Novel Quaternary Ammonium-Based Cationic Surfactants: Synthesis, Surface Activity and Evaluation as Corrosion Inhibitors for C1018 Carbon Steel in Acidic Chloride Solution

Synthesis and Aggregation Behavior of Hexameric Quaternary Ammonium Salt Surfactant Tz-6C12QC

A hexameric quaternary ammonium salt surfactant Tz-6C12QC featuring a rigid triazine spacer and six ammonium groups was synthesized. The molecular structure and aggregation behavior of Tz-6C12QC were characterized by nuclear magnetic resonance spectroscopy, surface tension, conductivity, dynamic light scattering, and transmission electron microscopy, etc. Dissipative particle dynamics (DPD) simulation was employed to investigate the self-assembly behavior of Tz-6C12QC at different concentrations. The rheological behavior of the polyacrylamide/Tz-6C12QC system was characterized by shear rheology. The results indicated that Tz-6C12QC exhibited superior surface activity and lower surface tension compared to conventional surfactants. Rheology analysis revealed that Tz-6C12QC had a significant viscosity reduction effect on polyacrylamide. DLS and TEM indicated that, as the concentration of Tz-6C12QC increased, monomer associations, spherical aggregations, vesicles, tubular micelles, and bilayer vesicles were sequentially formed in the solution. This study presents a synthetic approach for polysurfactants with a rigid spacer and sheds light on the self-assembly process of micelles.

The performance of three novel Gemini surfactants as inhibitors for acid steel corrosion: experimental and theoretical studies

Adipic acid was used to synthesize three nonionic Gemini surfactants containing different numbers of propylene oxide units in their structures. The produced surfactants have been characterized employing FTIR and 1H-NMR spectra. Some of the physical properties of them, namely, surface tension, maximum surface excess concentration, surface pressure, critical micelle concentration, and the minimal area of the surface taken by a single molecule, were computed. The inhibitory effect of the synthesized surfactants on the corrosion of C-steel (C45) in 1.0 M HCl solution was studied. Gravimetric and electrochemical methods were used for corrosion rate measurements. The outcomes acquired from the used methods showed that every one of the three surfactants works as a strong inhibitor for steel acidic corrosion. By raising surfactant concentration and exposure time, the inhibition proficiency improves. The inhibition efficiency exceeded 90% for the three compounds. The higher the propylene oxide units contained in the surfactant molecule the higher is its inhibition efficiency. Based on the findings, a mechanism for inhibitory action was proposed. Moreover, the density functional theory (DFT) and molecular electrostatic potential (MEP) were investigated for the three inhibitors. The calculated parameters were correlated with the inhibition efficiency.

Application of surfactants as anticorrosive materials: A comprehensive review

Corrosion is the degradation of a metal due to its reaction with the environment. One of the most efficient ways of securing metal surfaces from corrosion is the use of corrosion inhibitors. Their efficacy is connected to their chemical composition, their molecular structures, and their adsorption affinities on the metal surface. This review article focuses on the prospects of different types of monomeric and gemini surfactants, mixed surfactants systems, surfactants- additives mixed systems, inhibitors-surfactants (as additives) mixed systems, and ionic liquid based surfactants as promising corrosion-inhibiting formulations in the aqueous phase and the role of surfactants in developing protective coatings. The analysis starts with an accurate overview of the characteristics, types, and structure-property-performance relationship of anti-corrosion formulations of such inhibitors.