Pineda, F., Angel, A., Palay, F. E., & Rosenkranz, A. (2025). Elucidating the Role of Surfactants and Dispersants in Tailoring the Aqueous Behavior of Multi-layer Ti₃C₂Tₓ. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 138820. https://doi.org/10.1016/j.colsurfa.2025.138820

Abstract: The aqueous colloidal stability of multilayer Ti₃C₂Tₓ MXene is essencial for coatings, printed electronics, and nanofluids. We benchmark cetyltrimethylammonium bromide (CTAB, cationic), sodium dodecyl sulfate (SDS, anionic), and triethylamine (TEA, dispersant) across concentration windows referenced to CMC (surfactants) or wt.-% (TEA) using UV-Vis spectroscopy, dynamic light scattering (DLS), and zeta potential within a short-term (<30 min) post-sonication window. Ionic surfactants near their CMC greatly enhanced the colloidal stability in water, with CTAB and SDS showing complementary optima (higher supernatant concentration and smaller Dh for CTAB; larger |ζ| for SDS). TEA yields moderate improvements attributed to a pH-induced deprotonation of surface groups and the resulting increase in negative surface charge, while no direct evidence of oxidation suppression or surface passivation was obtained. Our results provide a controlled baseline contrasting micelle-mediated (CTAB/SDS) and pH-driven (TEA) routes for short-term stabilization and outline logical next steps, long-term stability, temperature effects, and device-relevant operation to enable a practical MXene processing.