Volumetric and Viscosity Properties of MgSO₄/CuSO₄ in Sucrose + Water Solutions at 298.15 K

Apparent molar volumes VΦ,E for MgSO4, CuSO4, Na2SO4, NaCl, MgCl2, and CuCl2 and viscosity B-coefficients for MgSO4/CuSO4 in sucrose + water solutions were determined from density and viscosity measurements at 298.15 K. Infinite-dilution apparent molar volumes VΦ,E0 for Na2SO4, NaCl, MgCl2, and CuCl2 in sucrose + water solutions were evaluated. The VΦ,E0 values for MgSO4 and CuSO4 were obtained by an additivity method. An empirical equation VΦ,E = ∑i=0n ∑j=0m Pij miSmj/2E was used to relate the apparent molar volumes of MgSO4/CuSO4 to the molalities (mE and mS). Volumetric interaction parameters were also obtained from the transfer volumes of electrolytes. Activation energies ΔμE0⧺ were also calculated from the viscosity B-coefficients. Results show that the values of standard transfer volumes, viscosity B-coefficients, and ΔμE0⧺ are positive and increase usually with increasing sucrose content

Conductivities of CuSO₄ and CdSO₄ in Sucrose/Trehalose−Water Systems at 298.15 K

The conductivities of CuSO4 and CdSO4 in aqueous disaccharide (sucrose and trehalose) solutions were measured together with the densities, viscosities, and relative dielectric constants of the aqueous disaccharide solutions at 298.15 K. The limiting molar conductivities (Λ0) and association constants (KA) were derived from the Lee−Wheaton conductivity equation. From the obtained conductivity data, the values of the Walden product (Λ0η0) were also calculated. The ion−ion and ion−solvent interactions are discussed

Individual Ionic Activity Coefficients of Sodium Halides in Glucose−Water Solutions at 298.15 K

The individual ionic activity coefficients of sodium halides (NaX) in the NaX−glucose−water solutions were experimentally determined at 298.15 K by using ion selective electrodes. The individual ionic activity coefficients evaluated by the use of the extended DebyeHückel equation are in agreement with those by the Pitzer equation. In addition, dependences of the individual ionic activity coefficients upon molalities, properties of cations and anions are discussed

Interactions of Sodium Halides with Sugars in Water: A Study of Viscosity and ¹H Spin−Lattice Relaxation Time

Viscosity B-coefficients for sodium halides (NaX, X− = Cl−, Br−, and I−) in aqueous monosaccharides (d-glucose, d-galactose, d-xylose, and d-arabinose) were determined from density and viscosity (η) measurements at 298.15 K. The contributions of solvent property (B1) and the electrolyte−solvent interaction (B2) to the B-coefficient were also obtained together with molar activation energies (ΔμE0≠) of the electrolytes for viscous flow of the aqueous saccharide−electrolyte solution. In addition, 1H spin−lattice relaxation times (T1) were measured for two glycosides in D2O with and without sodium halides. The results show the interactions between X− and the saccharides are in the following order: Cl− > Br− > I−. A linear relationship is observed between the relaxation rate (1/T1) and electrolyte concentration

Conductivities of 1‑Alkyl-3-methylimidazolium Chloride Ionic Liquids in Disaccharide + Water Solutions at 298.15 K

Conductivities for ionic liquids (ILs) 1-alkyl-3-methylimidazolium chloride ([C_<i>n</i>mim]­Cl, <i>n</i> = 4, 6, 8, 10) + sucrose + water solutions and [C₄mim]­Cl + maltose + water solutions were measured at 298.15 K. Meanwhile, densities, viscosities, and relative permittivities for water + disaccharide mixtures were also measured. The Lee–Wheaton conductivity equation was used to acquire the limiting molar conductivities (Λ₀). The Walden products (Λ₀η₀) were also calculated. The interaction of ILs with disaccharide was discussed in terms of the structure of disaccharides and ILs. Furthermore, values of Λ₀ for inorganic salts (ordinary electrolyte, such as NaCl/KCl) and ILs (special electrolyte) were compared, indicating that they have approximate limiting molar conductivities, namely, they have not too much difference in electrical conductivity

Activity Coefficients of [C_<i>n</i>mim]Br (<i>n</i> = 3 to 8) Ionic Liquids in Aqueous Fructose Solution at <i>T</i> = 298.15 K

Activity coefficients of the 1-alkyl-3-methylimidazolium bromide [C_<i>n</i>mim]Br (<i>n</i> = 3 to 8) ionic liquids (ILs) in fructose + water mixed solvents at 298.15 K were determined by cell potential measurements. The molalities of [C_<i>n</i>mim]Br ranged from (0.005 to 0.1) mol·kg^–1 and those of fructose from (0.2 to 0.8) mol·kg^–1. Gibbs free energy interaction parameters were also obtained together with salt constants. The interactions between [C_<i>n</i>mim]Br and fructose are mainly controlled by electrostatic interactions. Gibbs free energy interaction parameters (<i>g</i>_ES) and salting constants (<i>k</i>_S) are negative for the ILs (<i>n</i> = 3 to 6), indicating fructose are salted-in by the ILs in water, whereas fructose are salted-out by the ILs (<i>n</i> = 7 and 8)

