Anionic Sulfonate Groups Research Articles

Proton conducting electrolytes composed of chondroitin sulfate polysaccharide and citric acid

Novel electrolytes composed of chondroitin sulfate A (CSA) and citric acid (CA) have been prepared using a clean, safe, and fast route. These electrolytes exhibit different physical-chemical properties, depending on the amount of CA. For X > 82.3%, where X is the mass ratio, in %, of CA/(CA + CSA), whitish polycrystalline powders result. Lower amounts of CA leads to the production of translucent, amorphous films, sticky for X = 75.6 and 82.0, brittle for X < 43.6 and crack-free, self-standing for 43.6 < X < 75.6%. The results obtained provide evidence that, at low pH, strong hydrogen bonding interactions take place between the anionic sulfonic and carboxylic groups of CSA and CA. CA exerts a key role, acting as a cross-linker and proton source, while simultaneously influencing sample morphology. At room temperature the highest ionic conductivity is achieved at X = 60.8%. A significant enhancement of the ionic conductivity of this sample occurs with the increase of relative humidity (RH) (from 3.1 × 10−7 to 3.7 × 10−2 S cm−1 30% for RH = 30 and ~100%, respectively).

Mechanistic insights into selective adsorption and separation of multi-component anionic dyes using magnetic zeolite imidazolate framework-67 composites

The development of highly efficient magnetic adsorbents, especially those aimed at adsorption and separation of multi-component dyes, is one of the new challenges in the water treatment field. In this study, zeolite imidazolate frameworks-67 (ZIF-67) loaded on magnetic nanoparticles named MZIF-67 composites was synthesized and applied to adsorption and separation of anionic dyes mixture. Direct blue 86 (DB-86) and methyl orange (MO) were selected as model contaminants. The most intriguing feature is that MZIF-67 can successfully separate DB-86 from mixed dye molecules in aqueous solution with high effectivity and selectivity, even for DB-86 molecule with a large size. The satisfactory adsorption and separation properties (adsorption capacity, equilibrium time, adaptability to solution changes and rapid magnetic separation) indicated MZIF-67 as an efficient adsorbent. Furthermore, the MZIF-67 before and after adsorption was carefully characterized by X-ray photoelectron spectroscopy (XPS) spectra which proved the main mechanism of MZIF-67 adsorption toward anionic dyes: ZIF-67 surface provided large number of uncoordinated cobalt sites bonding with hydroxide derived from water (Co–OH) and subsequently formed complex with anionic dyes under hydrogen bonding, accompanied by the electrostatic interaction between positively charged ZIF-67 and the anionic sulfonate group. This work is expected to provide insight mechanisms of MZIF-67 adsorption toward anionic dyes and offer promising magnetic ZIFs for multi-component system separation.

Amphoteric Membranes Based on Sulfonated Polyether Ether Ketone and Imidazolium‐Functionalized Polyphenylene Oxide for Vanadium Redox Flow Battery Applications

AbstractAmphoteric membranes were obtained from imidazolium‐functionalized polyphenylene oxide (ImPPO) and sulfonated poly(ether ether ketone) (SPEEK) for an all‐vanadium redox flow battery (VRFB) application. The SPEEK/ImPPO amphoteric membranes showed a considerably lower swelling degree and water uptake compared to those of pure SPEEK membranes, owing to the formation of ionic bonds between the cationic imidazolium groups of ImPPO and the anionic sulfonate groups of SPEEK. The cationic imidazolium groups of the ImPPO exhibited a Donnan exclusion effect on vanadium ions; therefore, the amphoteric membranes showed a much lower vanadium permeability than the pure SPEEK membrane. In addition, the vanadium permeability of the amphoteric membranes deceased with an increase in the ImPPO content. SPEEK‐ImPPO20 with 20 wt% ImPPO showed a vanadium permeability of 0.43×10−9 cm2 s−1 at room temperature, which is 17 times lower than that of Nafion 212 (8×10−9 cm2 s−1). The VRFB assembled with SPEEK‐ImPPO20 showed a coulombic efficiency of 97.2 % and a voltage efficiency of 85.8 % at a current density of 60 mA cm−2, whereas the values for Nafion 212 were 92.4 % and 86.7 % under the same conditions. In addition, the VRFB assembled with SPEEK‐ImPPO20 exhibited much better capacity retention than that assembled with Nafion 212. These results indicate that the SPEEK‐ImPPO amphoteric membrane is a promising material for VRFB applications.

