Colloidal stability of 2D MoS2 obtained via liquid-phase exfoliation using Water and Tween 20

• Environmentally friendly aqueous exfoliation of MoS 2 using a nonionic surfactant. • High shear mixing yields stable MoS 2 dispersions with tunable flake size. • Sedimentation kinetics and AFM confirm progressive exfoliation upon longer mixing. • Simple and scalable route suitable for further processing and applications. We report a facile and potentially scalable aqueous liquid-phase exfoliation of MoS 2 using the nonionic surfactant Tween 20 and a conventional high-shear mixer. The influence of shear time on flake size, electrokinetic potential, and colloidal stability was systematically investigated. Increasing exfoliation time led to a reduction in apparent particle size and a shift of the electrokinetic potential toward more negative values, indicating improved dispersion stability The most exfoliated sample exhibited a sedimentation exponent (α ≈ 0.20), corresponding to slow sedimentation and enhanced colloidal stability. The concentration of dispersed material increased with shear time, reaching 0.017 mg mL -1 , with approximately 51% retention after 28 days. To the best of our knowledge, this study is the first to address liquid exfoliation of MoS 2 in water with the addition of the Tween 20. The approach is environmentally benign, inexpensive and yields stable aqueous MoS 2 dispersions suitable for further processing and application.