Sodium Fluoride-Assisted Hydrothermal Exfoliation of Graphite into Graphene as Filler of Epoxy Resin Coating To Protect Aluminum

The low yield of graphene in the sonication-assisted aqueous-phase exfoliation is one of the challenges to its large-scale production in industry. Here, we report that hydrothermal exfoliation of graphite into graphene in NaF and polyether F127 (F127) solution can achieve a high concentration (0.55 mg mL–1) or yield (8.2%) of graphene in a low-cost, environmentally friendly manner. The defect of as-exfoliated graphene is comparable to that produced by the sonication-assisted exfoliation. In the exfoliation process, NaF and F127 are regarded as the intercalator and stabilizer. The thermal motion of H2O and F–/Na+ ion pairs, Brownian motion of graphite particles, and thermally agitation of graphite interlayers are the main driving force for exfoliating graphite. In addition, as filler of epoxy resin (EP), the graphene can enhance considerably the anticorrosion performance of EP coating. The hydrothermal exfoliation in NaF and F127 solution provides a new choice for the large-scale production of graphene

Supramolecular Vector/Drug Coassemblies of Polyglycerol Dendrons and Rutin Enhance the pH Response

A coassembly strategy for a supramolecular vector/drug was proposed with a biocompatible ternary dodecyl-bi­(third-generation polyglycerol (PG) dendrons) (C12-(G3)2) amphiphile, dodecyl sulfobetaine (SB3-12) surfactant, and poorly water-soluble drug rutin. C12-(G3)2 and rutin will mutually enhance their pH response by protonation and deprotonation of dendritic PG and rutin’s ionization as the pH changes from the acidic gastric lumen to the weakly alkaline intestine. SB3-12 may increase the payload and bring about sustained release for rutin by intermolecular interactions. Self-assembling behaviors of C12-(G3)2, SB3-12, sodium dodecyl sulfate (SDS), and dodecyl tri­methyl­ammonium bromide (DTAB) and their hybrids with rutin were characterized by UV–vis spectroscopy, a fluorescence probe, and 1H NMR. UV–vis and 1H NMR were used to identify the position and orientation of rutin in the vectors. The functions of the vector/drug were confirmed by measuring the solubility and in vitro release of rutin. The ternary coassembling vector/drug easily imparted functions of pH-responsive and sustained release without complex synthetic processes. The nanocaves framed by PG dendrons in the micelles provide pH-responsive compartments for rutin and SB3-12 in the supramolecular vector/drug anchors that accommodate rutin by weak interactions. The finely matched supramolecular vector/drug coassemblies exhibit the pH-responsive function for a potential application in the treatment of inflammatory bowel disease

Thiosalicylic Acid Modified Graphene Aerogel as Efficient Electrode Material for Ionic Liquid Electrolyte-Based Supercapacitors

Balancing energy density and power density of supercapacitors is highly desired to extend their application range. The development of new electrode materials with efficient electron/ion migration channels and large surface area accessible by the ionic liquid (IL) electrolyte with high stable potential window is a critical way to construct the high-performances of supercapacitors. In this work, a thiosalicylic acid modified graphene aerogel (TGA) was prepared by hydrothermal treatment of a graphene oxide precursor using thiosalicylic acid (TSA) as reductant, sulfur-dopant, and modifier. As-prepared TGA material has hierarchically porous texture with wide pore size distribution range and large accessible surface area by IL electrolytes, which is beneficial to the rapid diffusion and adsorption of IL electrolyte ions with larger ion sizes and high viscosity. Therefore, the TGA material possesses high specific capacitance and rate capability. Using 1-butyl-3-methylimidazolium bis­[(trifluoromethyl)­sulfonyl]­imide ([Bmim]­[Tf2N]) IL electrolyte, the assembled symmetric TGA-based supercapacitor can deliver energy densities of 115–28 Wh kg–1 within power densities of 946–11586 W kg–1. The current work provides a feasible avenue to accomplish the balance between energy density and power density of supercapacitors via the design and synthesis of hierarchically porous graphene aerogels containing doped-heteroatoms and matching with IL electrolyte

Relative Permittivities for the Galactose + Glycine + Water Solution from (278.15 to 313.15) K

Relative permittivities for the galactose + glycine + water solution have been measured from (278.15 to 313.15) K. Results indicate that the logarithmic values of the relative permittivities for the glycine + water solution increase with increasing molalities of glycine and decrease as the temperature rises. At given molalities, the relationship of the relative permittivity to the temperature can be expressed by a quadratic equation. At given temperatures and compositions of glycine, the dependence of the relative permittivities on the mole fraction of galactose can be described by a linear equation. At a given temperature and composition of galactose, the relationship between the relative permittivities and the mole fraction of glycine can be expressed by a quadratic equation. An empirical equation is proposed and used to relate log ε for the ternary solution to the temperature and compositions of the solution