Effects of calcium ions on solubility and aggregation behavior of an anionic sulfonate gemini surfactant in aqueous solutions

► The anionic gemini surfactant 12-3-12(SO3)2 shows excellent tolerance to Ca2+ in water. ► Aggregates in clear solutions lead to precipitates with similar morphologies. ► Wormlike micelles are observed in concentrated Ca2+/12-3-12(SO3)2 clear solutions. ► Stacking of long wormlike micelles produces fiber based precipitate structures. ► The larger aggregates are well dispersed in aqueous solution and also complex Ca2+.