” Embarking on understanding how the knots would affect the mechanical action of micro-architected materials was a new out-of-the-box concept,” Greer says. While these are not the smallest knots ever made– in 2017 chemists connected a knot made from a specific hair of atoms– this does represent the first time that a product composed of various knots at this scale has ever been created. Further, it shows the prospective worth of including these nanoscale knots in a product– for example, for suturing or tethering in biomedicine.
The samples detailed in the Science Advances paper contain easy knots– an overhand knot with an additional twist that offers extra friction to absorb extra energy while the product is stretched. In the future, the group plans to explore products built from more complicated knots.
The knotted products, which were produced out of polymers, exhibit a tensile strength that far surpasses products that are unknotted however otherwise structurally similar, including ones where private strands are interwoven instead of knotted. Credit: Caltech
Caltech engineers have actually made a considerable breakthrough in the field of nano- and micro-architected materials by creating a novel material made up of numerous interconnected microscale knots.
Compared to unknotted but structurally similar materials, the existence of knots in this new material significantly boosts its toughness by allowing it to soak up more energy and deform more before going back to its original shape without any damage. These new knotted products may discover applications in biomedicine along with in aerospace applications due to their toughness, possible biocompatibility, and severe deformability.
Moestopo is the lead author of a paper on the nanoscale knots that was released on March 8 in Science Advances.
Moestopo helped develop the material in the laboratory of Julia R. Greer, the Ruben F. and Donna Mettler Professor of Materials Science, Mechanics and Medical Engineering; Fletcher Jones Foundation director of the Kavli Nanoscience Institute; and senior author of the Science Advances paper. Greer is at the leading edge of the development of such nano-architected materials, or products whose structure is developed and organized at a nanometer scale which as a result display unusual, often surprising residential or commercial properties.
The tensile strength of a material constructed with microscale knots (left), compared to that of a product that lacks knots however is otherwise structurally identical (right). Credit: Caltech
” Embarking on comprehending how the knots would affect the mechanical response of micro-architected materials was a brand-new out-of-the-box concept,” Greer says. “We had actually done extensive research study on studying the mechanical contortion of lots of other types of micro-textiles, for instance, lattices and woven materials. Venturing into the world of knots allowed us to acquire deeper insights into the role of friction and energy dissipation, and proved to be meaningful.”
Each knot is around 70 micrometers in height and width, and each fiber has a radius of around 1.7 micrometers (around one-hundredth the radius of a human hair). While these are not the tiniest knots ever made– in 2017 chemists connected a knot made from an individual hair of atoms– this does represent the very first time that a product composed of various knots at this scale has actually ever been created. Further, it shows the possible value of consisting of these nanoscale knots in a product– for instance, for suturing or tethering in biomedicine.
The knotted products, which were produced out of polymers, show a tensile durability that far surpasses products that are unknotted but otherwise structurally similar, consisting of ones where individual hairs are interwoven rather of knotted. When compared to their unknotted equivalents, the knotted materials absorb 92 percent more energy and need more than two times the amount of pressure to snap when pulled.
The knots were not tied but rather manufactured in a knotted state by utilizing sophisticated high-resolution 3D lithography capable of producing structures in the nanoscale. The samples detailed in the Science Advances paper contain easy knots– an overhand knot with an additional twist that provides additional friction to take in additional energy while the material is extended. In the future, the group plans to check out products constructed from more intricate knots.
Moestopos interest in knots outgrew research study he was performing in 2020 throughout the COVID-19 lockdowns. “I discovered some works from scientists who are studying the mechanics of physical knots instead of knots in a purely mathematical sense. I do rule out myself a climber, a sailor, or a mathematician, but I have connected knots throughout my life, so I thought it deserved trying to insert knots into my designs,” he states.
Referral: “Knots are not for naught: Design, residential or commercial properties, and geography of hierarchical linked microarchitected materials” by Widianto P. Moestopo, Sammy Shaker, Weiting Deng and Julia R. Greer, 8 March 2023, Science Advances.DOI: 10.1126/ sciadv.ade6725.
The research study was moneyed by the National Science Foundation through Moestopos Graduate Research Fellowship Program, Caltechs Clinard Innovation Fund, Greers Vannevar Bush Faculty Fellowship, and the Office of Naval Research.