Speaker
Description
When a droplet interacts with a soft surface, it can deform the material it contacts. This property leads to a plethora of unique physical phenomena with applications in fields ranging from water collection to surface sensing. We explore droplet dynamics on soft materials using a micropipette-based technique to simultaneously image, and measure the forces on, a microscopic droplet dragged along the surface of a soft elastomeric polydimethylsiloxane (PDMS) film. By changing the thickness of the elastomer film, we can control the compliance of the substrate independent of surface chemistry. We are also able to control and measure the presence of uncrosslinked PDMS chains in our system. We model the dynamics of the droplet-substrate interaction and expect dissipation to scale with the size of the capillary deformation. We find agreement between our model and experimental results.
