Etched glass stops cracks in their tracks

Carving squiggly lines into glass can actually toughen it up. The new engraving technique could keep wine glasses, windowpanes and medical implants from shattering. It might even beef up bulletproof glass.

Ordinary bulletproof glass relies on a sandwich of glass, plastic and a rubbery glue called polyurethane to absorb the impact of speeding projectiles. Francois Barthelat and colleagues at McGill University in Montreal used a different strategy to cushion a blow.

The researchers laser cut a wavy pattern of tiny holes into glass microscope slides and then filled the pattern with polyurethane. Just as paper rips along a perforated line, the etched glass cracked along the patterns when researchers stressed it.

But the curvy patterns lock the glass together, like puzzle pieces. These interlocking pieces absorb energy, so a crack that would normally zip through the brittle material petered out instead, the team reports in the Jan. 28 Nature Communications.

Biology inspired the researchers to strategically position weak spots that guide cracks to tough-to-break areas, Barthelat says: “This kind of trick is used in bones, teeth and seashells — any hard material you can think of in nature.”