- The new material can withstand being shot at by bullets traveling at 3.6 miles per second.
- It is extremely impressive considering the fact that this material is highly compressive, made of plastic, and contains several holes.
In material design, lightweight materials with high load-bearing capabilities and intense impact resistance are regarded as a holy grail. Such natural materials usually have optimized, complex geometries.
A broad range of biomaterials such as seashells, kingfisher beaks, shark teeth, and bones have highly controlled structures in different length scales from macrometer to submicrometer. Significant efforts have been made to understand how these materials get exhibit exceptional mechanical performance.
Mimicking properties of such materials (for example, their lightweight structure and high load-bearing capabilities) is always challenging due to the lack of effective synthesis techniques.
Recently, researchers at Rice University presented exciting new methods for developing materials based atomic-scale structures, which are currently synthetically inaccessible or extremely hard to produce.
Using these methods, they were able to 3D print a lightweight material that is nearly as hard as diamond. The novel material is bulletproof, despite the fact that it is made of plastic and contains several holes.
It can withstand being shot at by bullets traveling at 3.6 miles per second. And unlike diamonds and other brittle materials, they can be highly compressed.
The research team analyzed the structural and mechanical behavior of structures with tubulane architecture. Tubulanes are nothing but a 3D porous carbon allotrope structures that contain highly cross-linked carbon nanotubes. They are first predicted in 1993.
A total of 11 tubulane structures have been proposed but none of them have been made yet. However, researchers believe that their polymer cousins may be the next big thing.
Reference: Small | DOI:10.1002/smll.201904747 | Rice University
They tested 3 of the theoretical structures to see whether these tubulane materials can retain their extraordinary mechanical properties when they are scaled up enough to be 3D printed (or seven orders of magnitude larger).
It turns out the answer is yes. They described the material in detail along with topological effects and molecular dynamics simulation results.
Tests and Applications
Researchers 3D printed macroscale polymers and tested them against speeding bullets and crushing forces. The best sample handled the impact of a bullet 10 times better than a solid cube built from the same material.
More specifically, the bullet stopped in the 2nd layer of the tubulane-like polymer structure, without any substantial damage noticed beyond that layer. Whereas, the solid cube was entirely cracked by the bullet fired at the same speed.
3D printed polymer blocks (gray) and a solid cube (yellow) made of the same material | Credit: Jeff Fitlow
The compressive load test showed that porous polymer lattice makes tubulane blocks collapse in upon themselves without causing cracks. It exhibited a remarkable resilience to mechanical deformation.
Since the exceptional properties of tubulane-like structures (made of polymer, ceramic and metal) come from their complex topology they are only limited by the 3D printer size. It is possible to create better materials by optimizing the lattice design.
These materials could have applications in various fields, ranging from biomedical and packaging to aerospace and automotive. They can also be used for well construction for storing oil/gas, and rubblization of standard cement.