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This new material heals—not cracks—under pressure

What if you could reassemble your coffee cup like a LEGO set after it shattered on the floor? For years, researchers have been trying to develop healable polymers, but they’ve either been too soft to be practical, or they’ve required high temperatures to merge the pieces back together. Now, researchers have developed a new kind of semitransparent polymer called TUEG3 (poly[thioureas] and ethylene glycol), that maintains both rigidity and healing properties, without requiring any external heating. All that’s needed is a little bit of force. The healing process relies on hydrogen bonds, the electrostatic “glue” that keeps the polymer’s atoms together. The hydrogen bonds form in a such a way that the polymer doesn't crystallize, giving the molecular chains the ability to move freely, and easily combine when pieces of the substance are compressed. After being cut and gently compressed for 30 seconds, a 2-square-centimeter sheet of the new material can hold 300 grams of weight, roughly the same as a full can of soda, the researchers report today in Science. In the future, this rigid polymer could be used in the manufacturing of electronics, and maybe one day help put your mug back together before your coffee’s done brewing.