, fluorine-nitrogen co-doped carbon dots (FNCDs), prepared using the solvothermal method and further gas-phase fluorination from fructose and diethylenetriamine (DETA), were found to exhibit RTP lifetime and quantum yield of 1.14 s and 8.3%. By comparing the structure and performance of the nitrogen-doped carbon dots (NCDs) and FNCDs, it was found that the RTP of FNCDs originates from the π→π∗ and n→π∗ electron transitions C–N/C N, which can be attributed to the small energy gap between the singlet and triplet states. We further explored the mechanism of RTP by analyzing the hydrogen bonding between carbon dots and polyvinyl alcohol matrix. The semi-ionic C–F bonds also enhance intramolecular and intermolecular hydrogen bonding and reduce the quenching of RTP without the oxygen barrier. Furthermore, we applied the prepared aqueous FNCDs as an advanced security ink for information printing and anti-counterfeiting.

Fluoropolymers get increasing attention in energetic materials application due to the high fluorine content. To explore the effect of poly(vinylidene fluoride -co- hexafluoropropylene) (P(VDF-HFP)) on Al/MnO2 nanothermite, the samples with different contents are prepared and characterized by SEM, TG-DSC, XRD, and their ignition and combustion behavior are tested and recorded. The results show that P(VDF-HFP) as an energetic binder can combine the nanothermite components together, even exist in the gaps. The integrity of energetic materials has been improved. Thermal analysis shows that the addition of P(VDF-HFP) greatly changes the thermal reaction processes, and the exothermic peaks appear early, but the utilization of fuel and oxidizer is not efficient from the XRD results. Furthermore, the appropriate addition of P(VDF-HFP) can directly reduce the ignition energy threshold and increase the combustion time, which is necessary for the potential ignition charge application. The possible reasons for above phenomena are discussed and analyzed. This research provides a reference for improvement of thermite-based ignition charge formulation.

Transition metal electrocatalysts with high activity and long durability are desired for methanol oxidation reaction (MOR). Here, the surface fluorinated nickel-graphene nanocomposites (F–Ni–G) are synthesized via the reduction of Si–H bonds produced by silicon and ammonium fluoride in hydrothermal condition. During this process, ionic nickel-F bonds and semi-ionic C–F bonds are introduced to the catalysts as confirmed by X-ray photoelectron spectroscopy. When F–Ni–G nanocomposites are employed as MOR catalysts, the surface fluorination is contributed to the formation of nickelic, which can increase the activity and kinetics for MOR. The onset oxidation potential of F–Ni–G-2 for methanol oxidation is 53 mV lower than that of the Ni/G catalyst without fluorine. The mass activity of F–Ni–G-2 (2493.3 A g−1) is 3.90 folds than that of Ni/G (638.5 A g−1). In addition, the density functional theory calculation indicates that the modified fluorine in graphene results in the decreased reaction energy barrier from ∗CO to ∗COOH step in MOR. The strong electronegativity of F atom makes intermediates easier to attract OH− groups and repel protons, which is conductive to decrease the reaction energy barrier for MOR. Such a facile method for the fabrication of the surface fluorinated catalytic system may be extended to the preparation of other transition metal electrocatalysts.

Copolymers of poly(pentyl acrylate-co-methyl methacrylate) [P(PA-co-MMA)] were manufactured by using carbon dioxide with dispersion polymerization. The thermophysical characteristics of P(PA-co-MMA) were researched with three kinds ratios (1:20, 1:25, and 1:30) of PA vs. MMA and AIBN concentrations of (1.0, 2.0, and 4.0) wt%. Experimental product source at pressures of p ≤ 206 MPa and temperature of T ≤ 434 K was investigated for two- and three-components solution of P(PA-co-MMA) under compressed CO2, CHClF2, CHF3 and CH2F2. Experiments are carried out to get phase separation measurement for the two-component solution of P(PA-co-MMA) [1:25 mole ratio, AIBN of (1.0, 2.0 and 4.0 wt%] + compressed fluorine solvents (CHF3, CHClF2and CH2F2) solutions at a pressure of p

