Carbomer/arginine intelligent viscoelastic fluid with adjustable CO2-responsive viscosity

Abstract

Environmentally responsive intelligent viscoelastic fluids have been used in many fields in recent years. The rheological behavior of different intelligent viscoelastic fluids can be changed by different stimulation methods. Among them, CO2, as a non-toxic green and abundant stimulus method, has attracted much attention. Therefore, CO2-responsive intelligent viscoelastic fluids have been continuously reported, in which viscoelastic fluids with CO2-responsive viscosity increase have been more reported, while those with CO2-responsive viscosity decrease have been less reported. Herein, carbomer (CBM), as a pH-responsive polymer with potential CO2-responsiveness, is applied to CO2-responsive viscosity decreasing viscoelastic fluids. CBM and arginine (Arg) formed a new CO2-responsive viscoelastic fluid, which achieved a significant decrease in viscosity after CO2-response. Firstly, by comparing the effects of NaOH and Arg on the rheological behavior of CBM solution, it is demonstrated that Arg can extend the viscosity variation range of CBM solution before and after CO2-response, and Arg can switch between “physical crosslinking agent” and “viscosity reducing agent”, and it is verified from the microscopic perspective. Then, the effects of Arg concentration and CBM concentration on the CO2-responsiveness and rheological behavior of CBM/Arg viscoelastic fluid were investigated. The multiple reversible CO2-responsive viscosity of CBM/Arg viscoelastic fluid was verified. Finally, the viscoelastic variations of CBM/Arg viscoelastic fluid before and after the response were investigated by dynamic rheology.