"Janus particles" simultaneously enable drive and function
Especially interesting for the group are the so-called Janus particles. Like a Janus head, these have two different sides: One is coated with a catalytically active layer, the other remains untreated. The drive works as follows: When light falls onto the catalytically active side, the coating is subjected to energetic excitation. This triggers chemical reactions with molecules from the liquid on the surface of the particle. Finally, the newly formed molecules accumulate in the water on the coated side of the Janus particle. This slowly leads to a difference in concentration between the two sides of the Janus particle – a so-called gradient. And this gradient causes the particle to start moving by itself, a phenomenon known as self-diffusiophoresis.
New "fuels" for the movement in the micro world
Juliane Simmchen wants to gain a detailed understanding of such processes in order to develop new "fuels" and better control over this movement. She works together with physicists from other research institutions who simulate the processes on the computer.
Actually, our work has a lot to do with tinkering around
For all the theory, our chemist has clear applications in mind: It is conceivable, for instance, that such particles could be used to specifically target and fish out pollutants from a liquid and transport them away. And it is possible that in the future other particles might be used to direct drugs through the body to a tumor.