Impact of polyethylene glycol on aqueous micellar solutions of sodium oleate studied by small-angle neutron scattering

Studies on the Surface Adsorption of Binary Molten Salts

The surface adsorption of eight binary molten salts, AgNO3-M1NO3(M1 = Li, Na, K, Rb), NaNO3-M2NO3 (M2 = K, Rb), Ca(NO3)2-CsNO3, and Cd(NO3)2-NaNO3, has been investigated. It is found that the surface tension and temperature of molten salts at constant pressure and mole fraction satisfy the same equation as that for pure liquid compounds reported in our previous works. The heats of phase transition from the bulk to the surface phase for eight molten salts are determined. The heats per unit area are all at the order of -10-2 J/m2. The phase transition is exothermic because the entropy in the surface phase is smaller than the entropy in the bulk phase. The ratio of the solute surface concentration to the solute bulk concentration is approximated as the first-order polynomials of the solute bulk concentration. Then, curves of the surface tension vs the solute bulk concentration are well fitted. The ratio (ΔcBs/ΔcBα) is used to interpret the changing trend of the surface tension with bulk concentrations of solute. It is also found that the surface tension of molten salts decreases linearly with the solute surface concentration.

Structure and Intermolecular Interactions in Aqueous Solutions of Polyethylene Glycol

Aqueous solutions of polyethylene glycol are studied by small-angle neutron scattering over a broad range of polymer molecular masses and concentrations. The scattering data were modeled by a Gaussian chain form factor combined with random phase approximation, which provided good fits over the whole studied concentration range. The results showed that polyethylene glycol in the molecular mass range 0.4–20 kDa in water at physiological temperature T = 37 °C behaves like a random coil in nearly theta solvent conditions. The obtained results serve as a reference for the description of complex mixtures with PEG used in various applications.

Magnetic Nanoparticle Systems for Nanomedicine—A Materials Science Perspective

Iron oxide nanoparticles are the basic components of the most promising magneto-responsive systems for nanomedicine, ranging from drug delivery and imaging to hyperthermia cancer treatment, as well as to rapid point-of-care diagnostic systems with magnetic nanoparticles. Advanced synthesis procedures of single- and multi-core iron-oxide nanoparticles with high magnetic moment and well-defined size and shape, being designed to simultaneously fulfill multiple biomedical functionalities, have been thoroughly evaluated. The review summarizes recent results in manufacturing novel magnetic nanoparticle systems, as well as the use of proper characterization methods that are relevant to the magneto-responsive nature, size range, surface chemistry, structuring behavior, and exploitation conditions of magnetic nanosystems. These refer to particle size, size distribution and aggregation characteristics, zeta potential/surface charge, surface coating, functionalization and catalytic activity, morphology (shape, surface area, surface topology, crystallinity), solubility and stability (e.g., solubility in biological fluids, stability on storage), as well as to DC and AC magnetic properties, particle agglomerates formation, and flow behavior under applied magnetic field (magnetorheology).

Investigation of pseudo-polyanion formation between polyvinylpyrrolidone and sodium dodecanoate in aqueous solution by capillary electrophoresis, conductometry, tensiometry and calcium stability

H-bonding replaces sodium bridging in the PVP–SD complexation with pH reduction.

Different pH triggered aggregate morphologies in sodium oleate–cationic surfactants mixed systems

The unusual effect of pH on the aggregate morphology of pH dependent surfactant systems.