Controlling Fluids and Particles with Active Surfaces
Dirty windows and glasses can be annoying and even dangerous in some situations, and in others, such as with solar panels, dirt can compromise efficiency. The only way to address the problem is to clean the surface, and researchers have been working on developing better ways to do this, possibly making it automatic. Now researchers at MIT and in Saudi Arabia have found a way to make a surface that grants control over what covers it, which could lead to advanced cleaning methods or new biomedical devices.
Typically surfaces are just a passive object that other things rest on, so getting those things off requires some external force. By putting a microtexture on the surface and a magnetic fluid in the bumps and ridges, the researchers have made it active. When something, like a water droplet or small particle falls on this surface, the magnetic fluid made of oil and magnetic particle, will actually coat it, and being magnetic, enables a magnetic field to manipulate the droplet. As the surface is also low friction, the droplet is easily moved by an external field, unlike in other experiments which required powerful magnets to work.
Potentially this technology could be used to quickly clean off solar panels with less labor and less water, which is very important for solar panels in desert environments. We could also see active-surface systems being used to manipulate biological fluids, which are usually difficult to manipulate.