Ferrofluids — those mesmerizing drops of magnetic liquid — can perform a number of neat tricks under certain conditions. But what would happen if you placed a blob of the stuff on a hydrophobic surface? Watch these videos to find out.


You've probably seen ferrofluids in action before.


But for this experiment, which was conducted by researchers from Aalto University and Paris Tech, drops of the magnetic liquid were placed on a water repellent surface. This caused them to align in a number of interesting patterns and orientations when subjected to periodically oscillating magnetic fields.

Here, you can see the splitting effect as the magnetic strength is increased:

The magnet is gradually lifted, which increases the magnetic field on the droplet. Eventually, it deforms to the point where it splits into two daughter droplets.


And in this video, a computer-controlled linear actuator puts the magnet into sinusoidal motion with different frequencies and amplitudes:

This is what the researchers refer to as reversible switching between static and dynamic self-assembly (defined as “a process in which interacting bodies are autonomously driven into ordered structures.”). Interestingly, these insights could open the way to the creation of new responsive and intelligent systems and materials — including, possibly, liquid self-assembly T-1000 style.


Read the entire study at Science: “Switchable Static and Dynamic Self-Assembly of Magnetic Droplets on Superhydrophobic Surfaces.”

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