Study On Foaming Properties Of Surfactant Aggregates In Non-aqueous Solvents

Non-aqueous foam refers to a dispersion system in which gas is dispersed in a nonaqueous solvent or solid.It is widely researched and applied in many industries and processes such as crude oil production and refining,polymer latex production,etc.Therefore,a reliable assessment of non-aqueous foams is essential.However,the basic theoretical research on non-aqueous foam is far less abundant,mature and valued.Surfactant aggregates lyotropic liquid crystals play a vital role in many fields due to their special structure and properties.Therefore,the article focuses on the study of foaming properties of surfactant aggregates lyotropic liquid crystals in non-aqueous solvents.Firstly,constructing surfactant aggregates lyotropic liquid crystals in non-aqueous solvents and characterizing them with polarized light microscope,cryo-electron microscopy,steady-state rheological properties and infrared.And then conducting foaming feasibility tests by mechanical stirring.Finally evaluating foam stability by foam volume and time.Through experimental analysis,the following trends were observed:(1)The two systems of surfactant aggregates lytropic liquid crystals in non-aqueous solvents oleic acid/triethanolamine and cetyltrimethylammonium bromide/glycerol will change to isotropic with increasing temperature.The others triethanolammonium oleate /p-xylene,sodium dodecyl sulfate/decanol/glycerol,sodium dodecyl sulfate/decanol/formamid,sodium dodecyl sulfate/decanol/ethylene glycol are not affected by temperature,but non-aqueous liquid crystal phase region of the sodium dodecyl sulfate systems is arranged in order by organic solvents: formamide >glycerol > ethylene glycol.(2)Hexagonal existed oleic acid/triethanolamine and cetyltrimethylammonium bromide/glycerol non-aqueous systems,showed mosaic texture and fan texture.Other four non-aqueous systems were lamellar,showed oily stripes and cross pattern.All surfactant aggregates lytropic liquid crystals in non-aqueous solvents behave as non-Newtonian fluids with shear-thinning properties,and the formation of surfactant aggregates lyotropic liquid crystal phase in non-aqueous solvents is due to theinteraction of interface molecules.(3)Surfactant aggregates lytropic liquid crystals in non-aqueous solvents oleic acid/triethanolamine and cetyltrimethylammonium bromide/glycerol don't foam at room tempe-rature but at higher temperature.And the same time,the stability of the foam at 45°C is better than 60°C.Others at room temperature,sodium dodecyl sulfate/decanol/formamid is the best one and sodium dodecyl sulfate/decanol/ethylene glycol is the worst one.(4)The non-aqueous foam stability of the three surfactant aggregates lytropic liquid crystals systems included sodium dodecyl sulfate series is: sodium dodecyl sulfate/decanol/formamid > sodium dodecyl sulfate/decanol/glycerol > sodium dodecyl sulfate/decanol/ethylene glycol,which is consistent with the order of the liquid crystal phase region.(5)Surfactant aggregates lytropic liquid crystals in non-aqueous solvents cetyltrimethylammonium bromide/glycerol at 45? and sulfate/decanol/formamid at room temperature are super-stable foam systems,and foam continued to decay for more than 20 days.(6)The formation of surfactant aggregates lytropic liquid crystals in non-aqueous solvents is a decisive factor for the stable foam.