A responsive anionic wormlike micelle using pH-directed release of stored sodium based on polybasic acids. Issue 24 (4th June 2018)

• Record Type: Journal Article
• Authors: Wang, Pengxiang; Kang, Wanli; Tian, Shujie; Yin, Xia; Zhao, Yilu; Hou, Xiaoyu; Zhang, Xiangfeng; Yang, Hongbin
• Is Part Of: Soft matter. Volume 14:Issue 24(2018)
• Page Start: 5031
• Page End: 5038
• Publication Date: 2018-06-04
• Subjects: Soft condensed matter -- Periodicals; 530.413
• DOI: 10.1039/c8sm00944a
• Languages: English
• ISSNs: 1744-683X

Abstract

Abstract : The ability of polybasic acids to release and store Na + was used to develop a differential pH-responsive wormlike micelle. Abstract : Responsive wormlike micelles are very useful in a number of applications, whereas it is still challenging to create dramatic viscosity changes in anionic surfactant systems. Here a differential pH-responsive wormlike micelle based on sulfonic surfactants was developed, which is formed by mixing sodium dodecyl trioxyethylene sulphate (SDES) and ethylenediaminetetraacetic acid tetrasodium (EDTA 4− ·4Na + ) at the molar ratio of 1 : 1. The phase behavior, aggregate microstructure and viscoelasticity of the SDES/EDTA 4− ·4Na + solution were investigated via macroscopic observation, cryo-TEM and rheological measurements. It was found that the phase behavior of the SDES/EDTA 4− ·4Na + solution undergoes transitions from a water-like fluid to viscoelastic upon decreasing the pH. On decreasing the pH from 12.01 to 3.27 by adding HCl, the viscosity of the transparent solutions with wormlike micelles was increased rapidly and reached ∼3100 mPa s. Furthermore, on increasing the pH by adding NaOH, the viscosity was slightly increased due to the addition of Na + . However, the increase in the concentration of Na + is much smaller than the theoretical addition. The same phenomenon was noted in the sodium citrate solution, but does not exist in the sodium formate system. The viscosity of the micellar solution has a sensitive response to inorganic acids and tolerance to inorganic bases due to the characteristics of polybasic acids.