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Electroactive Polymers that expand under low voltages

  1. Oct 3, 2016 #1
    Hello internet!

    I understand the basic principle of EAPs (you apply a potential difference and it moves) but I can't for the life of me find any specific, named EAPs that fit my requirements. If possible could you tell me if you know of an EAP that:

    Works in a normal environment (air, room temperature, etc...)
    Doesn't cost the earth
    Expands (if only by a little bit, say 10%) under a relatively low voltage (that is safe for people).

    To help you envisage what I'm after imagine a tube that normally has a small diameter, but when a low, safe voltage is applied, expands slightly to have a larger diameter. It would be a bit like reusable heat shrink; apply voltage to make it expand, put it over a bunch of wires for example, remove the voltage and watch as it shrinks tightly over the wires. Then, if you decide it is in the wrong place, you can simply re-apply the voltage, causing it to expand again and allowing you to remove it.

    Thanks for any insight you can offer!
  2. jcsd
  3. Oct 3, 2016 #2


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    Science Advisor

    The problem you will have is that the polymer contracts by a couple of percent when voltage is applied. Unfortunately, when the voltage is removed the polymer expands again and so would be free to slide. That is the opposite of what you want.

    Heat-shrink insulation can shrink by about 40%. Cable ties can get better than 95% contraction, some are even reversible.
  4. Oct 4, 2016 #3
    I was thinking more along the lines of the 'resting state' (no voltage) being tight, and then expanding when you need it to (by applying a voltage). I am under the impression that you can get EAPs that expand when a voltage is applied, as well as EAPs that contract when a voltage is applied. Is this correct?
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