Preparation of CO₂ responsive wormlike micelles and the effect of hydrogen bond on the strength of the network

ABSTRACT

We first prepared two types of CO₂-responsive wormlike micelles based on N-butyldiethanolamine–sodium oleate (BDEA–NaOA) and N,N-diethyl butylamine–sodium oleate (DEBA–NaOA), respectively. And then, we compared the two different systems to investigate the effect of hydrogen bond on the properties of wormlike systems. The results of the pH and conductivity variation show that tertiary amine groups on BDEA and DEBA were ionized to quaternary ammonium salts after bubbling of CO₂ into the systems, which work with OA⁻ to form wormlike micelles based on electrostatic interaction. The results of rheological measurements exhibit that the viscosity and viscoelastic of the BDEA–NaOA were obviously superior to DEBA–NaOA. The dramatically difference of the two kind of wormlike micelles was due to the strong intermolecular hydrogen bond between the BDEA and NaOA. This indicates that the hydrogen bond could show great effect on the properties of the wormlike micelles. Finally, a reasonable mechanism was proposed based on the molecular structure, micelles assembly, and the intermolecular interactions.

GRAPHICAL ABSTRACT

KEYWORDS:

• CO₂ responsive
• hydrogen bond
• wormlike micelles