Wikipedia, the keeper of all modern knowledge in modern day America, tells us: Water-absorbing polymers, which are classified as hydrogels when cross-linked, absorb aqueous solutions through hydrogen bonding with water molecules. A SAP’s ability to absorb water depends on the ionic concentration of the aqueous solution. In deionized and distilled water, a SAP may absorb 300 times its weight (from 30 to 60 times its own volume) and can become up to 99.9% liquid, but when put into a 0.9% saline solution, the absorbency drops to approximately 50 times its weight. The presence of valence cations in the solution impedes the polymer’s ability to bond with the water molecule.
From my experience visiting Emerging Technologies, Inc, I can say that these are magical, salt-looking grains that turn liquid into non-liquid, make snow on-demand, and are being used to make life look better, feel better and, in some cases, likely saving lives.
During our interview with David Carter, for the maiden voyage of the Thank You Science podcast, we entered the world of super absorbent polymers (SAP, for short – and, not to be confused with the German software company). David founded Emerging Technologies, Inc twenty years ago and he and his team deliver SAPs daily to customers around the globe.
In every market, there are influencers. When it comes to SAPs, diapers are king. Most of the polymers that are created go to makers of personal hygiene products. Those companies keep a keen eye on which areas of the globe are experiencing booms in birth, aging, and gender population make-up. So, to a certain extent, the creators of SAPs also have to pay attention to geo- and demographic trends, as well. Not to let the vernacular get too science-y but there is quite a bit of time spent on how these polymers respond when a diaper is “insulted.”
But the uses for these materials are extremely varied, and the potential seems to be almost limitless – during our discussion with David Carter and super-chemist, Jeff Lichiello, the TYS team came up with many wonderfully stupid uses for ETIs products. (editor’s note: Curt came up with stupid ideas, while Ken and Hillary offered useful ones)
There is ground-breaking work being done today on ways to better use super absorbent polymers to more quickly and simply clean up oil spills, keep water away from areas prone to flooding, and use it to help arid regions with keeping more water in the ground for plant production. Research continues to push the boundaries of what is possible today, what we will see delivered in the near-future, and what uses might be discovered down the road.
But, everything in the field doesn’t have to be insults to diapers and oceans, and agriculture. The “novelty” market is growing exponentially, as filmmakers, artists, and entertainers learn how to use these materials. Jeff Lichiello performed a number of demonstrations in his lab, with one of the most interesting being how the same SAP reacts differently based on how liquid is introduced. If water was slowly introduced, it would be absorbed and a semi-transparent gel would be produced – like a wet sponge. However, if you rapidly poured water onto the polymer, magically, “snow” would begin to form, overflowing from the container within seconds. It not only looked like snow, but also felt pretty close to the real thing as well (not as cold, of course). This has become a standard use for movie and photography sets, allowing them to not worry about the “melt factor” as just a few sprays with a water bottle will give it new life and allow them to continue working. (editor’s note: We understand that the reaction was not actually “magic” even if Curt does not. Also, “melt factor” was a term he made up while writing this article.)
The creative uses are broad, especially when you can vary the size and add color to the material. Adding water can create white “snow,” colored “marbles,” or “ice” on demand.
Though there is likely a bit of exaggeration in the title of this article, it’s also fair to say that the work being done in this field has, and will continue to have, impact on human beings and how we interact with the world around us. Whether it is something as important as hygiene or keeping crops alive during drought, or as silly as creating snow for a photoshoot in Texas, the ways we use and interact with SAPs are likely to become more broad, interesting, fun, and important. And, for the work being done by scientists like David and Jeff, and organizations such as Emerging Technologies, we would like to say, “Thank you.”