Nanoparticles do not influence droplet break-up, spreading, or splashing

The dynamics of nanoparticle-laden droplets, from dripping to impact, have remained a subject of intense debate due to conflicting reports in the literature. Here, we address this controversy by systematically investigating the breakup, impact, spreading, and splashing behavior of fully characterized additive-free silica nanosuspensions synthesized via the Stöber process. In the absence of additives, we find that nanoparticles exert negligible influence on the fluid viscosity and dynamic behavior of droplets during break up, spreading, and splashing - even in suspensions with a high loading concentration (15 wt.%). This work highlights the pivotal role of additives, dispersants, and interparticle interactions in governing droplet behavior. Our findings offer crucial insights for a wide range of fields, including inkjet printing and spray coating.