Objective The aim of the present study was to determine the chemical species formed inside glass-ionomer cements after fluoride uptake and to investigate the depth of penetration of fluoride ions within the cement matrix. Methods An experimental fluoride-free glass with composition 2SiO2–AlO3–CaO was produced. The glass powder was mixed with aqueous poly(acrylic acid) (PAA), and allowed to set. The resulting specimens were stored in 20 ml KF solution with 1000 ppm fluorine for 24 h and then placed into the same amount of water as for 24 h. A fluoride selective electrode was used to give the F concentration of the respective solutions. 19F MAS-NMR spectra were recorded on powdered cement specimens using a Bruker AVANCE-NEO 600 spectrometer. In addition, SEM observation and EDX chemical analysis were conducted on the cross-section of a carefully fractured specimen. Results Fluoride was shown to be mainly present in the surface layers of the specimen after placement in the KF solution, and only a small fraction was re-released into water. 19F NMR spectroscopy showed that AlF complexes were formed within the cement. Significance The fluoride taken up by a free-fluoride glass ionomer cement mostly occupies surface layers and is retained because it bonds to aluminum within the matrix. This finding explains why the majority of fluoride taken up by conventional glass ionomer cements is retained.

Although graphene film has received considerable scientific and industrial interest, the high electrical conductivity strongly limits its corrosion protection over a long-term scale. Here we develop an effective strategy to achieve the long-term corrosion protection performance of graphene film by fluorinated treatment. The success of fluorination strategy is evident in electrochemical impedance spectroscopy, local impedance module, and corresponding corrosion morphologies and structures. Even after 14 days’ immersion in 3.5 wt% NaCl solution, the low frequency impedance modulus of fluorinated graphene film with fluorinated treatment at 100 °C is an order of magnitude higher as compared with pristine one. The corrosion resistance over a large scale also persists in air environment. We propose that the fluorine atoms bond with carbon element on the edge of vacancy defects, inhibiting the corrosion-related molecules passing through the film via intrinsic defects, this is supported by the density functional theory calculations (DFT). In brief, through effective preparation, analysis of corrosion resistant performance, and theoretical calculation, the fluorinated graphene film with long-term anti-corrosion capability is highly expected to open a new platform for practical applications.

Fundamental cross section measurements are essential for particle-induced gamma emission (PIGE) analysis. 19F( p , α γ 2 - 0 )16O can be utilized in PIGE analysis; however, differential cross section measurements for this reaction do not exist due to the difficulty in deconvolving overlapping peaks in the gamma spectrum. Although gamma yield measurements for this reaction exist (Dababneh et al., 1993), these can only be used for relative measurements. This work presents the 6.13 MeV gamma production differential cross sections for the 19F( p , α γ 2 - 0 )16O reaction in the incident proton kinetic energy range of 837 to 1517 keV. The yield of the 6.13 MeV gamma was obtained by subtracting the contribution of the 7.12 MeV double escape peak using the experimentally-determined ratio of the escape peaks. The corrected yields were converted to differential cross sections, which are presented here for the first time, as a contribution to the current knowledge and utilization of PIGE techniques.

Ammonium salts (NH4Cl and CO(NH2)2) were used as grinding aids for crushing waste polytetrafluoroethylene (PTFE) to produce ultrafine PTFE powder (d50 = 30 μm) for the first time. PTFE was first dry-milled with the ammonium salts, after which the ground sample was washed with water to remove the soluble salts. X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), thermogravimetric differential scanning calorimetry (TG-DSC), and scanning electron microscopy (SEM) techniques were used to evaluate the mechanism of PTFE fractionation. A small part of the C–F2 bonds was transformed to -CH2- during ball-milling. Without the covering of the fluorine atoms, the PTFE molecular chain fractured at the position of the -CH2- group, thereby reducing the diameter of PTFE. The proposed ball-milling process is facile and effective for recycling waste PTFE and producing ultrafine PTFE powder with high economic value.

