Journal Article

Formulation, stability, and synergistic characteristics of diesel-in-water Pickering emulsions stabilized by titanium carbide (Ti3C2Tx) MXene and Tween 40

Johar, Aaminah, Abu Zaid, Nansee S.K., Nasser, Mustafa S., Mahmoud, Khaled A., Onaizi, Sagheer A.

2026

Overview

Enhanced oil recovery (EOR) operations increasingly depend on emulsion-based formulations that exhibit long-term stability under reservoir conditions while minimizing surfactant dosage. In this context, hybrid systems combining nanoparticles and surfactants offer a promising route to achieving both interfacial stability and formulation efficiency. Among potential nanoparticle candidates, Ti3C2Tx MXene exhibits high surface area and interfacial activity. However, its application in diesel-in-water Pickering emulsions under EOR-relevant conditions has not been explored. Challenges such as high hydrophilicity and strong electrostatic repulsion have limited the use of unmodified MXene as a standalone stabilizer in colloidal systems. To address this limitation, diesel-in-water Pickering emulsions were formulated using DL-Ti3C2Tx MXene combined with Tween 40 (0.5 wt%) and antifoam (0.15 wt%), aiming to investigate their synergistic stabilization behavior across MXene concentrations ranging from 0.1 to 1.5 wt%. The MXene-only system exhibited complete and immediate phase separation, whereas the hybrid emulsions demonstrated markedly enhanced stability, with no phase separation observed at 0.1 and 0.5 wt% after 24 h. A concentration-dependent trend was evident. At lower MXene contents, interfacial adsorption improved, and droplet sizes remained small and uniform. At higher concentrations (≥ 1.0 wt%), aggregation increased, and demulsification became more pronounced. Interfacial tension decreased steadily with increasing MXene content, reaching 0.86 mN/m at 1.5 wt%, while zeta potential remained strongly negative (−47.7 mV at 0.5 wt%), indicating sufficient electrostatic repulsion. Rheological analysis revealed a transition to shear-thinning behavior at higher MXene contents, confirming the formation of internal network structures. Compared to other reported systems based on silica (SiO2), zinc oxide (ZnO), or functionalized MXenes, the MXene-Tween 40 formulation achieved superior short- and long-term emulsion stability without requiring surface modification or external stimuli. To the best of our knowledge, this is the first study to report the successful stabilization of diesel-in-water Pickering emulsions using unmodified Ti3C2Tx MXene. These findings highlight the synergistic interaction between MXene and Tween 40 and present a robust, surfactant-lean formulation suitable for oilfield applications.

• Publisher: Elsevier B.V
• Subject: Emulsion rheology / Emulsion stability / Oil-in-water (O/W) Pickering emulsions / Pickering emulsion characteristics / Titanium carbide (Ti3C2Tx) MXene nanosheets / Tween 40 chemical surfactant