Final Week-Best Results

Given some fears about my the properties of my particular azobenzene compound, we ordered a particular reagent to synthesize another azobenzene that will conserve all of the helpful properties of my current one, and allow it to recover faster. This should make my experiment much faster to run and overall more easily-applicable in the future.

With that decided, and not much left to do, I figured that I’d make some nanoparticles, doped with my current azobenzene and see how they worked in an all-water environment. By incorporating the nanos, which are fluorescent, it gave me an opportunity to use the fluorimeter, which is more useful at observing the inner workings of the nanos. Surprisingly, they worked incredibly well. I didn’t have an opportunity to run a pH test, but I used the highest possible intensity of light and photobleaching was almost non-existent.  I achieved much cleaner and useful results than I had in the Fall, and it restored my faith that it’s possible my recent azo compound will work as well.

The one concern is that the fluroescence spectrum of the undoped PPE nanoparticles does not match literature, or the spectrum we observed in the Fall, and I’m worried it may have decomposed or undergone some sort of other reaction. It makes the results slightly less promising, but we have ordered a new batch of PPE and hopefully future testing with that sample will confirm my results from this week.


  1. Congratulations from your fellow labling! I think you made the right move by testing your azobenzene in a nanoparticle environment. It is after all the environment that we are most interested in. About the fluorescence spectrum that looks different, you might want to try running parallel experiments on UV-Vis and fluorimeter so that you can have a better idea about the identity of the molecules as well as their relative amount. From there the energy processes that you’re interested in can be observed, and confirmed, with more credibility.

  2. That was such a breakthrough! After repeatedly not obtaining the expected results, it can be very hard to push on. I am glad you kept trying and stumbled upon some great results!

  3. I ended up here when i was searching for information on PAGs ability to breakdown in water. You seem like someone that might know the answer to this.
    I am new to the world of PAG and I have been trying to figure out if they breakdown when exposed to water or not. I am told that some are tight ion pairs and they wouldn’t breakdown at all but from your results and some lit, it looks like they do breakdown when they go into water, particularly in a natural environment. I know that UV would only speed up this breakdown but how can I figure out if a PAG I have is likely to breakdown in water?
    If you can give me any info on this and maybe point me in the right direction to find out more info it would be awesome. Thanks and keep up the great work.

  4. Aaron Bayles says:

    Thanks for the question! I only work with this particular azobenzene derivative that also happens to be a PAG. There is a huge variety of PAGs and I’d say that their properties in water vary widely. My PAG is insoluble and generally unreactive in water when it’s by itself, but because I bond it to the hydrophilic nanoparticle, it can dissolve and become reactive. Therefore, I’d say you just need to keep an eye out for PAGs that are soluble in water, or can be made soluble.
    Not sure what you mean by “breakdown”. Are you referring to the release of acid? It’s very dependent on the individual molecule. One piece of literature that I reference is “2-Hydroxyazobenzenes to Tailor pH Pulses and Oscillations with Light” but I’m not sure of what other resources I have that could help you.