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Thermodynamic Properties of Sulfobetaine‐Type Surfactants
Author(s) -
Zhu Hailin,
Hu Zhiyong,
Wang Jianlong,
Cao Duanlin
Publication year - 2014
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/s11743-013-1503-z
Subject(s) - chemistry , adsorption , aqueous solution , thermodynamics of micellization , critical micelle concentration , enthalpy , alkyl , micelle , amine gas treating , inorganic chemistry , organic chemistry , thermodynamics , physics
Sulfobetaine‐type surfactants containing a hydroxy group were synthesized by the reaction of long chain monoalkyl dimethyl tertiary amine with 3‐chloro‐2‐hydroxypropanesulfonic acid sodium salt. The structures were characterized by 1 H NMR and ESI‐MS. Their critical micelle concentrations (CMC) in aqueous solution were determined by the plate method in the temperature rang from 298.15 to 328.15 K. The thermodynamic parameters of micellization ( Δ G mic θ, Δ H mic θand Δ S mic θ) and surface adsorption ( Δ G ad θ, Δ H ad θand Δ S ad θ) were calculated from CMC data. The results showed that the micellization and surface adsorption of these surfactants in aqueous solution was a spontaneous and entropy‐driven process. The micellization and surface adsorption became easier when the alkyl chain length increased from 12 carbon atoms to 14. The enthalpy–entropy compensation of micellization and adsorption was investigated. The compensation temperature were found to be (311 ± 2) K for both micellization and adsorption. The Δ H mic ∗and Δ H ad ∗decreased, but the Δ S mic ∗and Δ S ad ∗increased with increasing the hydrophobic chain length from 12 to 14.