Our recent work on “coffee rings” was presented at the Gothenburg Science Festival, which, with about 100 000 visitors each year, is one of the largest popular science events in Europe.
On Wednesday 19th April 2023, Marcel Rey, Laura Natali, Daniela Pérez Guerrero and Caroline Adiels set up a stand in Nordstan.
In this guided exhibition, visitors were able to observe the flow inside a drying droplet using optical microscopes. They learned how the suspended solid coffee particles flow from the inside towards the edge of the coffee droplet, where they accumulate and cause the characteristic coffee ring pattern after drying.
Nowadays, the coffee ring effect presents still a major challenge in ink-jet printing or coating technologies, where a uniform drying is required. We thus shared our recently developed strategies to overcome the coffee ring effect and obtain a uniform deposit of drying droplets.
And finally, visitors were also offered a freshly-brewed espresso to not only drink but also to experience the “coffee ring effect” hands on.