One-Step Synthesis and Functionalization of High-Salinity-Tolerant Magnetite Nanoparticles with Sulfonated Phenolic Resin.

Superparamagnetic nanoparticles are being actively developed for various applications in oil fields. A key requirement for such nanoparticles is the long-term stability of their dispersion under harsh subsurface conditions such as high salinity and high temperature. In this study, through functionalization of the surface of the magnetite nanoparticles with a sulfonated phenolic resin, stable dispersions of the nanoparticles in 5 wt % NaCl solution at neutral to basic pH were achieved. Sulfonated phenolic resin is aromatic in nature and can endure high temperatures; moreover, the strongly anionic sulfonate groups facilitate sufficient electrostatic repulsion between the particles even in a highly saline environment. Sulfonated phenolic resin was synthesized by heating a mixture of 4-hydroxybenzenesulfonic acid and formaldehyde at 1:1 molar ratio. Then, by synthesizing magnetite nanoparticles by a co-precipitation process in a solution of sulfonated phenolic resin, one-pot synthesis/surface functionalization was accomplished, which not only simplifies the manufacturing process but also can potentially lower the cost of production owing to the use of readily available phenolic resins. The reliability of the technique was confirmed by the detailed characterization of the nanoparticle through size distribution analysis, thermogravimetric analysis, ζ-potential measurements, transmission electron microscopy imaging, and energy-dispersive X-ray spectroscopy mapping. Further, Langevin curve was generated for evaluating the superparamagnetism of the nanoparticles.

Potentially self-dopable poly(3-hexylthiophene) block copolymers/carbon nanotube nanocomposites for enhanced processibility and electrical properties

Development of new hole-transport layer (HTL) materials for organic photovoltaic (OPV) applications is one crucial issue to mitigate such limitations of low power efficiency, processibility, and stability derived from poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) as a common HTL material. To this end, poly(3-hexylthiophene) (P3HT)-based diblock copolymers including the different ratios between polystyrene (PSty) or/and poly(neopentyl styrene sulfonate) (PNSS) as a second block segment were designed and then used for incorporating with single wall carbon nanotubes (SWCNTs) to form potentially self-dopable nanocomposites. The structure of fabricated P3HT-based diblock copolymer/SWCNT nanocomposites was examined by microscopic and spectroscopic characterizations, exhibiting a charge transfer behavior between P3HT and SWCNT, and growth of the P3HT crystalline phase along the SWCNT surface with a form of the conducting path. The acquired SWCNT nanocomposites exhibited good solubility and dispersion in various organic solvents including toluene, chlorobenzene, THF, chloroform, and DMF, which are good solvents for the PSty or/and PNSS neutral second block. The concept for the neutralized second block by protecting groups can prevent the poisoning ITO substrate by water contamination as shown in the conventional aqueous PEDOT-PSS solution. Notably, the PNSS constituent in the nanocomposite was merely acidified to give in-situ sulfonic acid groups in PSty by simple thermolysis process at 160 °C for 30 min after a solution process for fabrication of a thin film. The thermolysis step provided efficient doping of P3HT by PSS, in which the thiophene groups worked as Brønsted base are protonated by taking protons from sulfonic acid groups and then lead to a form of ionic bonds between cationic thiophene and anionic sulfonate groups. In addition, the formed ionic bonds in the nanocomposites led to an insoluble thin film, which has a good advantage for the further solvent process without substantial damages. The beneficial features of the conducting path along SWCNT and the efficient doping of P3HT by PSS in the acquired nanocomposites led to ca. 5-fold higher electrical conductivity (3.16 S cm−1) and similar work function (5.1 eV) in comparison to water contained commercial PEDOT:PSS (0.6 S cm−1 and 5.0 eV, respectively). As such, the rationally designed potentially self-dopable SWCNT nanocomposites can be one of the promising alternatives beyond the commercial PEDOT: PSS HTL material.

Development of Hierarchically Porous Ionomer Membranes for Versatile and Fast Metal Ion Conduction.

