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.