ETH scientists have developed cube-shaped magnetic building blocks that can be assembled into two-dimensional shapes and controlled by an external magnetic field. They can be used for soft robotics applications.
If you’ve ever tried to put several really strong, small cube magnets right next to each other on a magnetic board, you’ll know that you just can’t do it. What happens is that the magnets always arrange themselves in a column sticking out vertically from the magnetic board. Moreover, it’s almost impossible to join several rows of these magnets together to form a flat surface. That’s because magnets are dipolar. Equal poles repel each other, with the north pole of one magnet always attaching itself to the south pole of another and vice versa. This explains why they form a column with all the magnets aligned the same way.
Now, scientists at ETH Zurich have managed to create magnetic building blocks in the shape of cubes that – for the first time ever – can be joined together to form two-dimensional shapes. The new building blocks, which the scientists call modules, are not dipolar but quadrupolar, which means they each have two north poles and two south poles. Inside each of the modules, which are 3D printed in plastic, there are two small conventional dipole magnets with their equal poles facing each other (see picture). The building blocks can be assembled like little chess boards to form any two-dimensional shapes. It works like this: Because the south and north poles attract each other, a quadrupole building block with its two south poles facing left and right will attract, on each of its four sides, a building block that is rotated by 90 degrees so its north poles on face left and right.
Source: “Magnets for the second dimension”, Zurich ETH News