Advancements in Strong and Tough Materials
Strength, durability, reliability. These are all desirable traits to have in a given material. Constant advancements are made in this arena and it can be difficult to keep up with them all. Therefore, here is my attempt to present a few of them and hopefully whet your appetite for finding more. After all, it is an exciting field with constant surprises!
Slippery yet Strong
Imagine if we could make steel, already a versatile material, even better by giving it protection from the elements. Scientists from the Wyss Institute for Biologically Inspired Engineering at Harvard University let by Joanna Aizenberg accomplished this with their development of SLIPS. This is a coating that can adhere to steel courtesy of “nanoporous tungsten oxide” deposited onto a steel surface with electrochemical means, and its ability to repel liquids even after surface wear is impressive. This is especially so when we take into account how difficult it is to get a nanomaterial that is both strong enough to withstand impacts yet also sophisticated enough to dispel with certain elements. This was overcome via an island-like design for the coating, where if one piece is damaged then only it is impacted while the other potions remain intact (Burrows).
Oftentimes when we make something we can cause an irreversible change, like deforming a surface with an impact or a compression. Normally, once done there is no going back. So when researchers from Rice University announced the development of a self-adaptive composite (SAC), it seems to be impossible upon first glance. This liquid (which seams solid) is made of “tiny spheres of polyvinylidene fluoride” which are coated with polydimethylsiloxane, it is created once the material is heated and the spheres form a matrix that not only returns to its original shape well but also heals itself by re-adhering if a tear is initiated. It fixes itself, people! That is awesome! (Ruth).
Good ol’ nature has given man many materials to try and replicate. But not many would think we have lessons to be learned from the teeth of squid, yet that is exactly what scientists led by Melik Demirel found was the case. After examining the teeth from Hawaiian bobtail squid, the long-finned squid, the European squid, and the Japanese flying squid, scientists looked at how the multiple proteins present interplayed with each other by manufacturing their own. They found interesting interplays between “crystalline and amorphous phases” as well as the repeating amino acid strings known as polypeptides. The team found that as the weight of their synthesis proteins grew, so did the toughness. And to increase the weight the polypeptide chain needed to grow out also. Interestingly, the elasticity and plasticity of their material did not alter significantly as the chain length was grown. The material is also highly adaptable and self-repairing, much like SAC (Messer).
Shrimp This Time
Now let’s look at a different water lifeform: Mantis shrimp. These creatures manage to eat by destroying their food’s shell with a dactyl club, which has to be strong to withstand such punishment constantly. Researchers from the University of California, Parkside and Purdue University were naturally curious as to how the club is able to achieve this, and they found the first known example of a herringbone structure in nature. This is a layered fiber approach which is sinusoidal-shaped stacks of helicoidal chitin fibers along with calcium phosphate. Under this layer is the periodic region, and mantis shrimp have it filled with an energy-absorbing material that transfers the residual impact to prevent damage to the creature. This material is composed of chitin (what your hair and fingernails are made of) arranged much like a single helix and is also made of amorphous calcium phosphate and calcium carbonate. All in all, this club may someday be replicated via a 3D printing to further improve impact technology (Nightingale).
We all get those pesky scratches on our displays, our phones, essentially the equipment that we use all the time and therefore cannot avoid getting them, right? Well, scientists from the Queen’s University’s School of Mathematics and Physics found that hexagonal boron nitride or h-BN (a lubricant that is used in the car industry) creates a strong yet rubber-like material that is resistant to indentations, making it an ideal covering for materials we wish to be scratch-proof. This is owed to the hexagonal-structure of the material’s subunits. And because of its nanoscale it would be essentially transparent to us, making it even better as a protective layer (Gallagher).
We have had some geometrical implications up to this point, so why not delve into a special section known as tessellations. These amazing mathematical structures form patterns that seem to continue on forever and ever, much like tiling implies. A team from the Technical University of Munich has found a way to translate this feature to the material world, normally a difficult prospect because of the size of the molecules used. It just doesn’t translate to anything useful because they end up being too big to fix to anything else. With the new research, scientists were able to manipulate ethynyl iodophenanthrene with a silver center to create a tiling “in a self-organized manner” with hexagons, squares, and triangles forming at semi-regular intervals. For the math people (like me) out there, this translates to a 184.108.40.206 tessellation. Such a structure is incredibly rigid, providing new opportunities to enhance the strength of different materials (Marsch).
What will come next? What sturdy material is on the horizon? Come back sometime soon for the latest updates!
Burrows, Leah. “Super-slick material makes steel better, stronger, cleaner.” Innovations-report.com. innovations report, 20 Oct. 2015. Web. 14 May 2019.
Gallagher, Emma. “Research team discovers ‘rubber material’ that could lead to scratch-proof paint for car.” Innovations-report.com. innovations report, 08 Sept. 2017. Web. 15 May 2019.
Marsch, Ulrich. “Complex tessellations, extraordinary materials.” Innovations-report.com. innovations report, 23 Jan. 2018. Web. 15 May 2019.
Messer, A’ndrea. “Programmable materials find strength in molecular repetition.” Innovations-report.com. innovations report, 24 May 2016. Web. 15 May 2019.
Nightingale, Sarah. “Mantis shrimp inspires next generation of ultra-strong materials.” Innovations-report.com. innovations report, 01 Jun. 2016. Web. 15 May 2019.
Ruth, David. “Self-adaptive material heals itself, stays tough.” Innovations-report.com. innovations report, 12 Jan. 2016. Web. 15 May 2019.
© 2020 Leonard Kelley