Abstract
Shaping ceramic materials at the nanoscale in 3D is a phenomenal engineering challenge, that can offer new opportunities in a number of industrial applications, including metamaterials, nano‐electromechanical systems, photonic crystals, and damage‐tolerant lightweight materials. 3D fabrication of sub‐micrometer ceramic structures can be performed by two‐photon laser writing of a preceramic polymer. However, polymer conversion to a fully ceramic material has proven so far unfeasible, due to lack of suitable precursors, printing complexity, and high shrinkage during ceramic conversion. Here, it is shown that this goal can be achieved through an appropriate engineering of both the material and the printing process, enabling the fabrication of preceramic 3D shapes and their transformation into dense and crack‐free SiOC ceramic components with highly complex, 3D sub‐micrometer architectures. This method allows for the manufacturing of components with any 3D specific geometry with fine details down to 450 nm, rapidly printing structures up to 100 µm in height that can be converted into ceramic objects possessing sub‐micrometer features, offering unprecedented opportunities in different application fields.
Highlights
Increased chemical durability, better wear and oxidation resistance, higher elastic modulus and improved dimensional stability with temperature.[9,10,11,12,13]
Shaping preceramic polymers sub-micrometer architectures. This method allows for the manufacturing of at the sub-micrometer scale while genercomponents with any 3D specific geometry with fine details down to 450 nm, rapidly printing structures up to 100 μm in height that can be converted into ceramic objects possessing sub-micrometer features, offering unprecedented opportunities in different application fields
We selected a few significant 3D shapes to validate the feasibility of shaping preceramic polymers at the sub-micrometer scale: the Kelvin cell (KC, Figure 1a–f) and the Diamond structure (DS, Figure 1g–n) represent examples of complex, porous, and highly detailed architectures which validate the possibility of generating long overhangs and demonstrate the freedom of 3D design that this technology affords, while woodpile structures were chosen because their simple shape allows to test the intrinsic limitation of the process in terms of the smallest feature dimensions achievable (Figure 2)
Summary
We selected a few significant 3D shapes to validate the feasibility of shaping preceramic polymers at the sub-micrometer scale: the Kelvin cell (KC, Figure 1a–f) and the Diamond structure (DS, Figure 1g–n) represent examples of complex, porous, and highly detailed architectures which validate the possibility of generating long overhangs and demonstrate the freedom of 3D design that this technology affords, while woodpile structures were chosen because their simple shape allows to test the intrinsic limitation of the process in terms of the smallest feature dimensions achievable (Figure 2). After pyrolysis at 1000 °C (Figure 1), no significant shape distortion in the 3D was observed This was achieved in spite of the overall linear shrinkages of 51% (KC) and 56% (DS), with respect to the printed structures (Figure 1) that, in terms of volume shrinkage, resulted in a contraction of almost 90%. A sufficient degree of crosslinking of the polymer should be achieved in a reasonable period, as fabrication time is a decisive parameter to develop a promising process technology. To this end, we conducted this work deliberately disregarding material formulations showing low throughput compared to standard two-photon resists
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