The effect of the spacer rigidity on the aggregation behavior of two ester-containing Gemini surfactants

► Two Gemini surfactants and their monomeric surfactant were synthesized. ► The rigidity was isolated from the other properties of the spacer. ► The surfactant with rigid spacer showed a higher surface activity. ► The dependence of the thermodynamics of aggregation on the rigidity was discussed. ► Different aggregation morphologies were found for different spacer rigidities.