Diodes Could Drive Swimming Micro-Robots

finisterre writes "Diodes can be made to 'swim' through salt water by hitting them with an alternating electric field. The applied field induces a current that sets up a field between the diode's electrical contacts and creates a propulsive force. The abstract of the paper in Nature Materials is freely available. New Scientist has videos of the swimming diodes in action."

Comments

Voltage?

[AmIAnAi]

Anyone know what voltage was used here. Personally, I don't fancy being hooked up to the AC to drive nano-scale surgical robots round my body.

Toy + Publicity Stunt

[Bender_]

That is all there is. The propulsion principle has been known for at least a hundred years. The only 'new' thing is to use a diode to generate a DC field from externally applied AC. But actually that does not really solve any practical problem.

Re:and what is the application?

[ArsenneLupin]

I see not a single practical application mentioned with adecent justification for that application being superior or equivalent to some other method. Actually, they did mention one application: medical microrobots. And they mentioned why their method might be superior to other methods (such as a micromotor driving a ship-screw):

But extrapolations of the team's measurements indicate the propulsive force will work just as well at smaller scales. "The propulsive force scales in exactly the same way as the drag. That's quite significant," says McKinley.

==> drag would be a problem for other methods, but not for this one.

Re:Reading this before properly waking up...

[MightyYar]

You need to re-read that article. It simply states that coffee drinkers are no more alert than non-coffee drinkers; it does not say that regular coffee drinkers are just as alert before and after their first cup of coffee. In fact, it explains why regular coffee drinkers need the morning cup to come back up to a baseline of normal alertness.