GTIIT Soft Matter and Biological Physics Seminar (GTIIT BioSoft Seminar)

Title: The drying of liquid droplets

Speaker: Prof. Xingkun Man (Beihang University)

Date: Tuesday, Nov. 28th, 2017

Time: 14:00-14:45 (Light refreshments will be served afterwards.)

Venue: Rm E211, Education building, GTIIT

Abstract:

The drying of liquid droplets is a common daily life phenomenon that has long held a special interest in scientific research. We propose an Onsager variational principle theory that describes the droplet shape evolution and predicts the deposit distribution of nonvolatile components on the substrate. It is shown that for the drying of a single droplet, the deposition pattern changes continuously from a coffee ring to volcanolike and to mountainlike depending on the mobility of the contact line and the evaporation rate. When drying of two neighboring droplets, asymmetrical ring-like deposition patterns are formed, including fanlike and eclipse-like deposition patterns. The same theoretical model also explained the observed attraction-repulsion-chasing behaviors of evaporating droplets, where the droplets are not pinned. Evaporating droplets are known to show complex motion that has conventionally been explained by the Marangoni effect (flow induced by the gradient of surface tension). We show that the droplet motion can be induced even in the absence of the Marangoni effect due to the gradient of evaporation rate.

All the faculties and students are welcome!