Correlation of Dynamic Surface Tension with Sedimentation of PTFE Particles and Water Penetration in Powders

Synthesis and Properties of Lauryl Phosphate Monoester

Lauryl phosphate monoester was synthesized from the starting materials lauryl alcohol and phosphoric acid without catalysts. Subsequently, the crude product was purified by recrystallization and characterized by Fourier transform infrared (FT-IR) and nuclear magnetic resonance (31P-NMR). From the results, it was apparent that the synthesized material was the desired target product. Lauryl monoester potassium phosphate reduced the surface tension of water to 25.08 mN/m at a critical micelle concentration (CMC) of 0.569 mmol/L. It showed a low contact angle and had a low surface tension, indicating a good hydrophilicity. Lauryl monoester potassium phosphate also showed excellent antistatic properties, however its emulsifying ability was not good. The size of the aggregates of lauryl monoester calcium phosphate in aqueous solution was 220 nm and their morphology was spherical.

Thermodynamics of Micellization, Interfacial Behavior and Wettability Alteration of Aqueous Solution of Nonionic Surfactants

The present work deals with the physiochemical properties of polyoxyethylene sorbitan fatty acid esters (polysorbates), which are commonly known under the trade name Tween. Thermodynamics of micellization and adsorption at air-water interface for these nonionic surfactants solutions have been studied over a broad range of temperature. As the temperature of the surfactant solutions increases, the surface tension decreases whereas the critical micelle concentration (CMC) of each surfactant solution initially decreases and then increases. The free Gibb free energies of the micelle formation Δ G m o $\Delta {\rm{G}}_{\rm{m}}^{\rm{o}}$ , and the surfactant adsorption Δ G ads o $\Delta {\rm{G}}_{{\rm{ads}}}^{\rm{o}}$ , are calculated for the CMC of each surfactant at different temperatures. The surface or expanding pressure (Πcmc), minimum area per molecule (Amin), maximum surface excess (Γmax) are also calculated. The interfacial tension (IFT) between the aqueous surfactant solutions and the crude oil are measured at different concentrations of the surfactants using a spinning drop tensiometer. The contact angles are determined on an oil wet quartz surface to investigate the wettability alteration in the presence of Tween surfactants with varying salinity. FTIR analysis of quartz at dry and oil wet state, crude oil and COBRS (crude oil-brine-rock-surfactant) combinations are performed to identify the associated functional groups and their mutual interactions.

Switchable foam control by a new surface-active ionic liquid

Switchable foam control was achieved for aqueous solution of new surface-active ionic liquid ([BAzoTMA][NTf₂]) by alternatively adding cucurbit[7]uril and spermine.