Annular and threadlike wormlike micelles formed by a bio-based surfactant containing an extremely large hydrophobic group. Issue 4 (5th January 2018)

• Record Type: Journal Article
• Authors: Zhai, Zhaolan; Yan, Xinyan; Song, Zhanqian; Shang, Shibin; Rao, Xiaoping
• Is Part Of: Soft matter. Volume 14:Issue 4(2017)
• Page Start: 499
• Page End: 507
• Publication Date: 2018-01-05
• Subjects: Soft condensed matter -- Periodicals; 530.413
• DOI: 10.1039/c7sm02163a
• Languages: English
• ISSNs: 1744-683X

Abstract

Abstract : The overlap of an alkyl chain and a rigid group in C12 -MPA-Na promotes the formation of large spherical micelles and annular and threadlike micelles. Abstract : A novel bio-based anionic surfactant containing a large rigid group and a flexible alkyl chain, namely, sodium N -dodecyl-maleimidepimaric carboxylate (C12 -MPA-Na), was synthesized from rosin. The molecular structure of C12 -MPA-Na was identified using 1 H NMR, FT-IR spectroscopy and MS. Despite containing 36 carbon atoms, C12 -MPA-Na showed good water solubility at room temperature. Large spherical aggregates with diameters of 100–200 nm were formed by C12 -MPA-Na when its concentration was above 0.1 mM, which was slightly higher than the critical micelle concentration (0.078 mM). Annular wormlike micelles were discovered with increasing C12 -MPA-Na concentration, and began to change into extremely long threadlike wormlike micelles when the C12 -MPA-Na concentration reached approximately 58 mM. The viscoelastic properties of the wormlike micelle solutions were investigated using steady state and oscillatory shear sweep rheological measurements. The zero-shear viscosity ( η 0 ) strongly depended on the concentration of C12 -MPA-Na, and the scaling exponent was 34.1. Cryo-TEM confirmed the formation of large spherical aggregates and wormlike micelles. 1 H– 1 H 2D nuclear Overhauser effect spectroscopy (NOESY) was used to detect the molecular interactions of C12 -MPA-Na. The results indicated that the alkyl chain of C12 -MPA-Na was partially overlapped with its non-planar rigid structure in aqueous solution, and the possible aggregation process for C12 -MPA-Na was proposed.