Materials science performs a vital position in house exploration. So lots of the challenges dealing with each crewed and non-crewed missions come right down to components like weight, thermal and radiation tolerance, and total materials stability. The outcomes of a brand new examine from Younger-Kyeong Kim of the Korea Institute of Science and Know-how and their colleagues ought to subsequently be thrilling for these materials scientists who deal with radiation safety. After a long time of attempting, the authors have been in a position to create a totally full “sheet” of Boron Nitride Nanotubes (BNNTs).
BNNTs have been on the radar of various completely different functions in house exploration, however one of many greatest one is radiation shielding. Boron – one in all their main parts – is broadly used within the management rods of nuclear reactors attributable to its wonderful neutron absorbing properties. Research had proven that BNNTs are significantly efficient at limiting a selected sort of harmful neutron referred to as a “second neutron”, that are created when high-energy particles hit different varieties of shielding and shatter the atoms of no matter materials that defend is made out of. Prior to now, designers have used aluminum, however it had the drawback of being comparatively heavy, which is at all times a drawback in house functions.
Given their a lot lighter weights for a similar quantity of radiation shielding, BNNTs have lengthy been sought as a possible resolution to this downside. Nevertheless, they’ve suffered from manufacturability issues since their first experimental synthesization in 1995. They have been sometimes made utilizing a method known as vacuum filtration, and resulted in a fabric referred to as “bucky paper”. This course of, whereas efficient at creating dense clumps of BNNTs, couldn’t successfully unfold them over the entire floor required to create an efficient radiation defend.
NASA Video in regards to the hazards of radiation on human spaceflight. Credit score – NASA Movies YouTube Channel
Enter the brand new analysis from Dr. Kim and their colleagues. A part of the issue is that BNNTs hate water, and have a tendency to clump collectively when uncovered to it moderately than unfold themselves simply. Usually this downside is solved utilizing a surfactant – an additive chemical that coats the nanotubes to guard them from one another after they would in any other case clump up. The issue with utilizing normal surfactants is that the additional surfactant itself would begin clumping collectively, forming pockets within the materials known as micelles. These micelles really push the BNNTs, eliminating the dispersion impact the surfactants surrounding them try to implement.
Nevertheless, the brand new analysis makes use of a unique sort of surfactant. Dodecylbenzenesulfonic acid (DBSA) may sound intimidating to anybody who hasn’t taken natural chemistry shortly, however it’s a widespread ingredient in hand cleaning soap. The way in which it interacts with the BNNTs is completely different than conventional surfactants, making a bilayer of molecules that each protected the BNNTs from the water, but in addition didn’t kind the micelles that precipitated them to clump again collectively. This created a fabric state referred to as a Lyotropic Liquid Crystal, the place the nanotube aligned all in the identical path.
Alignment is vital when depositing them onto a floor, and that’s precisely what the researchers did utilizing a coating approach known as Physician Blade. That approach makes use of the shear drive of the created crystal rubbing in opposition to a substrate to drive the nanotubes to be deposited in a uniform construction, which has all the advantages of a BNNT sheet with none of the holes or gaps related to conventional manufacturing strategies.
TEDx discuss in regards to the potential of BNNTs. Credit score – TEDx Talks YouTube Channel
To show their newly fashioned materials really had higher radiation properties, the authors ran a simulation that in contrast the quantity of radiation passing by their BNNT movie and an identical quantity of aluminum. What they discovered was hanging – to get an equal quantity of radiation safety from aluminum would require 8x the load. In house exploration phrases, which means it might be ⅛ the worth to ship the identical quantity of radiation shielding to orbit.
Fairly spectacular stuff, although to be honest it has but to be virtually examined on an precise spacecraft. The fabric itself has to endure every kind of stresses and strains on its solution to house. BNNTs ought to have the bodily properties to resist it, however till its confirmed it stays an assumption. However, after 30 years within the lab, the promise of this radiation-resistent materials is lastly coming to fruition, and it is now poised to alter the way forward for radiation safety.
Study Extra:
Korean Nationwide Analysis Council of Science & Know-how – Blocking space radiation threats with nanotubes! ‘Boron nitride nanotube space radiation shield’ developed
Y.Ok. Kim et al – High-Density Boron Nitride Nanotube Composites via Surfactant-Stabilized Lyotropic Liquid Crystals for Enhanced Space Radiation Shielding
UT – A New Method to Make Lighter Radiation Shielding For Spacecraft: Rust.
UT – We Know How A lot Radiation Astronauts Will Obtain, However We Do not Know Methods to Forestall it
