What In the World is SONOCHEMISTRY?

 

    May I interest you in a 1 millimeter bubble with the heat of the surface of our sun and 100 MPa of pressure? Too bad, because that’s what I’m blogging about today, and it’s not as far out as it may sound. Sonochemistry is today’s topic, and I’ll tell you right now that I’m nerding out on this so hard I can feel it in my bones. Well, I also just brushed my teeth with my ultrasonic toothbrush which would explain feeling it in my bones, but I digress. Point being, I think ultrasonic stuff is super cool and I’ve daydreamed about its potential for over half my life, so reading this compendium of research in ultrasonic technology is immensely exciting to me. Hopefully some of that excitement will rub off on you as well.  

    The article I’m reviewing today is entitled Sonochemistry: Science and Engineering and was written by Nimesh Pokhrel, Phani Kiran Vabbina, and Nezih Pala for the journal Ultrasonics Sonochemistry in 2016. Here’s the DOI, and I implore you to read the article in full since there I’m only covering the tip of the iceberg: https://doi.org/10.1016/j.ultsonch.2015.07.023 

    But let’s start from the top: what is sonochemistry?  Sonochemistry is the utilization of ultrasonic waves to cause, alter, assist or enhance chemical reactions. This article addresses sonochemistry specifically in regards to nanomaterials. “Reducing the size of a material to nanoscale confines the electrons (and photons) inside to limited movement that brings changes to its physical and chemical property.” (Pokhrel et al., 2016) And, yes, use of ultrasound can produce 1 millimeter bubbles over 5000 degrees Kelvin (around as hot as the surface of the sun) with 100 MPa of pressure, while also producing sonoluminescence (light) as well as “high-energy particle collision which generates energy as high as 12 eV,” but only for about one trillionth of a second. If that wasn’t impressive enough, there have been instances where formation of plasma inside of the bubbles has occurred, as well as evidence of nuclear fusion. Not only that, but it does so in a very cost effective manner which opens doors for experimentation across various fields that isn’t possible by more “traditional” means of altering chemical reactions.

    The introduction of ultrasound results in conditions that manipulate the physical and chemical structure of materials at the atomic level. The type of liquid chemicals make a big difference in the cavitation process, which is the formation of vapor bubbles through the high velocity movement of the ultrasonic waves, and researchers are still only skimming the tip of the iceberg when it comes to fully customizing combinations of ultrasonic frequency with liquid chemical solutions as a substrate for producing and controlling ultrasonic bubbles that can modify the very crystalline structure of materials. “The significance of sonochemistry, as a result, lies in its primary form where energy and matter interact in a flowing condition to produce extraordinary materials.” (Pokhrel et al. , 2016)  You hear[/see] that? EXTRAORDINARY MATERIALS!

Let me recap this: Sonochemistry is the use of acoustics (ultrasound) in various chemical solutions that cause bubbles to form (cavitation) which produce so much energy in such a short amount of time (a trillionth of a second per bubble) that materials submerged in the solution can be manipulated on the atomic level, altering the very crystalline structure of the material, resulting in the formation of, say it with me, extraordinary materials. 

Serious nerdgasm right there, and this only covers the very, very basics of this article. I mean, come on- light from sound? Nuclear fusion in an easily measurable scale? Plasma in a bubble? All through sound waves in chemical solution, which, is simply water in some cases.

    I could spend the next 3 days writing a review of this article after spending 3 weeks reading and analyzing the content and all of the references it is derived from, if only I had the time. It’s hard enough to not constantly quote from it because there’s not a whole lot of ways to phrase their findings any better than the authors already have. Very well written.

I’m going to conclude this article with a block quote from the last article of the conclusion as one last attempt at persuading you to read the whole article yourself. It is truly fascinating and is about 24 pages worth of content. 

“The opportunities sonochemistry sets up are as exciting as the process, and are imminently realizable. Understanding the mutual effect of input parameters can not only assure control over nanomaterial growth, but also help grow specific materials and unlock new applications. Sonochemically synthesized catalytic metal nanoparticles used in purification, can be furthered to autonomously rectify waste and pollution. Precise drug delivery with the help of sonochemically synthesized protein microcapsules has shown encouraging result in case of tumor treatment, and with the active ongoing research can soon be applicable for other medical conditions. Similarly, the facile sonochemical processing of graphene, carbon nanotubes etc. can help achieve the immense potential these materials promise if performed in large scale. Sonochemistry reaches out even farther for its ability to use different substrates to grow such expedient materials. ZnO nanoparticles synthesized sonochemically on paper and fabrics such as cotton and nylon forecast the advancing smart textile industry. The effective antimicrobial property of ZnO and its UV screening, given its biocompatibility, will not only help improve our health standard but also the textiles we use in daily basis. Given the opportunity, our group is working dedicatedly towards making wearable, portable and real-time biosensor that enables constant monitoring of a person’s health. With sonochemistry, possibilities lay endlessly for aspiring researchers.”

Works Cited

Pokhrel, Nimesh, et al. “Sonochemistry: Science and Engineering.” Ultrasonics Sonochemistry, vol. 29, 16 Mar. 2016, pp. 104–128., https://doi.org/10.1016/j.ultsonch.2015.07.023.