Control of the particle deposition in inkjet-printed droplets

Abstract

Radial flow in drying droplets forms a ring stain deposit. By controlling the amount of radial flow using an evaporation-driven sol–gel transition in laponite suspensions, a uniform deposit can be achieved. Droplets gel from the contact line inwards, reducing particle flow to the droplet periphery. The method is demonstrated for picolitre droplets relevant to inkjet printing. Internal flows are visualized using high-speed imaging techniques. The final deposits are characterized by scanning electron microscopy and white light interferometry.