Sciencemadness Discussion Board

Phase-changing substance: please help me out

tkdpainkiller - 10-7-2006 at 09:38

I am trying to find a substance whose state I can control using either UV light or electicity. Preferrably, it would be solid at room temperature, but exposure to some sort of stimulus would cause it to change into a "semisolid" or liquid with high viscosity. As I am not very knowledgeable in chemistry, there's no way I can find this on my own. Do you know of such a substance (preferrably one that can be handled safely)?

Also, do you know of a substance whose adhesiveness I can control?

Thanks,
Nick

[Edited on 10-7-2006 by tkdpainkiller]

neutrino - 10-7-2006 at 13:43

There are materials that go from liquid to semi-solid when subject to an electric field. Those are called electrorheological fluids. We have a thread on those here.

You might also want to consider ferrofluid. This liquid turns to a semi-solid when subject to a magnetic field. It's readily available from many scientific suppliers.

I don't know of any materials that reversibly change phases when UV light is added.

tkdpainkiller - 11-7-2006 at 08:20

This may be more of an engineering question....but I'm trying to use a device containing a fluid like this to pick up objects. A thin-walled bag containing the fluid, I'm thinking, could be "dropped" over the object and would conform to it. Then, a stimulus would be applied and the fluid would harden around the object.

Do you think this is reasonable? Also, would a ferrofluid be "strong" enough to pick up light objects?

franklyn - 11-7-2006 at 18:26

If anything your approach is original, but what is wrong with a part grabber or
clawed grabber tool. These have 3 , 4 , or 5 claws , and come in all sizes for
handling very small items like miniature machine screws up to ones suited to
getting that item you dropped behind the stove. These are often found in the
tool section of .99 cent stores.
The only appliction I know of like what you suggest is when as a kid we would
recover coins and change from under the sidewalk subway grates using a
weight on a string with a wad of chewing gum on the end. Works pretty good.

I think a ferro fliud as suggested is the only thing that may serve your purpose
but you're in new territory and on your own .

http://www.ehobbytools.com/index.html?target=p_22.html&l...

http://cgi.ebay.com/Flexible-Spring-Grabber-Claw-Pick-Up-Too...

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