Study On The Mixed Systems Of X-type Gemini Surfactants And Conventional Surfactants

Due to their strong surface activity, unique structure and properties and broad applicationprospects, Gemini surfactant has attracted much attention. One of the most important reasonof Gemini surfactant application restrictions is that its production cost is expensive, therefore,it has practical value to explore the efficient compound system of the mixture containingGemini component and branch out the function of the mixture, which make Geminisurfactants serve as a kind of special-purpose additives applied to industrial production.In this paper, the equilibrium surface tension of the mixture of X-type Gemini surfactants（XC₈and IXC₈） and conventional anionic surfactant （SDS） or cationic surfactants (C₁₂TAB,C₁₄TAB, and C₁₆TAB) were measured at different temperatures （25℃,30℃,35℃and40℃）. Their respective CMC, γCMC, pC₂₀, β^αand β^mwere obtained, and researched the molecularinteraction of the mixtures, explored their synergistic effect. The results show that the CMC ofthe mixtures increases after first decreased with the increase of temperature from25℃to40℃. With the increase of the hydrophobic chain length of surfactant from C₁₂TAB to C₁₆TAB,the CMC of Gemini/C_nTAB is gradually reduced, γCMCand pC₂₀gradually rise. Thesynergistic effect of Gemini/C_nTAB is higher than that of Gemini/SDS.And the dynamic surface tension of the mixture of XC₈and SDS or C_nTAB at30℃andthe dynamic adsorption mechanism were studied. The results show that the adsorption processis in line with hybrid control adsorption mechanism when the total concentration c=0.5CMC,that is the concentration of system is less than CMC. When the concentration of system ismore than CMC, The greater the concentration, the greater the micelle dissociation rateconstant k, namely the micelle is easier to disintegrate. The effectiveness of Gemini/C_nTAB isbetter than that of Gemini/SDS, that is to say, the adsorption rate is faster and the micelle is more stable.