Film-formation trend and film coverage percentage of continuous convective self-assembling of 2D colloidal crystals

The dynamics of polystyrene(PS) micro-spheres in thin layers of continuous convective self-assembly of 2D colloidal crystals was studied systemically. The mechanisms of void and stripe patterns were analyzed, based on the model of assembly. To explain the film-formation trend, a mathematical model including the coverage percentage of colloidal crystals, the substrate withdrawing velocity and the colloidal suspension concentration was derived. The result shows that higher particle volume fraction and lower substrate withdrawing velocity lead to larger coverage percentage of colloidal crystals. Void and multilayer flaws always appear in the self-assembled 2D colloidal crystals, and the monolayer coverage percentage can be 95%.