Colloids with Reversible Stability Switched by Tris[2‐(dimethylamino)ethyl]amine

The addition of salt can irreversibly disrupt the stability of both emulsions and polymer latex. The reversible conversion of amines into organic ammonium salts can be induced by CO2 stimulation, thereby enabling the switching of colloids. The switchable amine, tris[2-(dimethylamino)ethyl]amine (Me(6)TRAN), was selected for the study. The electrical conductivity of an aqueous solution of Me(6)TRAN is modulated by the introduction and removal of CO2. The critical micelle concentration of sodium dodecyl benzene sulfonate (SDBS) was observed to decrease from 1.0 x 10(-3) to 5.0 x 10(-4) M upon the introduction of Me(6)TRAN, as confirmed by surface tension measurements conducted under CO2. The emulsion of crude oil, which comprised of SDBS and Me(6)TRAN, underwent reversible destruction and restoration upon exposure to CO2 and N-2. The PMMA latex exhibited a clear phase separation subsequent to CO2 sparging, but attained homogeneity upon N-2 sparging. This study is anticipated to introduce a novel avenue for emulsion or polymer latex that can undergo demulsification and emulsification through CO2 stimulation.