Interfacial tension, wettability, foam and emulsification properties of mono- and di-tetrapropylene diphenyl ether disulfonates

Synthesis of Fatty Alcohol Ether Carboxylic Ester Surfactant and its Performance in an Anionic/Non-Ionic Mixed System

A salt-type fatty alcohol ether carboxylic ester (AECE-Na) surfactant with both anionic and non-ionic characteristics was synthesised using a fatty alcohol ether (AEO) and succinic anhydride. Compared with traditional synthetic methods, neither irritating substances (chloroacetic acid and chloroacetate) nor precious metals (Pt and Pd) were used in the synthesis, which is a simple, economic, and green method. FT-IR and 1H NMR spectroscopies and MALDI TOF mass spectrometry were used to prove the molecular structure of the target product AECE-Na. In addition, the surface activities, intermolecular interactions, application properties, and aggregation behaviours of the individual systems (AEO and AECE-Na) and the anionic/non-ionic mixed system (AECE-Na/AEO) were investigated. The results showed that AECE-Na/AEO exhibits synergistic effects in terms of surface tension reduction efficiency, wetting, emulsification, foaming, and detergency compared with the individual systems.

Synthesis and Properties of Novel Catanionic Surfactant Phosphonium Benzene Sulfonate

A new type of catanionic surfactant phosphonium benzene sulfonate was synthesized by quaternization of triphenyl phosphine with dimethyl carbonate and followed by anion exchange with alkyl benzene sulfonic acid. The molecular structure was characterized by FT-IR, 1H-NMR, and 31P-NMR. The thermal stability of phosphonium benzene sulfonate was evaluated by thermogravimetric analysis (TGA). Its surface properties were studied systematically through equilibrium surface tension, electrical conductivity, and dynamic surface tension measurements. The wettability, foam properties, and emulsification of phosphonium benzene sulfonate were estimated in this paper. TGA results revealed that it has an excellent thermostability and could be used below 350 °C. Equilibrium surface tension results indicated that it has a low critical micelle concentration (CMC, about 0.10 mmol/L), lower than that of ammonium benzene sulfonate and sodium dodecyl benzene sulfonate. Furthermore, the micellization of phosphonium benzene sulfonate in aqueous solution is an entropy-driven spontaneous process. The adsorption process of phosphonium benzenesulfonate at the air-liquid interface is controlled by hybrid kinetic adsorption. Moreover, it has excellent wetting and emulsifying properties and low foam properties.

Wettability of Phosphonium Benzene Sulfonate on Parafilm

The wettability of phosphonium benzene sulfonate on parafilm has been investigated by means of dynamic contact angle measurement. Based on the surface tension data, the spreading coefficient, adhesion tension (γlg cosθ), and adhesion work (WA) were further analyzed. It was revealed that the surface tension and contact angle decreased with the increase in concentration, and remained constant when the concentration was higher than the critical micelle concentration (CMC). Furthermore, the spreading coefficient increased with increase in concentration then stays unchanged. In the studied concentration range, the value of spreading coefficient is negative, indicating that it cannot rapidly spread the surfactant on the parafilm surface to an uniform film. The measurements show a linear relationship between the adhesion tension γlg cosθ and the surface tension in the concentration range of 2 × 10−6 mol L−1 to 1 × 10−4 mol L−1. The adsorbed amount of surfactant molecules at the parafilm-solution interface is lower than that at the gas-liquid interface. The value of WA was initially decreased then increased as the concentration was increasing and reaches a minimum value at the concentration near the CMC.