Innovative design concepts can play a key role in the realization of high-performance ionomer membranes that are capable of exclusive metal ion conduction and potentially applicable in electrochemical devices including sensors, fuel cells, and high-energy batteries. Herein, we report on the development of new ionomers, based on sulfonated poly(ether ether ketone) (SPEEK), engineered to conduct a variety of ions, namely, Li+, Na+, K+, Zn2+, and Mg2+, when soaked with nonaqueous solvents. Application of a facile phase-inversion method results in M-SPEEK (M = Li/Na/K/Zn/Mg) membranes with a hierarchical porous network, facilitating organic solvent infusion that is necessary to promote dissociation and rapid transport of cations between anionic sulfonate groups on the polymer chains. This strategy leads to membranes with alkali ion conductivities approaching 10–4 S cm–1 at room temperature, and near unity cation transference numbers (tM+ ≥ 0.9). Furthermore, an exceptionally high Zn-ion conductivity of 10–2 S cm–1 is obtained for the water-infused Zn-SPEEK membrane. In comparison, the dense membranes demonstrate 2–3 orders of magnitude lower conductivities because of insufficient solvent infusion. Preliminary electrochemical studies with solvent-infused ionomer membranes as the electrolyte look promising.

Ion Mobility Measurements of Multianionic Metalloporphyrin Dimers: Structural Changes Induced by Countercation Exchange.

We present gas-phase structures of dimers of MnIII and FeIII meso-tetra(4-sulfonatophenyl)porphyrin multianions with various amounts of sodium and hydrogen counterions. The structural assignments are achieved by combining mass spectrometry, ion mobility measurements, quantum chemical calculations, and trajectory method collision cross section calculations. For a common charge state, we observe significant topological variations in the dimer structures of [(MTPPS)2+nX](6-n)- (M=MnIII, FeIII; X=H, Na; n = 1-3) induced by replacing hydrogen counterions by sodium. For sodium, the dimer structures are much more compact, a finding that can be rationalized by the stronger interactions of the sodium cations with the anionic sulfonic acid groups of the porphyrins as compared to hydrogen. Graphical Abstract ᅟ.

Adsorption kinetics and equilibrium studies for removal of acid azo dyes by aniline formaldehyde condensate

Adsorption of two acid dyes named Acid orange 8 (AO8) and Acid violet 7 (AV7) by amine based polymer aniline formaldehyde condensate (AFC) was studied. Adsorption of both dyes was favored at acidic pH. Electrostatic attraction between protonated amine group (NH3+) of AFC and anionic sulfonate group (SO3−) of dye molecule along with hydrogen bond formation and interaction between aromatic group of dye and AFC were responsible mechanisms for dye uptake. Isotherm of AO8 was Type I and followed Langmuir isotherm model. AV7 isotherm on AFC was of Type III and followed Freundlich model. Kinetics study showed that external mass transfer was the rate limiting step followed by intraparticle diffusion. Maximum adsorption capacities of AO8 and AV7 were observed as 164 and 68 mg/g. AO8 dye being smaller in molecular size was adsorbed more due to higher diffusion rate and higher dye: AFC ratio, which enhanced the interaction between dye and polymer.

STRUCTURE-TRANSPORT RELATIONSHIP OF PERFLUOROSULFONIC-ACID MEMBRANES IN DIFFERENT CATIONIC FORMS

Perfluorosulfonic-acid (PFSA) ionomers are widely used as solid electrolytes and ion-exchange membranes in electrochemical devices, wherein their properties are impacted by the interactions among the anionic sulfonate groups, mobile counter-ions (cations), and hydration levels. Cation-form and humidity collectively affect the structure/transport-property relationship, yet their interplay is still not well known. In this paper, we report changes in water uptake and conductivity of cation-exchanged PFSA in both vapor and liquid water, which are then correlated with changes in mechanical properties and nanostructure (hydrophilic-domain spacing and phase-separation). It is found that the magnitude of changes depends significantly on the membrane water content, with master curves in terms of water volume fraction and water per charge realized. Moreover, membrane nanostructure and dynamical-mechanical behavior is examined to establish structure/transport and transport/stability relationships. It is found that with increasing cation size (radius) and valence, the storage modulus increases, while the water uptake and conductivity decrease. In addition, regardless of the cation type, a universal relationship is found between the conductivity and modulus, indicative of a transport/stability tradeoff. The extent to which the cations impact the transport properties depends on the water content: at low hydration levels the controlling factor is the cation (and its interaction with the sulfonate sites), at increasing hydration the dominant factor becomes water volume fraction, although it is also controlled by the cations. Similarly, the decrease in hydrophilic domain spacing of PFSA exchanged with larger cations scales with cation radius at low water contents, but with Lewis acid strength (LAS) at higher hydration levels. The findings reported here not only provide valuable insights into the interaction between sulfonate groups, cations, and water surrounding these ionic groups, but also for understanding cation contamination in fuel cells and redox flow batteries.

