Synthesis and aggregation properties of ethylene glycol ester-based cationic Gemini surfactants

Abstract

The gemini surfactants with ethylene glycol as a starting material were synthesized, surface tensions and aggregation properties were evaluated, the wettability on paraffin, PTFE and metaplexis leave surfaces were determined. The experimental results showed the surface tensions of gemini surfactant solutions decrease first and then stabilize with the concentration increasing. The cmc values of surfactants decrease as their hydrophobic chain length increased, with the hydrophobic chain length of 14 shown the smallest γcmc and highest surface activity among these six investigated gemini surfactants. The equilibrium contact angles of investigated surfactant solutions on three solid surfaces of paraffin, PTFE, and metaplexis decrease firstly with the increase of concentrations, and finally stabilize. The 14-2-14 solutions can change surface of metaplexis leaves from hydrophobic to hydrophilic. The contact angles of gemini surfactants on paraffin surfaces vary significantly, and all of the six synthesized gemini surfactants can change paraffin surfaces from hydrophobic to hydrophilic.