Synthesis, surface properties and cytotoxicity evaluation of nonionic urethane fluorinated surfactants with double short fluoroalkyl chains

Synthesis, Surface Activity, and Foamability of Two Short-Chain Fluorinated Sulfonate Surfactants with Ether Bonds

Fluorinated surfactants are widely used in many fields because of their excellent surface active properties, but their high stability has caused many environmental problems. With the ban and restriction of classical long-chain fluorinated surfactants such as perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) worldwide, the development and replacement of their alternatives is now a major challenge. How to reduce environmental persistence, bioaccumulation, and biotoxicity while maintaining high surface activity has become an important issue in the development of fluorinated surfactants. Using short-chain fluorinated surfactants is one of the important solutions to resolve the pollution of organic fluorinated compounds. In this article, we synthesized two short-chain fluorinated surfactants with ether bonds. One of them 6:2 FTESNa (2) used the perfluoroalkyl chain (n-C6F13-) and the other C72 FEESNa (4) used the fluoroether segment with six fluorinated carbons and two oxygens (CF3OCF(CF3)CF2OCF(CF3)). The surface activity, foam performance, and wettability of the two molecules were measured. The surface tensions at critical micelle concentration (γcmc) and the critical micelle concentration (cmc) of 2 and 4 were 17.6 mN/m (2.2 g/L) and 20.2 mN/m (4.6 g/L), respectively. Both of them were significantly superior to the surface activity of 6:2 FTSNa (7) which is one of the current alternatives for PFOS. Additionally, the foamability and foam stability of both 2 and 4 were better than that of 7. In the aspect of wettability on PTFE, that of 4 was greater than those of 2 and 7. In summary, this work provided a new choice for alternatives of PFOS and PFOA.

Perspectives on Corrosion Inhibition Features of Novel Synthesized Gemini-Fluorinated Cationic Surfactants Bearing Varied Spacers for Acid Pickling of X60-Steel: Practical, and In Silico Calculations

Through our present study, three novel Gemini-fluorinated cationic surfactants bearing different spacers (FSG6-2, FSG6-4, and FSG6-6) were synthesized, and their structures were explained via different spectroscopic instruments such as ¹H, ¹³C, and ¹⁹F NMR spectra. The surface activity of the as-prepared surfactants was examined. The inhibiting influence of FSG6 molecules on the X60 steel corrosion in the pickling solution (HCl) was examined by diverse methods comprising electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), and X-ray photoelectron spectroscopy (XPS) experimentations, and computational calculations. The inhibition effectiveness of FSG6 surfactants followed the order of 93.37% (FSG6-2) < 96.74% (FSG6-4) < 98.37% (FSG6-6) at 2.0 × 10^-4 M. The FSG6 surfactants function as mixed-type inhibitors, according to PDP investigations. The H₂O molecules that adsorbed on the steel interface were substituted with surfactant molecules, and the surfactant's inhibitory activity is likely caused by the improvement in an adsorptive layer on the steel substrate, as specified by the EIS results. The Langmuir isotherm describes the absorption of FSG6 molecules on the metal surface. The XPS investigations validate the steel interface's extremely protective nature. The mechanism of interaction between FSG6 molecules with an X60-steel employing the DFT calculations and MC simulations methods was also examined and discussed.

Promoting Efficacy and Environmental Safety of Pesticide Synergists via Non-Ionic Gemini Surfactants with Short Fluorocarbon Chains

Improving the utilization rate of pesticides is key to achieve a reduction and synergism, and adding appropriate surfactant to pesticide preparation is an effective way to improve pesticide utilization. Fluorinated surfactants have excellent surface activity, thermal and chemical stability, but long-chain linear perfluoroalkyl derivatives are highly toxic, obvious persistence and high bioaccumulation in the environment. Therefore, new strategies for designing fluorinated surfactants which combine excellent surface activity and environmental safety would be useful. In this study, four non-ionic gemini surfactants with short fluorocarbon chains were synthesized. The surface activities of the resulting surfactants were assessed on the basis of equilibrium surface tension, dynamic surface tension, and contact angle. Compared with their monomeric counterparts, the gemini surfactants had markedly lower critical micelle concentrations and higher diffusivities, as well as better wetting abilities. We selected a single-chain surfactant and a gemini surfactant with good surface activities as synergists for the glyphosate water agent. Both surfactants clearly improved the efficacy of the herbicide, but the gemini surfactant had a significantly greater effect than the single-chain surfactant. An acute toxicity test indicated that the gemini surfactant showed slight toxicity to rats.

Fluorinated surfactants: A review on recent progress on synthesis and oilfield applications

The selection of appropriate chemicals and the synthetic method plays an important role in oilfield application. The objectives of this study are to describe the various synthetic route for the preparation of fluorinated surfactants and highlight their oilfield applications. Fluorinated surfactants are the type of surfactants where the hydrophobic tail is either partially fluorinated or replaced totally with fluorine molecules. Fluorinated surfactants have distinct properties compared to corresponding hydrocarbon surfactants such as lower surface tension, better efficiency in lowering the interfacial tension, both oleophobic and hydrophobic nature, high thermal stability, and better chemical tolerance. These properties make them a material of choice for several applications which include but are not limited to fire-fighting, household items, foaming, coating, and paints. Despite these attractive properties, environmental concerns associated with fluorinated surfactants is a major hurdle in extending the application of such surfactants. This review discusses the various synthetic routes for the synthesis of different classes of surfactants such as cationic, anionic, non-ionic, and zwitterionic surfactants. The fundamental surface/interface properties of the synthesized surfactants are also highlighted. In addition, the review highlights the application of fluorinated surfactants in the oil & gas industry.

Strong synergistic effect of cationic hydrocarbon surfactant and novel nonionic tri-block short-chain fluorocarbon surfactant mixtures on surface activity, wettability and solubilization

Abstract

Mixing hydrocarbon surfactants with fluorocarbon surfactants is still an important strategy to improve the economic benefits and performances of fluorocarbon surfactants and expand their range of application. Herein, we prepared a novel kind of hydrocarbon-fluorocarbon surfactant mixtures via mixing a cationic surfactant, cetyltrimethylammonium bromide (CTAB), with a tri-block nonionic short-chain fluorocarbon surfactant (F9EG13F9) in aqueous solution. The results showed that adding a small CTAB amount to F9EG13F9 (the molar fraction of CTAB in the mixture (x1) was 0.2) could greatly reduce its critical micelle concentrations (cmc) from 0.408 mmol/L to 0.191 mmol/L. At this x1, the contact angle of the mixture was the minimum (57.7 °) at 100 s on polytetrafluoroethylene film, which was even lower than that of F9EG13F9. Besides, CTAB/F9EG13F9 mixtures possessed better colloidal stability and solubilization ability toward hydrophobic dye (Sudan І) than F9EG13F9. The outstanding performances of binary surfactant mixtures benefited from the non-ideal mixing and strong synergistic effect evidence that CTAB/F9EG13F9 surfactant mixtures could be used in practical applications instead of individual F9EG13F9, thereby reducing the used cost of F9EG13F9.

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Synthesis and application of non-bioaccumulable fluorinated surfactants: a review

Abstract

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

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