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How would you go about making a sonosensitizer

  1. Nov 18, 2013 #1
    How would you go about making a "sonosensitizer"

    I'm fascinated by this sonoluminescence phenomenon, and how it could apply to photosensitizers, so as a mental exercise (which I may test out in the lab since if I have the opportunity), I'm thinking of how one would come up with a molecule which can exploit the sonoluminescence effect produced by ultrasound irradiation. From what I've read, its not known what causes this ultrasound induced sonoluminescence phenomenon but the main theory I read is that ultrasound causes the implosion of air bubbles in the solvent which induces extremely high temperatures, and the emission of photons. So I'll assume this theory is valid. In this case, the quantum yield of the sonosensitizer would be directly proportional to the amount of these air bubbles present in the solvent. Thats not necessarily something that can be controlled in practical applications, so another factor would be the proximity of the air bubble to the photosensitizer molecule.

    Is there a type of molecule that can surround air bubbles, similar to how surfactant molecules in an aqueous solvent organise themselves around the insoluble organic solvents in a spherical fashion? With porphyrin like dyes, all kinds of side chains like crown ethers can be conjugated to the photophore, but I don't know of any groups which would attract undissolved gas bubbles like that.
    Last edited: Nov 18, 2013
  2. jcsd
  3. Nov 20, 2013 #2
    A couple thoughts:
    It seems like you want a colloid where the stabilized phase is a gas, like a foam but with more liquid than gas.
    If you want to stabilize the gas bubbles in the solvent, density is a concern. If the bubbles simply rise/float to the top of the liquid, they are not stable.
    Does the gas have to be air? What are the effects if you choose a reactive gas (O2 or F) vs an inert gas (He or Ne)? Can you choose a gas molecule that will react with the sensitizer molecules but not the solvent? How big do the bubbles need to be to create enough energy for photoemission? You could look at cucurbiturils http://en.wikipedia.org/wiki/Cucurbituril which have sub-nm scale cavities.

    If you simply want to induce more sonoluminescence, could you simply introduce more gas bubbles into a solvent during ultrasonication? I.e., bubble nitrogen under a filter with submicron pores to induce small bubble formation.
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