Branched-chain anionic surfactants with same hydrophobic tail architecture: effects of hydrophilic headgroups

Abstract The branching of the hydrophobic tail has a significant impact on the performance of branched-chain surfactants, while the influence of hydrophilic headgroups on the surface properties of branched-chain anionic surfactants is rarely reported. In this work, three branched-chain anionic surfactants with the same carbon number and hydrophobic tail architecture but different hydrophilic groups, C 8 sodium branched-chain alkylsulfonate (C 8 SBCAS), C 8 sodium branched-chain alkylphosphonate (C 8 SBCAP), C 8 sodium Guerbet alcohol sulfate (C 8 SGAS) with sulfonate, phosphonate and sulfate groups, respectively, were synthesized. Their surfactant properties, including equilibrium surface tension, dynamic surface tension, wetting ability and foaming property, were thoroughly investigated. The order of the critical micelle concentration ( CMC ) is C 8 SGAS < C 8 SBCAP < C 8 SBCAS, and the equilibrium surface tension ( γ CMC ) follows the order C 8 SBCAP < C 8 SBCAS < C 8 SGAS. These results indicated that increasing the polarity of the hydrophilic headgroups and weakening the charge effect could reduce the hydrophobicity of surfactants, thereby improving their wetting ability and foaming properties. This study provides new insights into the influence of hydrophilic headgroups on the properties of branched-chain anionic surfactants to meet the specific needs of different sectors.