Molecular Dynamics Study of N-Dodecyl-N,N-Dimethyl-3-Ammonio-1-Propanesulfonate Mono-Layer Adsorbed at the Air/Water Interface

Molecular dynamics (MD) simulation has been carried out to investigate the properties of a mono-layer of N-dodecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (SB12-3) adsorbed at the air/water interface. The simulation results show that SB12-3 can form a closely packed mono-layer at the air/water interface, the anionic sulfonic groups of the hydrophilic head group have stronger interactions with the water molecules by comparison with the cationic quaternary nitrogen of the hydrophilic head group, and water molecules can gather more easily and aggregate around the sulfonic groups. With the addition of the Ca2+ ions, the number of hydrogen bonds between the SB12-3 surfactant molecules and water molecules remains almost unchanged, which may explain the salt resistance behavior for SB12-3 especially for di-valent ions. The hydrophobic tail in SB12-3 is more ordered in the beginning of the chain.

Sodium ion dynamics in a sulfonate based ionomer system studied by 23Na solid-state nuclear magnetic resonance and impedance spectroscopy

A poly(2-acrylamido-2-methyl-1-propane-sulphonate) (PAMPS) ionomer containing both sodium and quaternary ammonium cations functionalised with an ether group, has been characterised in terms of its thermal properties, ionic conductivity and sodium ion dynamics. The ether oxygen was incorporated to reduce the Na+ association with the anionic sulfonate groups tethered to the polymer backbone, thereby promoting ion dissociation and ultimately enhancing the ionic conductivity. This functionalised ammonium cation led to a significant reduction in the ionomer Tg compared to an analogue system without an ether group, resulting in an increase in ionic conductivity of approximately four orders of magnitude. The sodium ion dynamics were probed by 23Na solid-state NMR, which allowed the signals from the dissociated (mobile) and bound Na+ cations to be distinguished. This demonstrates the utility of 23Na solid-state NMR as a probe of sodium dynamics in ionomer systems.

A colourimetric sensor for the simultaneous determination of oxidative status and antioxidant activity on the same membrane: N,N-Dimethyl-p-phenylene diamine (DMPD) on Nafion

A colourimetric sensor capable of simultaneously measuring oxidative status (OS) in terms of the hazard produced by reactive oxygen species (ROS) and antioxidant activity (AOA) in regard to ROS-scavenging ability of antioxidant compounds was developed. The coloured cationic semi-quinone derivatives, caused by ROS oxidative degradation of N,N-dimethyl-p-phenylene diamine hydrochloride (DMPD) in pH 5.7 acetate-buffered medium, were formed in solution and immobilized on a perfluorosulfonate-based Nafion membrane. ROS, namely hydroxyl (OH) and superoxide (O2−) radicals, were produced by Fenton/UV and xanthine/xanthine oxidase methods, respectively. The pink-coloured, (+)-charged chromophore (referred to as DMPD-quinone or DMPDQ), resulting from the reaction between DMPD and ROS, could be completely retained on the solid membrane sensor by electrostatic interaction with the anionic sulfonate groups of Nafion. After equilibration, the Nafion membrane surface was homogeneously coloured enabling an absorbance measurement at 514nm, while the aqueous phase completely lacked colour. Antioxidants, when present, caused an absorbance decrease on the membrane due to their ROS scavenging action, giving rise to less DMPDQ production. The absorbance decrease on the sensor was linearly dependent on antioxidant concentration over a reasonable concentration range, enabling the simultaneous determination of OS and AOA-against ROS. The proposed antioxidant sensing method was tested in synthetic and real antioxidant mixtures, and validated against standard antioxidant capacity assays (i.e. ABTS and CUPRAC) for a variety of polyphenolic and antioxidant compounds. The dynamic linear ranges of antioxidants with the DMPD sensor in protection against hydroxyl and superoxide radicals generally varied within the micromolar to a few tens of micromolar concentration interval over one order-of-magnitude. Choosing three representative compounds in the high (epigallocatechin gallate), medium (quercetin) and low (p-coumaric acid) molar absorptivity range, the detection limits ranged within the concentration intervals of 0.2–0.9μM, 0.3–0.8μM, and 4–14μM, respectively, depending on the radical scavenged.

