Reversible Performance of Dodecyl Tetramethyl Guanidine Solution Induced by CO₂ Trigger

Abstract Dodecyl tetramethyl guanidine (DTMG) were synthesized and characterized, and its reversible performance was studied. The results showed that DTMG could form bicarbonate ionic adduct after exposed to CO 2 , so it could be used as CO 2 switchable surfactants. By bubbling CO 2 through DTMG solution or heating CO 2 saturated DTMG solution, the alkali and surface active properties of solution was changed reversibly. Emulsion and foam stabilized by DTMG could be controlled between stable and unstable state by CO 2 . In addition, the state of DTMG solution was easy to be distinguished by naked eye through a simple indicator, phenolphthalein. Pink indicated it was inactive, and colorless indicated it was active.