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three-dimensional (3d) resilient nanostructures, such as graphene monoliths (1, 2), carbon nanotube aerogels (3), polymer foams (4), and metal microlattices (5, 6), have been synthesized and explored for a wide range of applications, including tissue engineering, thermal insulation, energy storage, filtration, and environmental protection (710). although these 3d nanostructures generally exhibit superior properties, including high porosity, large surface area, reliable mechanical properties, and ultralow density (11, 12), applications at high temperatures in air still remain challenging because of their relatively unstable constituent materials (carbon, polymers, and metals). in contrast, ceramics feature high strength and good mechanical/chemical stability at high temperatures (13, 14), but their brittleness and flaw sensitivity have so far limited the development of lightweight and resilient ceramic systems (15, 16).
microarchitectural cellular structures made of nanoceramics (17) and nanoceramic composites (18) are typically brittle despite many superior properties, including substantially enhanced specific stiffness and strength. more recently, a compelling hollow-tube alumina nanolattice structure, with tube wall thickness of 5 to 60 nm, tube major axis around 1 m, and whole-cell width of 25 to 75 m, has been recently fabricated based on two-photon lithography direct laser writing (dlw), atomic layer deposition, and oxygen plasma etching (19). deformation in this nanolattice appears to be dominated by elastic buckling of the tube shell, leading to substantial ductility and good recoverability under uniaxial compression at room temperature. however, this nanolattice is generally limited to below 1 mm in size and cannot easily scale up to larger systems because of its dlw-based synthesis process. nanoporous monolithic alumina and lanthanide oxide aerogels (2023) have been synthesized via sol-gel and self-assembly methods. these aerogels exhibit ultralow density and excellent thermal properties, but their specific modulus and strength are much lower than those of nanolattices (19). to date, there has been no investigation on the high-temperature resilience of lightweight ceramic cellular structures.
it has recently been recognized that ceramic nanocrystalline nanofibers are highly flexible because of their high aspect ratios and nanometer-sized grains (24, 25) and can be an ideal candidate for building blocks for 3d elastic assemblies (26). a variety of ceramic nanofibers have been successfully prepared through electrospinning, which uses an electric field to draw fibers from precursor solutions (27). however, electrospun nanofibers typically form a thin film network of random or oriented nanofibers and cannot be easily assembled into large-scale 3d networks because of intrinsic limitations in the electrospinning technique. here, we report the manufacturing of large-scale 3d sponges based on a variety of ceramic [for example, tio2, zro2, yttria-stabilized zro2 (ysz), and batio3] nanofibers through an economic and efficient blow-spinning technique. quantitative mechanical testing indicated that the nanofiber sponges exhibit excellent resilience at both room and high temperatures up to 800c, and we also observed mechanical resilience of the ysz nanofiber sponge at even higher temperatures (~1300c). the ceramic nanofiber sponges also exhibit ultralow density, superior mechanical/chemical stability, efficient energy absorption during cyclic loading, and multifunctionalities, such as elasticity-dependent electrical resistance, photocatalytic activity, and thermal insulation.
90 אחוז מזה לא חשוב, הצלחתם להבין בתכלס מה העיקר? באיזה מכשיר השתמשו?
three-dimensional (3d) resilient nanostructures, such as graphene monoliths (1, 2), carbon nanotube aerogels (3), polymer foams (4), and metal microlattices (5, 6), have been synthesized and explored for a wide range of applications, including tissue engineering, thermal insulation, energy storage, filtration, and environmental protection (710). although these 3d nanostructures generally exhibit superior properties, including high porosity, large surface area, reliable mechanical properties, and ultralow density (11, 12), applications at high temperatures in air still remain challenging because of their relatively unstable constituent materials (carbon, polymers, and metals). in contrast, ceramics feature high strength and good mechanical/chemical stability at high temperatures (13, 14), but their brittleness and flaw sensitivity have so far limited the development of lightweight and resilient ceramic systems (15, 16).
microarchitectural cellular structures made of nanoceramics (17) and nanoceramic composites (18) are typically brittle despite many superior properties, including substantially enhanced specific stiffness and strength. more recently, a compelling hollow-tube alumina nanolattice structure, with tube wall thickness of 5 to 60 nm, tube major axis around 1 m, and whole-cell width of 25 to 75 m, has been recently fabricated based on two-photon lithography direct laser writing (dlw), atomic layer deposition, and oxygen plasma etching (19). deformation in this nanolattice appears to be dominated by elastic buckling of the tube shell, leading to substantial ductility and good recoverability under uniaxial compression at room temperature. however, this nanolattice is generally limited to below 1 mm in size and cannot easily scale up to larger systems because of its dlw-based synthesis process. nanoporous monolithic alumina and lanthanide oxide aerogels (2023) have been synthesized via sol-gel and self-assembly methods. these aerogels exhibit ultralow density and excellent thermal properties, but their specific modulus and strength are much lower than those of nanolattices (19). to date, there has been no investigation on the high-temperature resilience of lightweight ceramic cellular structures.
it has recently been recognized that ceramic nanocrystalline nanofibers are highly flexible because of their high aspect ratios and nanometer-sized grains (24, 25) and can be an ideal candidate for building blocks for 3d elastic assemblies (26). a variety of ceramic nanofibers have been successfully prepared through electrospinning, which uses an electric field to draw fibers from precursor solutions (27). however, electrospun nanofibers typically form a thin film network of random or oriented nanofibers and cannot be easily assembled into large-scale 3d networks because of intrinsic limitations in the electrospinning technique. here, we report the manufacturing of large-scale 3d sponges based on a variety of ceramic [for example, tio2, zro2, yttria-stabilized zro2 (ysz), and batio3] nanofibers through an economic and efficient blow-spinning technique. quantitative mechanical testing indicated that the nanofiber sponges exhibit excellent resilience at both room and high temperatures up to 800c, and we also observed mechanical resilience of the ysz nanofiber sponge at even higher temperatures (~1300c). the ceramic nanofiber sponges also exhibit ultralow density, superior mechanical/chemical stability, efficient energy absorption during cyclic loading, and multifunctionalities, such as elasticity-dependent electrical resistance, photocatalytic activity, and thermal insulation.
90 אחוז מזה לא חשוב, הצלחתם להבין בתכלס מה העיקר? באיזה מכשיר השתמשו?
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