LAUSR

Abstract A series of novel itaconic acid based asymmetrical gemini surfactants containing two long alkyl chains, two selfsame nonionic groups along with an anionic moieties covalently attached by an itaconic acid spacer group (polyoxyethylene laurinol ether sodium sulfoitaconate: PLSS- n ) have been synthesized through esterification and sulfonation reaction using itaconic anhydride (IAn) and polyoxyethylene alkyl ethers. The chemical structures of the PLSS- n homologs were confirmed through FT-IR, 1 H NMR spectra and elemental analysis (EA). And their physico-chemical properties in aqueous solutions were further investigated. The PLSS- n species have lower equilibrium surface tension ( γ CMC ) and critical micelle concentration ( CMC ), lower Krafft points ( T k ), good wettability and foaming properties. The γ CMC and CMC values of PLSS- n are decreased with the increase of the temperature. The PLSS- n homologs exhibit high surface activities even at lower temperature. The PLSS- n homologs all exhibit smaller values of areas per molecule ( A min ) and larger values of maximum excess surface concentration ( Γ max ). The rheological behaviors of the PLSS- n solutions show that only PLSS-3 shows shear thinning feature with the increasement of shear rate. The average diameters of the PLSS- n aggregations were studied by Dynamic light scattering (DLS) at 25 °C. Cryogenic transmission electron microscopy (cryo-TEM) results of the PLSS- n indicate that these gemini surfactants can form various micellar behaviors, which are affected by different combined factors. The Small angle X-ray scattering (SAXS) measurements provide evidence of the anisotropic lamellar structure.