Peculiar surface profile of poly(ethylene oxide) film with ring-like nucleation distribution induced by Marangoni flow effect

Marangoni convection is the dominant flow when the substrate temperature is above 60°C, and the peculiar ‘dual-ring’ profile of the PEO film contains ring-like profile at the edge and volcano-like profile in the middle. A ring-like nucleation distribution shows that the memory effect of polymer crystallization behavior on flow field could provide a visual mark for Marangoni convection, and lamellar vortex structure in the spherulite center further confirms this conclusion. Marangoni convection is the dominant flow in the later high temperature drying stage, and results in peculiar ‘dual-ring’ profile and special ring-like nucleation of the deposited PEO film.