Hyperbranched Polymeric Fluorosurfactants:Synthesis,Surface Activity and Their Application in Firefighting Foams

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

Solvation Engineering via Fluorosurfactant Additive Toward Boosted Lithium-Ion Thermoelectrochemical Cells

Lithium-ion thermoelectrochemical cell(LTEC), featuring simultaneous energy conversion and storage, has emerged as promising candidate for low-grade heat harvesting. However, relatively poor thermosensitivity and heat-to-current behavior limit the application of LTECs using LiPF_6 electrolyte. Introducing additives into bulk electrolyte is a reasonable strategy to solve such problem by modifying the solvation structure of electrolyte ions. In this work, we develop a dual-salt electrolyte with fluorosurfactant(FS) additive to achieve high thermopower and durability of LTECs during the conversion of low-grade heat into electricity. The addition of FS induces a unique Li~+ solvation with the aggregated double anions through a crowded electrolyte environment,resulting in an enhanced mobility kinetics of Li~+ as well as boosted thermoelectrochemical performances. By coupling optimized electrolyte with graphite electrode, a high thermopower of 13.8 mV K^(-1) and a normalized output power density of 3.99 mW m^(–2) K^(–2) as well as an outstanding output energy density of 607.96 J m^(-2) can be obtained.These results demonstrate that the optimization of electrolyte by regulating solvation structure will inject new vitality into the construction of thermoelectrochemical devices with attractive properties.

Functional Surfactants for Molecular Fishing,Capsule Creation,and Single-Cell Gene Expression

Creating a single surfactant that is open to manipulation,while maintaining its surface activity,robustness,and compatibility,to expand the landscape of surfactant-dependent assays is extremely challenging.We report an oxidation-responsive precursor with thioethers and multiple 1,2-diols for creating a variety of functional surfactants from one parent surfactant.Using these multifunctional surfactants,we stabilize microfluidics-generated aqueous droplets.The droplets encapsulate different components and immerse in a bioinert oil with distinct interfaces where an azide-bearing surfactant allow fishing of biomolecules from the droplets,aldehyde-bearing surfactant allow fabrication of microcapsules,and hydroxyl-bearing surfactants,with/without oxidized thioethers,allow monitoring of single-cell gene expression.Creating multifunctional surfactants poses opportunities for broad applications,including adsorption,bioanalytics,catalysis,formulations,coatings,and programmable subset of emulsions.

Detection of captopril based on its enhanced resonance light scattering signals of fluorosurfactant-capped gold nanoparticles

In this study,based on its enhancement effect on resonance light scattering (RLS) of fluorosurfactant (FSN)-capped gold nanoparticles (GNPs),we reported a simple approach for the rapid sensing of captopril. Under optimum conditions,the lowest detectable concentration of captopril through this approach (S/N=3) was 0.01μg/mL. The calibration curve was linear over the range of 0.08-4.0μg/mL for the detection of captopril. The recoveries of captopril were found to fall in the range between 99% and 100%. We have validated the applicability of our method through the analyses of captopril in pharmaceutical formulations. Good agreements were obtained for the determination of captopril between the present approach and official method.