Welcome to Brainstuff from house stuff works dot com where smart happens. Hi Marshall Brain with today's question, how do polymer crystals work and why do they absorb so much water? If you have an infant or a toddler in diapers, you may occasionally notice these clear crystals sticking to his butt when you take the diaper off. These are called polymer crystals. Polymer crystals are one of those special things that are almost magical if you can watch them work.
Polymer crystals get very similar to a gelatin dessert when you put water on them. One of their major uses is indisposable diapers, where they're referred to as super absorbent polymers. This is the thing that allows a diaper to absorb lots and lots of urine without ever leaking. The polymers allow for thinner and lighter disposable diapers because they absorb so much water. Add water to the white crystal flakes,
and they absorb many many times their size. As the polymer gel forms, one pound of crystals holds about fifty gallons of water. The gel that forms swells by absorbing thirty grams of water for each gram of crystals construction workers, bicyclists, and motorcyclists can often be seen wearing cloth headbands or wearing a cloth collar around their neck. The crystals are sewn into a pouch in the cloth. The cloth item
is then soaked in water for several hours. That tiny handful will swell up too many times its size and provide moist evaporative cooling for the person who's wearing it. Florists also use these crystals as a dirt free way to store water and keep cut flowers fresh for a long time. It takes about forty five minutes to hydrate the typical headband or collar for duration ahead of time isn't necessary, but it does help extend the cooling time.
The same polymer crystals can be rehydrated many times. They'll dry out and form the crystals again, and then re expand when they're rewetted. Be sure to check out our new video podcast, Stuff from the Future. Join How Stuff Work staff as we explore the most promising and perplexing possibilities of tomorrow. The How Stuff Works I Fine app has arrived. Download it today on iTunes.