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Piezo Nanofibers

  1. Dec 3, 2010 #1
    I am a Senior in high school and am currently working on a research team. We are currently doing research on nanofibers, specifically the creation of nanofibers with piezoelectric properties. One of our current obstacles is that we are unable to find the equations used to calculate piezoelectric charge. Can someone provide us with some help?

    P.S. I may have more questions as our research progresses.
  2. jcsd
  3. Dec 5, 2010 #2
    I am not sure what you mean? Ultimately, piezoelectric materials arise from the symmetry of a crystals point group, which is a property of its bonding.

    A piezoelectric material generates an electric field upon being stressed, or vice-a-versa. http://en.wikipedia.org/wiki/Piezoelectricity gives appropriate equations for stress and electric field generated. However, remember that the symmetry of the tensor is going to be dependent upon the symmetry of the crystal.

  4. Dec 6, 2010 #3
    I should probably mention that we have tried that wikipedia site but are having an extremely hard time deciphering the matrix. While I did not know about the importance of symmetry, I am actually running a couple of theories through my head for ways to solve that problem. But I digress. Is there any way someone could help by explaining what that matrix means in layman's terms?
  5. Dec 6, 2010 #4
    Well it's not every high school that gets itself into piezoelectricity. And it's probably possible to complete a physics degree without ever going very deep into this subject. Just how far are you in math? Have you seen Linear algebra? Calculus? Tensors? Solid state physics? What kind of research are you doing? Experimental? Literary? Theoretical? Need more input to be helpful.
  6. Dec 7, 2010 #5
    Ok. Here is a rough summary of our current state. If anyone has any more questions, please be specific. Most of us have experience in calculus, though I am still taking pre-calculus. Basically this is experimental research we are doing. Another thing I should probably mention is that we have an electrospinning lab set up so we can create nanofibers ourselves. There are a number of other teams working on different projects. We actually have a website set up if anyone is interested in finding out a bit more about our setup. The site is called http://thefutureisnear.org/index.html and gives a good perspective of what we do.

    While I am writing this, one of my team members just found out that one of the materials we were thinking of using will not work since it is insoluble in water. If anyone knows about a water soluble polymer we can use in our piezoelectricity experiments, I would be grateful.
  7. Dec 8, 2010 #6
    Piezoelectric crystals are well described in PRodQuanta's link. As for your fibers, the math will not any simpler.
  8. Dec 10, 2010 #7
    Ok. Quick update before I move on to the problem. First off, our teacher told us that the polymer actually will work since we have the equipment on hand. Didn't know that before. If anyone is currious as to what the polymer is, its Poly(vinylidene fluoride).

    The big problem right now is the matrix. The thing is, no matter what I try, I cannot figure out the matrix in PRodQuanta's link. I try to understand it but I can't. I haven't worked with matrixes for several years now and what I do know doesn't help me at all. I need someone to help me by explaining how exactly the matrix works.
  9. Dec 10, 2010 #8
    Regarding my last post, I appologise if I sounded rude or ungrateful or something. Its been along day at school and I'm kinda stressed. If I offended anyone, I appologise.
  10. Dec 14, 2010 #9
    Ok. Theres a new problem i need solved with this. After re-reading the matrix recomended by PRodQuanta, I just realized that that is for a piezo crystal. We aren't working with crystals, so the matrix is the wrong one for what we are working with.
  11. Dec 14, 2010 #10
    Yeah, that's why I say the the math will not be simpler. Crystals are the simplest solids to treat rigorously. To make any calculations about any other type of matter, you either have to make approximations, averages, or go at it empirically. I suggest you do a literary search, as this is not mainstream.
  12. Dec 18, 2010 #11
    I'm still not sure what exactly it is you are trying to do, but if you are trying to synthesize piezoelectric nanofibers, you must understand the mechanism for piezoelectricity. All piezoelectric materials' space group lacks a center of symmetry. So, if you try to synthesize a polycrystalline nanofibre that is piezoelectric, you must keep this in mind.
  13. Dec 23, 2010 #12
    But the thing is we are not trying to make a polycrystalline fiber. thats the problem.
  14. Dec 24, 2010 #13
    Maybe the math models haven't been developed yet for your mysterious fibers, you might have to look into it or develop it on your ownl! :tongue2:

    Seriously, I'm interested in piezoelectricity, but I haven't crossed much on fiber-based yet.

    To understand the basics, you'll need to learn classical EM, linear algebra, and solid state/condensed matter, all of which are included in the standard physics degree.
  15. Jan 5, 2011 #14
    Now I'm sorry if i sound rude with all these contradictions and arguments, but the thing is, its been done before. We have found documents from NASA saying that they have used these fibers in piezoelectrical experiments, they just dont tell us anything about where they got their formulas or calculations. Even the process they used to spin the fibers is pretty vague.
  16. Jan 5, 2011 #15
    I really haven't sensed any rudeness whatsoever :smile:, but it seems like you want to bypass standard piezo theory. Perhaps you can ask your teacher for help with this research.:wink:
  17. Jan 6, 2011 #16
    Well...that wont do any good. This is the first year that he has a group working on the topic and probably knows even less than my partners.:redface:
  18. Jan 10, 2011 #17
    Sorry for the topic change but the thing is we hit another road block. Can anyone explain how the poling process works?
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