The power conversion efficiencies (PCEs) of organic solar cells (OSCs) have reached 18% recently, which have already met the demand of practical application. However, these outstanding results were generally achieved with donor-acceptor (D-A) type copolymer donors, which can hardly fulfill the low-cost large-scale production due to their complicated synthesis processes. Therefore, developing polymer donors with simple chemical structures is urgent for realizing low-cost OSCs. Polythiophene (PT) derivatives are currently regarded as promising candidates for such kind of donor materials, which has been illustrated in many works. In this work, two new alkylthio substituted PT derivatives, P301 and P302, were synthesized and tested as donors in the OSCs using Y5 as the acceptor. In comparison, the introduction of fluorine atoms on the backbone of P302 can not only downshift the energy levels, but also greatly improve the phase separation morphologies of the active layers, which is ascribed to the enhanced aggregation effect and the reduced miscibility with the non-fullerene acceptor. As a result, the P302:Y5-based OSC exhibits a significantly improved PCE of 9.65% than that of P301:Y5-based one, indicating the important role of fluorination in the construction of efficient PT derivative donors.

Fluorine substitution in molecular design has become an effective strategy for improving the overall performance of organic photovoltaics. In this study, three low-cost small molecules of spiro-linked hole transporting materials (SFX-o-2F, SFX-m-2F, and SFX-p-2F) endowed with two-armed triphenylamine moieties were synthesized via tuning of the fluorine substitution position, and they were employed for use in highly efficient perovskite solar cells (PSCs). Despite the fluorine substitution position playing a negligible role in the optical and electrochemical properties of the resulting small molecules, the photovoltaic performance thereof was observed to vary significantly. The planar n-i-p PSCs based on SFX-m-2F demonstrated superior performance (18.86%) when compared to that of the corresponding SFX-o-2F (9.7%) and SFX-p-2F (16.33%) under 100 mW cm-2 AM1.5G solar illumination, which is competitive with the performance of the benchmark spiro-OMeTAD-based device (18.98%). Moreover, the SFX-m-2F-based PSCs were observed to be more stable than the spiro-OMeTAD-based devices under ambient conditions. The improved performance of SFX-m-2F is primarily associated with improved morphology, more efficient hole transport, and extraction characteristics at the perovskite/HTM interface. This work demonstrated the application of fluorination engineering to the tuning of material film morphology and charge transfer properties, showing the promising potential of fluorinated SM-HTMs for the construction of low-cost, high-efficiency PSCs.

Nine fluorine targets of various types were developed for the 19F( p , α )16O experiment to be performed at the Jinping Underground Nuclear Astrophysics Experiment (JUNA), China. Two targets were produced by evaporating CaF2 on Ta backings: one was produced by sputtering MgF2 on the Cr+Fe backings, and six were produced by implanting 20–80 keV 19F ions into pure Fe and Cu backings. Thin Cr protective layers were covered over these targets. We assessed each target’s stability by monitoring the γ -ray yields of the 19F( p , α γ )16O reaction over the well-known 340 keV resonance. Our results indicate that the traditional evaporated and sputtered targets exhibit 0.6%–6% deterioration (or 19F material loss) per Coulomb, while the implanted targets exhibit relatively small deterioration due to the proton beam bombardment. For the optimum target #8, the 19F target material loss is only approximately 0.05% per Coulomb proton beam bombardment, and such target is much more stable than the traditional targets. The fluorine depth distribution of the implanted target #8 was precisely analyzed by the atom probe tomography (APT) technique. The obtained depth distribution can well reproduce the experimental γ -ray yield curve. Furthermore, as test experiment, the 19F( p , α γ )16O cross section was measured with the implanted target #8 in a center-of-mass energy region of E c.m. = 174–358 keV, which is consistent with the previous results. In conclusion, traditional fluorine targets produced with the evaporation and sputtering techniques are not suitable for the high-current experiment even with a protective layer. For the upcoming high-current JUNA experiment, this work offers an optimum target scheme: first, implanting 19F ions into the pure Fe backings with an implantation energy of 40 keV, and then sputtering a 50 nm thick Cr layer to further prevent the fluorine material loss.

