New material may pave the way for lighter weight body armor
Marie Donlon | January 20, 2025A team of Northwestern University researchers has developed what it claims is the first 2D mechanically interlocked material, which promises to potentially lead to improved light-weight body armor.

To create the material, the team used a new polymerization process.
“We made a completely new polymer structure,” the researchers explained. “It’s similar to chainmail in that it cannot easily rip because each of the mechanical bonds has a bit of freedom to slide around. If you pull it, it can dissipate the applied force in multiple directions. And if you want to rip it apart, you would have to break it in many, many different places. We are continuing to explore its properties and will probably be studying it for years.”
Researchers had previously tried to create mechanically interlocked molecules with polymers but encountered difficulties in encouraging polymers to form mechanical bonds. To address this issue, the team began with X-shaped monomers, which are the basic units of polymers, and organized them into a specific, highly ordered crystalline structure. They then reacted these crystals with another molecule to form bonds between the molecules within the crystal.
Those crystals, the team added, comprise layers of 2D interlocked polymer sheets and within those polymer sheets, the ends of the X-shaped monomers adhered to the ends of other X-shaped monomers. Meanwhile, more monomers are then threaded through the gaps that exist in between.
Further, regardless of the material’s rigid structure, the polymer proved during testing to be unexpectedly flexible. Likewise, the team found that dissolving the polymer in solution encouraged the layers of interlocked monomers to peel off each other.
“After the polymer is formed, there’s not a whole lot holding the structure together,” the team added. “So, when we put it in solvent, the crystal dissolves, but each 2D layer holds together. We can manipulate those individual sheets.”
Unlike previously developed polymers that were prepared in very small quantities, the researchers explained that the new material can be manufactured in large quantities.
The team added the new polymer to Ultem, a material capable of withstanding extreme temperatures as well as acidic and caustic chemicals, resulting in a composite material of 97.5% Ultem fiber and 2.5% of the 2D polymer. That small percentage of the 2D polymer increased Ultem’s overall strength and toughness dramatically.
The team envisions that the new polymer could potentially be used in body armor and ballistic fabrics.
The study, “Mechanically interlocked two-dimensional polymers,” appears in the journal Science.