Liquid nanofoam liner adds resilience to American football helmets

This is the claim of Michigan State University researcher Weiyi Lu, an MSU assistant professor of civil and environmental engineering whose liquid nanofoam is described in the Proceedings of the National Academy of Sciences.

Microlattice padding makes for safer helmets

When a helmet withstands an impact severe enough to cause a concussion to the player wearing it, the safety features of the helmet are compromised, rendering equipment unsafe for further use, Lu said.

The material developed by Lu and his team to reverse this is said to be full of tiny nanopores.

"The pore diameters are between two and 200nm and that creates a large amount of surface area," Lu said. "The whole area of MSU's Spartan Stadium could be folded up into one gram of nanofoam."

Ordinarily, the material is rigid and adding liquid would fill the holes. To fix this, Lu and his team coated the nanopores with a hydrophobic silicone layer made from an organic silyl chain that prevents liquid from being absorbed by the material. As a result, the liquid inside the nanofoam material becomes pressurised during an impact.