Syntheses, surface activities and aggregation morphologies of a series of novel itaconic acid based asymmetrical gemini surfactants

A series of novel itaconic acid based asymmetrical gemini surfactants containing two long alkyl chains, two self-same 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 PISS-n homologs were confirmed through FT-IR, H-1 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 (gamma(CMC)) and critical micelle concentration (CMC), lower Krafft points (T-k), good wettability and foaming properties. The gamma(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 (Gamma(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 degrees C. Cryogenic transmission electron microscopy (cryo-TEM) results of the PISS-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. (C) 2019 Elsevier B.V. All rights reserved.