Fluorapatite exhibits improved bone-bonding and chemical durability under neutral and acidic conditions compared with hydroxyapatite. Typically, an aqueous fluoride solution is used for F− incorporation into the hydroxyapatite. Use of an ionic liquid as F− source provides highly-concentrated ionic environment and can lead to more effective fluorination. In this study, two ionic liquids were added during the synthesis of hydroxyapatite under various conditions, and the differences in the crystalline structure and chemical durability of the resulting fluorapatites were investigated. 1-ethyl-3-methylimidazolium tetrafluoroborate was quite effective for F− incorporation, but not 1-ethyl-3-methylimidazolium hexafluorophosphate. When the temperature was increased to 80 °C, not only the hydroxyapatite or fluorapatite but also CaF2 was generated as a by-product. When the initial pH was decreased to 7, the formed product fully converted to CaF2. The solubility of the product tended to be suppressed in acidic conditions with increase in amount of fluorine substituted in the crystal lattice.

In this communication, we propose a novel method to electrochemically modify hydrogen-terminated diamond surface in MISFETs with LiF dielectric at room temperature. The chemical reaction is 2F- + C–H+2h+→C–F + HF. According to measurement results of X-ray photoelectron spectroscopy on diamond, C–F bonds were produced after electrochemistry modification. A model was proposed to explain the electrochemistry modification on MISFETs. In this model, the theoretical electrolysis voltage of F− was calculated to be −3.8V, which was consistent with the experimental value of -5V.

For improving the performance of hole transport materials (HTM) in the utilization of perovskite solar cells (PSCs), the structure-performance relationships of HTM must be revealed. In this work, six HTMs with same 6,12-dihydroindeno[1,2-b]fluorine (IDF) core are studied theoretically to reveal the influences of difference type and number of electron-donating group on the performances of HTMs. Results showed that star-shaped HTMs should have larger open-circuit voltage (VOC), better optical performances than linear-shaped HTMs. Meanwhile, using one thiophene substitute a benzene on the electron-donating group Diphenylamine derivative (DPA) is expected to enhance the VOC of PSCs and Stokes shift of HTM. Both the type and number of electron-donating group have slight effects on hole injection, electron-blocking and molecular stability of HTM. Most importantly, both thiophene substituted DPA (T-DPA) group and linear structure make the molecular stacking more compact, leading the transfer integral in the main hopping pathway improved evidently. Thus, the hole mobilities of HTMs are increased obviously. Furthermore, results also show that two thiophene substituted DPA could lead the molecular stacking more compact, which could be favorable for improving the hole mobility of HTMs. Our investigation proves and provides two efficient strategies to modulate the performances of HTMs and reveals the structure-performance relationships of HTMs.

We functionalized primary amine groups (NH2-) to single-walled carbon nanotubes (SWCNTs) by reacting fluorinated SWCNTs with ammonia gas at a low temperature and characterized NH2-functionalized SWCNTs which were prepared by defluorinating the remaining fluorine groups via a hydrazine treatment. It is evident from the results of the Kaiser test and X-ray photoelectron spectroscopy that a few primary amine groups were functionalized onto the nanotubes. The average number of NH2 groups in the NH2-functionalized SWCNTs was 21.5 μmol/g. One primary amine group was functionalized per about 500 carbon atoms on the outermost surface of the bundled nanotube frame. The zeta potential of the SWCNTs was found to be +14 mV (pH = 3.0) and the specific capacitance of the NH2-SWCNTs was approximately 1.7 times higher than the hc-SWCNTs at a scan rate of 10 mV/s, which indicated the functionalization effect of the primary amine groups.

