Synthesis, characterization, and physicochemical properties of a series of quaternary gemini surfactants with different spacer lengths

摘要

The study deals with the synthesis and characterization, as well as the adsorption and micellization behavior (including thermodynamics) in aqueous solution of a series of gemini surfactants with different spacer lengths. The synthesized surfactants were characterized by FTIR, H-1-NMR, FESEM, EDX, and TGA analyses. DLS measurements showed that micelles formed at critical micelle concentration (CMC) transformed into an assemblage of micelles and micellar agglomerates at higher concentrations. Surface tension was found to decrease with temperature and spacer length. However, CMC values increased with spacer length, as confirmed by surface tension and conductivity results. Surface adsorption parameters such as surface excess, minimum area, surfactant effectiveness, and efficiency were also determined. Gibbs free energy of adsorption (Delta G (ads)) value was found to be greater than Gibbs free energy of micellization (Delta G (mic)), showing that adsorption is more favored in aqueous gemini systems.