Synthesis and interfacial properties of ethoxylated cationic surfactants derived from n-dodecyl glycidyl ether

• Cationic surfactants have been synthesized to improve solubility in water by adding ethylene oxide as a hydrophilic group to the intermediates of di-hydroxyl cationic surfactant molecules.
• The structure of the resulting products was elucidated by 1H NMR and FT-IR.
• The interfacial properties, such as CMC, surface tension, interfacial tension, contact angle and foam stability were measured.

In this study, cationic surfactants were synthesized to improve solubility in water by adding ethylene oxide as a hydrophilic group to the intermediates of di-hydroxyl cationic surfactant molecules. The structure of resulting product was elucidated by 1H NMR, FT-IR and HR/MS. The CMCs of BA-2-MA and BA-5-MA surfactants were found to be 9.01 × 10−4 and 4.92 × 10−3 mol/L respectively and the surface tensions at their CMC conditions were 28.64 and 32.22 mN/m respectively. The interfacial tensions measured between 1 wt% surfactant solution and n-decane were found to be in the same order of magnitude as those exhibited between micellar solutions and nonpolar oils.

Figure optionsDownload as PowerPoint slideSynthetic route of ethoxylated cationic surfactants where R = C12H25, m + n = 2 for BA-2EO, and m + n = 5 for BA-5EO.