Synthesis and properties of ester functionalized cationic Gemini surfactants with amide groups

Abstract

Abstract In this paper, a novel series of ester-functionalized cationic Gemini surfactants with amide groups (abbreviated as C m -(BAE)-C m (m = 12, 14, 16)) were synthesized and their surface tension as well as the thermodynamic surface parameters were determined with conductivity and fluorescence measurements, respectively. The structures of these Gemini surfactants were characterized by FT-IR, 1H NMR, and MS. The Krafft points of the three surfactants are below 0 °C, indicating better water solubility. The critical micelle concentration (CMC) of these surfactants decreases with the increase in the length of hydrophobic chain. The micellization process of these surfactants was found to be entropy-driven. The polar functional ester groups in the spacer form hydrogen bonds with water molecules, which increases the solubility of these Gemini surfactants in aqueous systems, facilitates the aggregation of their monomers and improves the stability of their micelles.