Endowing conventional hydrophobic associating polymer solution CO₂ stimuli-responsive property with a CO₂ switchable surfactant

Abstract

The performance of hydrophobic associating polymers could be significantly affected by addition of a small amount of surfactant, especially around the critical association concentration. In this work, a CO₂ stimuli responsive surfactant, N, N-dimethyl oleoaminde-propylamine (PKO), was introduced into the hydrophobic associating polymer solution (PMA), which endowed the conventional hydrophobic associating polymer solution with CO₂ stimuli responsive performance. The conductivity measurements indicated the molecular structure and properties of PKO could be regulated with bubbling and removal of CO₂ and the protonated surfactant exhibited superior surface activity. In the presence of CO₂, PKO interacted with hydrophobic monomer to be mixed micelles, which prompted the transition of PMA aggregation from intramolecular association to intermolecular association, exhibiting a gel-like fluid. With removal of CO₂, the mixed micelles were dissociated and the viscosity of the solution decreased significantly, leading a water-like fluid. The reversible transition of aggregation and performance could be regulated reversibly through the presence and removal of CO₂. The PMA-PKO systems with CO₂ switchable performance would have wide applications in hydraulic fracturing and oil production.

Graphical Abstract

Keywords:

• Hydrophobic associating polymer
• polymer-surfactant system
• CO₂ stimuli-responsive

Additional information

Funding

This work was supported by the Postdoctoral Science Foundation of China (No. 2018M631100).