Synthesis,Micellization, and Surface Activity of Novel Linear-Dendritic Carboxylate Surfactants |
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| Authors: | Yuning Lou Yajuan Dong Xiaoyong Wang Feirong Gong Min Zhao Zongming Rong |
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| Affiliation: | 1. School of Chemistry & Molecular Engineering, East China University of Science and Technology, Shanghai, 200237 China
These two co-first authors contributed equally to this work.;2. School of Chemistry & Molecular Engineering, East China University of Science and Technology, Shanghai, 200237 China;3. School of Materials Science & Engineering, East China University of Science and Technology, Shanghai, 200237 China |
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| Abstract: | Two generations of novel linear-dendritic carboxylate surfactants C18-G1-(COONa)2 and C18-G2-(COONa)4 have been synthesized by the divergent method and their structures are characterized by 1H Nuclear Magnetic Resonance and Infrared analysis. The electrical conductivity measurement is used to measure the Krafft temperatures of C18-G1-(COONa)2 and C18-G2-(COONa)4, which are much smaller than those of the corresponding conventional surfactant sodium stearate. The markedly enhanced solubility of two linear-dendritic surfactants is ascribed to the high hydrophilicity of surfactant headgroups induced by the carboxylate and ester groups. The critical micelle concentration (CMC) values obtained from both the electrical conductivity and surface tension measurements indicate that the micellizations of linear-dendritic surfactants become favorable with the increase in the number of the surfactant headgroup. However, the surface activity parameters including the surface tension at the CMC, maximum surface excess, and minimum surface area reveal that C18-G1-(COONa)2 exhibits greater efficiency in absorbing at the air/water interface compared to C18-G2-(COONa)4, owing to their different steric repulsions of the surfactant headgroups. In addition, C18-G1-(COONa)2 and C18-G2-(COONa)4 have higher emulsifying ability than the conventional surfactants sodium stearate and sodium octadecyl sulfate. |
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| Keywords: | Linear-dendritic surfactant Krafft temperature Micellization Electrical conductivity Surface tension |
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