Drying Process of Micro-Scale Polymer Solution Droplets Deposited on Lyophobic Surfaces

Abstract

A micro-scale polymer solution droplet is deposited on a lyophobic surface using an inkjet printing method, and then dried to form a thin polymer film. The shapes of the films formed from xylene-polystyrene (PS) droplets are changed from ring-like to dot-like as the initial PS concentration decreases. Detailed investigations of the drying processes reveal that the pinning time of the contact line dominates the shape and dimension of the polymer film. For ethyl acetate/acetophenone-PS solutions, ethyl acetate rapidly evaporates at the initial stage, but it plays an important role in delaying the pinning time. As a result, this binary solvent forms a dot-like polymer film.