Engineering Commons^™

Pattern Formation During The Evaporation Of A Colloidal Nanoliter Drop: A Numerical And Experimental Study, Rajneesh Bhardwaj, Xiaohua Fang, Daniel Attinger

Daniel Attinger

An efficient way to precisely pattern particles on solid surfaces is to dispense and evaporate colloidal drops, as for bioassays. The dried deposits often exhibit complex structures exemplified by the coffee ring pattern, where most particles have accumulated at the periphery of the deposit. In this work, the formation of deposits during the drying of nanoliter colloidal drops on a flat substrate is investigated numerically and experimentally. A finite-element numerical model is developed that solves the Navier–Stokes, heat and mass transport equations in a Lagrangian framework. The diffusion of vapor in the atmosphere is solved numerically, providing an exact boundary …