Skip to Content
MIT News: 77 Mass Ave

Diaper genius

An absorbent material used in disposable diapers could help produce water from dry air.

August 22, 2023
beads of absorbent gel
Gustav Graeber and Carlos D. Díaz-Marín

By infusing a salt into a material used in disposable diapers, MIT engineers have synthesized a superabsorbent gel that can soak up a record amount of moisture from even the driest air, offering a possible way to harvest drinkable water.

The transparent, rubbery material combines the advantages of lithium chloride, a salt that can absorb over 10 times its own mass in water, and hydrogel, which can hold the water and swell to accommodate even more. Researchers had previously tried to accomplish this by soaking hydrogels in salty water, but they found that after 24 to 48 hours, the gels took up very little salt and weren’t much more absorbent than they had been to start with.

But scientists at MIT’s Device Research Lab found that hydrogels soaked in the solution for 30 days incorporated up to 24 grams of salt per gram of gel—four times the previous record. The resulting material absorbed and retained an unprecedented amount of moisture across a range of humidity levels. Most notably, at very dry conditions of 30% relative humidity, each gram of salty gel captured 1.79 grams of water.

“This material, because of its low cost and high performance, has so much potential,” says Carlos Díaz-Marin, SM ’21, a mechanical engineering graduate student and a coauthor of a paper on the work. Conceivably, he says, it “could generate water in the desert.”

Keep Reading

Most Popular

DeepMind’s cofounder: Generative AI is just a phase. What’s next is interactive AI.

“This is a profound moment in the history of technology,” says Mustafa Suleyman.

What to know about this autumn’s covid vaccines

New variants will pose a challenge, but early signs suggest the shots will still boost antibody responses.

Human-plus-AI solutions mitigate security threats

With the right human oversight, emerging technologies like artificial intelligence can help keep business and customer data secure

Next slide, please: A brief history of the corporate presentation

From million-dollar slide shows to Steve Jobs’s introduction of the iPhone, a bit of show business never hurt plain old business.

Stay connected

Illustration by Rose Wong

Get the latest updates from
MIT Technology Review

Discover special offers, top stories, upcoming events, and more.

Thank you for submitting your email!

Explore more newsletters

It looks like something went wrong.

We’re having trouble saving your preferences. Try refreshing this page and updating them one more time. If you continue to get this message, reach out to us at with a list of newsletters you’d like to receive.