Advancement in surfactant-enhanced droplet deposition on the hydrophobic surfaces

Droplets impacting solid surfaces are encountered in nature and industry, from rain to agricultural spraying and inkjet printing. Surfactants are an important factor that affects the impact behavior of droplets. An in-depth knowledge of the influence and mechanisms of surfactants on the dynamics of droplet impact can enhance the precise control of droplets in industrial processes. Herein, recent insights into surfactant-enhanced droplet deposition on hydrophobic surfaces are reviewed. First, the mechanisms of surfactant-enhanced droplet deposition are summarized. Second, the factors that influence droplet deposition, such as molecular diffusion, convective diffusion of surfactants, characteristics of hydrophobic surfaces, and interaction between the surfactant-laden droplets and the hydrophobic surfaces, are explored. Additionally, the influences of surfactants on the spreading and retraction processes of impacting droplets, maximum spreading factor, and oscillation dynamics are reviewed. Finally, typical applications of surfactants in different fields, such as inkjet printing, supercooled surface, and agricultural spray, are summarized, along with challenges and prospects in future research, to provide suggestions for subsequent studies.