A group researchers in MIT (Massachusetts Institute of Technology) recently developed an approach to use liquid droplets to connect two moving parts without any solid contacts. This is a breakthrough innovation which makes many things possible in the field of MEMS (Micorelectromechanical Systems). For those not familiar with MEMS, they are tiny machines developed for industrial uses in electronic industry such as the manufacturing of chips and such components. Being small machines wear and failure is a big issue. Since the connections between two moving parts are very tiny in these machines they tend to fail easily. By finding an alternative to such solid connections this industry is taking a big leap.
The principle used in this approach is common knowledge. We all know that certain surfaces tend to repel water while others attract. The water droplets on a water repelling or hydrophobic surface tend to stay together while those on a hydrophilic (water attracting) surface tend to spread evenly. So in the former case the height of aÂ water droplet will be much larger than a droplet in the latter case. By altering this water water repelling or attracting qualities we can make the water droplets move.
In the case of certain dielectric surfaces these above qualities can be altered by passing small amounts of electricity. Here basically you get a water droplet that change its height and width when you flip on a switch. While the concept is not new only the researchers in MIT had the mind to put it in for a practical application like moving a platform. They put a tiny platform on top of two water droplets and varied its height by regulating the electricity flow to the platform they are kept on. The same method can be used to move the droplets from one position to another or to tilt them. This simple experiment opens the doors to a new era of MEMS.
While avoiding wear and failure in MEMS machines are agreat advantage this experiment also proves to be a method to make highly precise movements. The initial experiments could control the platform with a precision of 10 microns. This has great scope in many industries were very precise movements are required, for example laser related experiments need very high precision movements.
Another advantage of this system is that it is relatively vibration resistant compared to solid connections. Given the simplicity of this experiment it wouldn’t be long before we see them in real world applications.
Source – Movable microplatform floats on a sea of droplets