Surface activity and foam properties of novel Gemini short-chain fluorocarbon and hydrocarbon mixed system in aqueous solutions

This work presented a systematic study on the surface activity and foam performance of Gemini short-chain fluorocarbon surfactant (Gemini) solutions mixed with anionic, zwitterion, and non-ionic hydrocarbon surfactants. The results show that Gemini exhibits good surface activity and foam properties. The compounding of Gemini and three ionic hydrocarbon surfactants presents a good synergy, and with the increase of Gemini concentration, the foam performance improved. Gemini improves the foam performance by enhancing the alignment of surface adsorbed molecules at the liquid-air interface. Among all mixed systems, the Gemini/SDS shows the strongest foam stability. Compared to single SDS aqueous solution, the foam filtration time of mixed solution increased by 182.17 % with the addition of Gemini. The average bubble area in 30 min decreases by 8.03 %-46.32 %. The addition of Gemini slightly inhibited the foam coarsening of SDS solution when the Gemini concentration was 0.01 wt%. The foam coarsening process was significantly inhibited when the Gemini concentration was 0.1 wt%. The results of the present study are meant to provide guidance for the practical application of foams generated by the mixtures of the Gemini and hydrocarbon surfactants.