Electroactive Polymers that expand under low voltages

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In summary, the conversation discusses the concept of EAPs (electroactive polymers) and the speaker's search for a specific type of EAP that meets certain requirements. They are looking for an EAP that works in a normal environment, is affordable, and can expand under a safe voltage. The speaker compares the desired EAP to reusable heat shrink and asks for any insight on potential options. The other person responds by mentioning that most EAPs contract when voltage is applied, which is not suitable for the speaker's needs. The conversation then mentions other materials, such as heat-shrink insulation and cable ties, that have high contraction capabilities but may not be reversible. The speaker clarifies that they are looking for an EAP that
  • #1
Pogona
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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!
 
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  • #2
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.
 
  • #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?
 

1. What are electroactive polymers (EAPs)?

Electroactive polymers (EAPs) are a type of material that can change shape, size, or other physical properties in response to an electrical stimulus. They are also known as artificial muscles or smart materials.

2. How do EAPs expand under low voltages?

EAPs expand under low voltages due to a phenomenon called electrostriction, where an applied electric field causes a change in the material's dimensions. This effect is caused by the movement of ions or dipoles within the material.

3. What are the potential applications of EAPs?

EAPs have a wide range of potential applications in fields such as robotics, biomedical engineering, and actuators. They can be used as artificial muscles, sensors, and energy harvesters due to their ability to convert electrical energy into mechanical energy.

4. Are there any limitations to using EAPs?

Yes, there are limitations to using EAPs. They typically require a high voltage to achieve large deformations, which can limit their practical use. They are also susceptible to degradation over time and may require a protective coating to improve their durability.

5. How are EAPs different from traditional materials?

EAPs are different from traditional materials in that they have the ability to change shape or properties in response to an electrical stimulus, whereas traditional materials do not. EAPs also have the potential to be more lightweight and energy-efficient compared to traditional materials.

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