The bastnaesite used in hydrometallurgy usually contains 7%–11% fluorine, and the conversion of fluorine into high-value products is the key to achieving green production of rare earths and improving the comprehensive utilization of bastnaesite. In order to recover fluorine from bastnaesite in the form of KBF4, the mechanism of F− conversion to BF 4 − in sulphuric acid leaching solution of roasted bastnaesite was studied by using Eh–pH diagram and simulation experiment. It shows that the formation of BF 4 − is affected by pH in the absence of rare earths. BF 4 − is hydrolyzed to BF3OH− and F− when the pH is greater than 3.9, and part of F− exists as HF 2 − when pH is lower than 2. In the presence of La3+, the formation of BF 4 − is mainly affected by LaF3 when pH is greater than 0, and in the case that the pH is lower than 2, it is mainly affected by HF 2 − . When Ce4+ is present in solution, CeF 2 2 + can exist stably in sulphuric acid solution. Bringing down the pH can reduce the stability of CeF 2 2 + and increase the BF 4 − conversion rate. Based on these results, KBF4 was prepared in the alkaline solution of bastnaesite, and the conversion of BF 4 − is 84.31%. This provides a theoretical basis for the recovery of fluorine from bastnaesite in the form of KBF4.

This work dealt with the substituent effect on the chemical reactivity behavior of the title compound. First, the geometry optimizations and structure verifications of all substituted compounds were done with the B3LYP/6-311G(d,p) level, in both the gas and chloroform. Then, the spectroscopic properties (FT-IR and NMR) of all compounds were evaluated and compared with the corresponding reported data. Furthermore, the NLO (non-linear optic) work of the compounds was performed to look for the availability for using in optoelectronic devices. Last, the FMO analyses were conducted to compare the possible reactivity tendency all indole derivatives with the main structure. NLO results revealed that all cis- and trans substituted compounds were greater “β” value than that of the urea, and R2B compound could be a good choice for using in optoelectronics because β (9.09 × 10−30 esu) of R2B was greater 15 times than that of the urea. In both environments, the fluorine substitution made the R compound more sensible to outer molecular system because the energy gap value of R2A (4.6107 eV) and R1A (4.5519 eV) in gas were calculated greater than that of the other compounds.

This paper presents some experimental results about the 7Li, 11B and 19F (p, α) nuclear reactions developed using proton beams at energy below 3 MeV in order to be applied to protontherapy. The energy released by proton beams during radiotherapy acts mainly at the end of the proton path in the biological medium, where it increases at high density inside the tumor. At this depth, it is possible to inject in the tumor compounds containing Li, B and F to generate energetic alpha particles from nuclear reactions. At the proton Bragg peak position it is possible to produce 1–8 MeV alpha particles, which enhance the energy density deposited in the tumor increasing the probability to damage the cells. Thanks to the higher relative biological efficiency of the alpha particles with respect to protons, it is expected that the alpha synergic particles defeat the tumor at lower doses.

Tantalic oxide (Ta2O5), as an excellent transition metal oxide photocatalyst, has been extensively studied on fluorination or self-doped for hydrogen production, while there is little research to combine the two modifications. In this work, surface fluorination self-doped Ta2O5 nanoshuttles (FTNSs) photocatalyst is synthesized successfully by a modified one-step hydrothermal method. The test results show the presence of surface fluorine ions, Ta4+ and oxygen vacancies in the sample. The FTNSs prepared by hydrothermal method under 180 °C for 24 h exhibits the highest hydrogen evolution rate (HER). The HER is 179.2 and 19.78 μmol h−1 g−1 in the absence of any co-catalyst under full-spectrum and simulated solar light, respectively, which is higher than that of the Ta2O5 nanoshuttles without fluoride and the commercial Ta2O5. The higher HER can attribute to the existence of F, Ta4+ and oxygen vacancies, which enhance the photogenerated carrier mobility and reduce the recombination.

Cr doped Ruddlesden-Popper compound Sr2TiO4 has been successfully modified by fluorine to form a new compound Sr2Ti0.95Cr0.05O3F2. Structure analysis suggests two types of fluorine in the structure of this new compound, i.e. intralayer and interlayer F, which induce strong built-in electric field within this layered compound. The electric field stems from uneven distribution of F atoms on the two sides of perovskite layers therefore leads to charge disproportionation. DFT calculations suggest that this unique structural feature is highly beneficial for charge dissociations as it breaks the coplanar settlement of conduction band minimum and valence band maximum whilst maintains the 2D charge transportation properties. This is clearly demonstrated by the superior photocatalytic activities of Sr2Ti0.95Cr0.05O3F2 for hydrogen production from water. Apparent quantum efficiency (AQE) as high as 1.16% at 420 ± 20 nm has been achieved which stands as the highest AQE reported on Sr2TiO4 to date. Photoelectrochemical (PEC) analysis confirms improved charge separation conditions and prolonged charge lifetime.