The Dispersion Stability of Polyacrylic Copolymers with Three Anionic Sulfonic Groups on Nano Zinc Oxide

Three anionic sulfonic groups are used as monomers to synthesize sodium polyacrylic copolymers by radical polymerization process. The anionic sulfonic groups are: sodium acrylic sulfonate (SAS), sodium styrene sulfonate (SSS) and 2-acrylamide-2-methyl propane sulfonic acid (AMPS), the redox initiator are ammonium persulfate and sodium bisulfite, the chain transfer agent is sodium bisulfite. The influence of different anionic sulfonic groups on dispersion stability of nanozinc oxide has been discussed.

Silylation of Al13-intercalated montmorillonite with trimethylchlorosilane and their adsorption for Orange II

The grafting reactions between trimethylchlorosilane (TMCS) and Al13-intercalated montmorillonite were investigated using X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, and nitrogen adsorption–desorption isotherms. The influence of solvent on the grafting process is discussed. The grafting amount of TMCS was roughly controlled by choosing different solvents. The product prepared in anhydrous ethanol has a high specific surface area and a large pore volume but a low degree of grafting modification; by comparison, the product prepared in cyclohexane has a high loading amount of silane but a low surface area. These organic–inorganic montmorillonites have an excellent adsorption capability for the removal of the anion dye, Orange II. Orange II exists in the interlayer region, not only through the electrostatic interactions between the anionic sulfonic acid groups of Orange II and the interlayer Al polycations, but also through the hydrophobic interactions between Orange II molecules and grafted silane. With particular emphasis on the absorbents prepared in cyclohexane, the removal rate of Orange II remains at 98.7% when the initial concentration is 1000mgl−1. A continuous organic phase is formed in the interlayer space of the products prepared in cyclohexane. The removal of Orange II with this adsorbent is based on both the adsorption on the interface and the partition between the water and the interlayer organic phases.

Synthesis of meta and para-substituted aromatic sulfonate derivatives of polydentate phenylazaphosphinate ligands: enhancement of the water solubility of emissive europium(III) EuroTracker® dyes.

The synthesis is described of a series of meta and para-substituted phenylsulfonate derivatives of very bright Eu(III) complexes with arylphosphinate groups and strongly absorbing arylalkynylpyridine moieties. The synthetic route involved the early introduction of trifluoroethyl esters to protect the sulfonic acid group, withstanding the use of reagents including acetyl bromide and mCPBA, and tolerating acid-catalysed esterification and Sonogashira reaction conditions. The Eu(III) complexes exhibit enhanced water solubility; their photophysical properties are not perturbed significantly by introduction of the anionic sulfonate groups.

Influences of charge of conjugated polymer electrolytes cathode interlayer for bulk-heterojunction polymer solar cells

Two fluorene-based conjugated polymer electrolyte (CPE) poly[(9,9-bis(6′-(N,N,N-trimethylammonium)hexyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)] (PFNBr) and poly[9,9-bis(4′-sulfonatobutyl)fluorene-alt-2,7-(9,9-dioctylfluorene)] sodium salt (PFSO3Na), bearing amine groups and anionic sulfonate groups on side chains respectively, are synthesized and applied as cathode interlayer in polymer solar cells. Both of the hydrophilic CPEs can well modify the interfacial properties and allow ohomic contact between the activelayer and cathode. The opposite charges exert great influence on the effective work function of cathode and interfacial interaction through the orientation of the interfacial dipole at the active layer/metal electrode interface, subsequently influence the resulting device performance. Compared with the cationic PFNBr, PFSO3Na with anionic sulfonate groups can dramatically reduce the work function of Al by accumulation of the polar groups at the PFSO3Na/Al interface to induce more favorable the interfacial dipole. The better energy alignment for electron extraction and transportation at active layer/Al interface is confirmed by a significant enhancement of VOC. The better wettability and morphology of PFSO3Na on the active layer and the more effective motion of sodium counterion further modify the barrier to facilitate electron extraction and transportation. Moreover, 14% and 22% performance enhancement can also be achieved respectively, when PFNBr and PFSO3Na are used as interlayers for low bandgap poly[N-9″-heptadecanyl-2,7-carbazole-alt-5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)] (PCDTBT)-based solar cells.

