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Synergistic Behavior and Microstructure Transition in Mixture of Zwitterionic Surfactant, Anionic Surfactant, and Salts in Sorbitol/H 2 O Solvent: 1. Effect of Surfactant Compositions
Author(s) -
Fan Yaxun,
Tang Haiqiu,
Wang Yilin
Publication year - 2017
Publication title -
journal of surfactants and detergents
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.349
H-Index - 48
eISSN - 1558-9293
pISSN - 1097-3958
DOI - 10.1007/s11743-017-1929-9
Subject(s) - chemistry , micelle , pulmonary surfactant , aqueous solution , solvent , rheology , micellar solutions , inorganic chemistry , chemical engineering , organic chemistry , thermodynamics , biochemistry , physics , engineering
The phase behavior and rheological properties of a multi‐component system, made of a zwitterionic surfactant cocoamidopropyl betaine (CAPB), an anionic surfactant sodium lauryl sulfate (SLSS), and mixed salts (tetrasodium pyrophosphate, sodium acid pyrophosphate, sacharrin, and sodium fluoride) in sorbitol/H 2 O mixed solvent at different mass fraction of SLSS ( X SLSS ) were systematically investigated by steady and dynamic rheology, dynamic light scattering, and diffusion ordered spectroscopy (DOSY). When fixing the salt concentration and the mass ratio of sorbitol in mixed solvent ( R ), the zero‐shear viscosity increases first and then decreases showing a maximum with increasing X SLSS , resulting from the formation and entanglement of wormlike micelles. Especially when X SLSS is between 0.33 and 0.80, the mixture is dominated by entangled wormlike micelles coexisting with small micelles and separated wormlike micelles, and shows high viscoelasticity. The maximum of the zero‐shear viscosity is ca. 5 orders of magnitude larger than that of sorbitol/H 2 O mixed solvent or the CAPB/SLSS aqueous solution. The characteristic structural parameters for the micellar solutions at different X SLSS are also estimated from further analysis of the rheological results, and indicate the stronger network structures of the wormlike micelles are formed in our systems compared with the wormlike micelles formed by a traditional zwitterionic/anionic surfactant aqueous solutions. The great improvements of rheological properties are attributed to the strong screening effects of the mixed salts and the strong solvophobic effect of sorbitol on the electrostatic and hydrophobic interaction between the CAPB and SLSS molecules. The present work has improved our understanding about the aggregation behavior of zwitterionic/anionic mixed surfactants with salts in less polar solvent/H 2 O mixture, which would be of widely practical importance to optimize the formulation of products for personal care and household cleaning.