β-cyclodextrins (β-CDs) are able to trap and hydrolyze certain nerve agents such as sarin. Herein, we studied the host-guest interactions of sarin with β-CD by performing quantum mechanical (QM) calculations and molecular dynamics (MD) simulations. The calculated results indicated that the stable inclusion complex can be formed in both vacuum and water. Also, dynamic and structural parameters revealed that the intramolecular hydrogen bonds and van der Waals interactions effectively help to maintain the stability of the sarin structure within the β-CD cavity. More importantly, it was shown that how the interactions of host’ components with phosphorus and fluorine of sarin can help to hydrolysis and thus detoxify sarin.

One of the most important factors to commercialized yttria-stabilized zirconia (YSZ)-based solid oxide fuel cell (SOFC) is a highly active mixed-conducting cathode at reduced temperatures. Herein, we propose a new strategy of fluorine anion (F−) doping to enhance electrochemical performance of the H+/O2−/e triple-conducting BaCo0.4Fe0.4Zr0.1Y0.1O3-δ (BCFZY) perovskite cathode for YSZ-based SOFCs. The F−-doped BCFZY as BaCo0.4Fe0.4Zr0.1Y0.1O2.95-δF0.05 (BCFZYF) retained the cubic structure with better symmetry. The doping of minor fluorine in oxygen-site was found to increase the oxygen exchange capability and thus oxygen reduction reaction (ORR) catalytical activity, as reflected by lower area specific resistance (ASR) of cathode on symmetrical cells. Maximum power density of 786 mWcm−2 was achieved at 800 °C for anode-supported single cell with BCFZYF cathode, being 1.7 times higher than that with BCFZY cathode. Furthermore, the single cell with BCFZYF cathode demonstrated excellent stability without any degradation of current density over 200 h at 700 °C. The present work clarifies that the fluorine doping strategy is highly effective to promote the ORR activity of the triple-conducting BCFZY cathode for state-of-the-art oxygen-conducting SOFC.

Owing to the superiority of high-power density and excellent cycling stability, supercapacitors (SCs) have been expected to substitute for secondary batteries as the desired orientation selected for energy storage devices. The incorporation of various heteroatoms into carbon-based materials via surface functionalization or doping technique has been considered as a significant way to ameliorate its properties for SCs application. In this review, a wide variety of fluorine-doped/fluorinated carbon-based materials are put together to overview the development path, preparation route and areas of application in detail. We critically review the optimization effect in electrochemical performance induced by the participation of fluorine element. Moreover, compared with large-scale energy storage devices, miniaturization, flexibility and planarization are an emerging development tendency of SCs. Fluorine-doped/fluorinated carbon-based materials hold great promise in the future.

Fluorinated porous carbon nanoweb layers (FPCNWLs) are simply fabricated by spin coating of adjusting polymer mixing ratio, sequential thermal treatments, and vacuum plasma treatment to enhance the specific surface area and to dope the fluorine into the carbon lattice. The different surface tension, polarity, and molecular weight of PAN and PS causes immiscible solution, therefore, the various size of pores on the carbon structure are constructed during the stepwise thermal treatment. Moreover, the F doping ratio is easily controlled with different plasma treating time. The fluorination causes both p-type doping and affinity toward ammonia gas. The fabricated FPCNWLs-based ammonia gas sensor devices demonstrate outstanding NH3 gas sensing performances that minimum detection level (MDL) of FPCNWLs-based ammonia gas sensor is 9 ppb using FPCNWL20 and the sensors display linear range from 9 ppb to 90 ppm. In conclusion, the FPCNWL20-based ammonia gas sensor demonstrates rapid response and recovery time, excellent cyclic stability, reusability, durability, and selectivity.