Abstract:

Non-aqueous foams have wide applications in cosmetics, porous materials, biomedicine, oil and gas development, etc. However, due to the low surface tension of non-aqueous solvents, they have difficulty in foaming and their foams usually have poor stability. Therefore, relevant field has been a difficult problem to overcome. Surfactant aggregates are widely used in related field due to their high density and ordered structure. In this work, different surfactant aggregates were prepared and characterized, in which sodium dodecyl sulfonate and sodium dodecylbenzene sulfonate were used as the main agents, and formamide and decanol were used as the non-aqueous phase. Then their foaming ability and foam stability for non-aqueous solvents were observed. The results showed that all these surfactant aggregates were of layered liquid crystal structure, belonging to non-Newtonian fluids, which had shear-thinning rheological phenomenon. The higher the content of surfactant, the more stable the layered liquid crystal structure of the surfactant aggregates. The foam volume was first increased and then decreased with the increase of layered liquid crystal content. The foam-stabilizing ability of SDBS/decanol/formamide system was better than that of SDS/decanol/formamide system. When formamide was used as the non-aqueous phase and the layered liquid crystal content in the SDBS/decanol/formamide system was 60% （w/%）, the foam life was more than 55 h. When the non-aqueous phase was decanol and the layered liquid crystal content in the SDBS/decanol/formamide system was 60% （w/%）, the foam life lasted for more than 6 h.

Key words: surfactant aggregate, layered liquid crystal, stability, non-aqueous foam