Effect of External Flow on Self-Assembly of Colloidal Suspensions Ying Sun, Department of Mechanical Engineering and Mechanics, Drexel University, Philadelphia, PA 19104 Ink jetting process: Three physical stages involved in inkjet printing of colloidal drops are shown below. Our focus is on the last stage that ultimately determines the deposition morphology. A schematic of our experimental setup is shown on the right. 1 - Drop Formation 2 – Impact and Spreading 3 – Evaporation & Self-assembly We seek to eliminate the “coffee stain” effect of inkjet-deposited colloidal drops for achieving uniform deposition through the optimization of ink and substrate properties, as well as process conditions.