An Interference‐Free Glucose Biosensor Based on an Anionic Redox Polymer‐Mediated Enzymatic Oxidation of Glucose

Herein a novel strategy for the construction of an amperometric biosensor for highly sensitive and selective determination of glucose is described. The biosensor is made of a biocomposite membrane of glucose oxidase (GOx) and an Os(bpy)2 (bpy=2,2'-bipyridine)-based anionic redox polymer (Os-RP) mediator. The biosensor is fabricated through the co-immobilization of GOx and the Os-RP on the surface of a glassy carbon electrode by a simple one-step chemical crosslinking process. The crosslinked Os-RP/GOx composite membrane shows excellent catalytic activity toward the oxidation of glucose. Under optimal experimental conditions, a linear correlation between the oxidation current of glucose in amperometry at 0.25 V (vs. Ag/AgCl) and glucose concentration up to 10 mM with a sensitivity of 16.5 μA mM(-1) cm(-2) and a response time <5 s. Due to the presence of anionic sulfonic acid groups in the backbone of the redox polymer, the biosensor exhibits excellent selectivity to glucose in the presence of ascorbic acid and uric acid. The low hydrophobicity of the composite membrane also effectively retards the transport of molecular oxygen within the membrane.

Supramolecular cooperative-assembly of polyelectrolyte films

In this report we investigate and compare the characteristics of the cooperative-assembly of double-stranded DNA and random coil poly(styrene sulfonate) mixed with didodecyldimethylammonium bromide (DDAB). Film formation is attributed primarily to electrostatic interactions between anionic phosphate or sulfonate groups (DNA or PSS) and cationic ammonium groups of DDAB. It appears that the elasticity and morphology of such films are dependent on the length and the structure of polymers. Ethidium bromide (a nucleic acid stain and intercalating agent) was employed to probe the structure of polymers based on the photoluminescence response of this dye.

Self-doping inspired zwitterionic pendant design of radical polymers toward a rocking-chair-type organic cathode-active material

‘Self-doping’ inspired high-density redox copolymers were designed and prepared via free radical copolymerization of 2,2,6,6-tetramethyl-4-piperidyl methacrylate and vinylsulfonic acid (VSA) with a view to preventing a change in salt concentration during the one-electron oxidation of the nitroxide radicals to N-oxoammonium cations in a polymer layer. A copolymer composition of TEMPO–sulfonate anionic group = 1/1 for density-maximized charge neutralization was achieved by controlling the feed ratio of the copolymerization. The formation of copolymers was evidenced by 2D nuclear Overhauser enhanced spectroscopy (NOESY) and diffusion ordered spectroscopy (DOSY) NMR. Poly(TEMPO methacrylate-stat-VSA) was considered to have the alternating tendency due to the acid–base interaction in the comonomers, which were supported not only by the single crystal structure of the 2,2,6,6-tetramethyl-4-piperidyl methacrylate and VSA complex, but also by the 1H–1H correlation in NOE signals. In an aqueous electrolyte with 0.5 M NaCl, the copolymer electrode showed a redox response near 0.66 V (vs. Ag/AgCl), and the excellent cycle performance during 1000 cycles. During the one-electron oxidation of the nitroxide radical, anionic sulfonate groups led to charge compensation of the N-oxoammonium cation. Consequently, the copolymer electrode exhibited the cation migration, which was evidenced by mass-transfer analysis using an electrochemical quartz crystal microbalance (EQCM) technique. The copolymer could be applied as an aqueous electrolyte-type organic rechargeable device. Moreover, this design proposes the ultimate principle toward the strategy of maximizing energy density in organic charge storage devices.

Preparation and Surface Activities of Modified Double‐Tailed Anionic Surfactants

AbstractWe prepared a series of modified double‐tailed surfactants containing two identical nonionic moieties and an anionic spacer group. Each surfactant was prepared through the reaction of two moles of polyoxyethylene alkyl ether with one mole of maleic anhydride to form a diester having a gemini structure; an anionic sulfonate group was then introduced through reaction of the olefinic bond with sodium hydrogen sulfite. The structures of these compounds were confirmed through infrared spectroscopy, nuclear magnetic resonance spectroscopy, and elemental analysis. These modified double‐tailed surfactants exhibit good surface properties, including low‐foaming, wetting and lime‐soap dispersing power. Their excellent dispersing abilities toward disperse dyes were due to the double‐tailed structures of the surfactants, with the hydrophobic moieties increasing the binding ability to the dyes and its anionic units providing dispersing power.