Vesicle aggregation based on hydrophobic interactions

• Published in: Colloid and polymer science 2015-12, Vol.293 (12), p.3633-3639
• Main Authors: Zhao, Jian-xi, Liu, Fen, Xie, Dan-hua
• Format: Article
• Language: English
• Subjects: Agglomeration; Cationic; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Complex Fluids and Microfluidics; Food Science; Hydrophobicity; Nanotechnology and Microengineering; Original Contribution; Physical Chemistry; Polymer Sciences; Soft and Granular Matter; Spacers; Surfactants; Transmission electron microscopy; Turbidity; Vesicles
• ISSN: 0303-402X; 1435-1536
• DOI: 10.1007/s00396-015-3747-9

Vesicles were formed in aqueous mixtures of gemini anionic surfactant, O,O′-bis(sodium 2-alkylcarboxylate)- p -dibenzenediol (referred to as C m ϕ 2 C m , m  = 10, 12), and single-chain cationic surfactant, alkyltrimethylammonium bromides C n NBr ( n  = 8, 10, 12). This was confirmed by measurements of solution turbidity, dynamic light scattering (DLS) and freeze-fractured TEM. The improvement of the C m ϕ 2 C m molecular geometry by C n NBr was considered to have been due to vesicle formation. As the temperature was raised, these vesicles were found to associate together and DLS measurements showed a rapid increase of the aggregate size at the critical temperature T c . The mechanism of vesicle aggregation was assumed to be due to the temperature-induced configuration transition of a few C m ϕ 2 C m molecules in the vesicles from cis - into trans -form. Thus, a few tails of C m ϕ 2 C m stretched toward the solution. When the vesicles approached, these projecting tails interacted hydrophobically, thereby non-covalently attaching one vesicle to another. This should benefit from the special molecular structure of C m ϕ 2 C m with a long, rigid spacer.