Hierarchically porous ceramics via direct writing of preceramic polymer-triblock copolymer inks
Hierarchically porous ceramics via direct writing of preceramic polymer-triblock copolymer inks
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DOI：
10.1016/j.mattod.2022.07.002
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发表时间：
2022-09-01
期刊：
影响因子：
24.2
通讯作者：
Dickerson，Matthew B.
中科院分区：
文献类型：
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作者：
Bowen，John J.;Mooraj，Shahryar;Dickerson，Matthew B.
分级多孔陶瓷在多个长度尺度上具有定制的孔隙率，从而产生具有低密度、高比性能和多功能性的材料。在这里，我们报告了一种结合自组装和3D打印的方法，以创建具有从纳米到微米级的分层孔隙率的陶瓷架构。为了可编程地定义其微尺度孔隙率，使用被称为直接墨水写入的增材制造方法来创建由圆柱形支柱组成的3D晶格。通过嵌段共聚物模板化，然后在非氧化环境中进行光聚合和热解，在每个支柱内产生纳米级孔隙率，将预陶瓷聚合物聚碳硅烷转化为具有“纳米珊瑚”形态的碳氧化硅。所得的分级多孔陶瓷晶格表现出优异的机械能吸收（0.31 MJ/m3），与金属合金泡沫相当。它们还具有一个数量级较低的热导率（0.087-0.16 W/m·K）相比，体预陶瓷聚合物衍生的陶瓷。在热解之前，可以操纵打印的结构以产生更复杂的形状，包括具有扭曲、螺旋和悬垂特征的晶格以及重复折叠以创建折纸飞机。通过结合自我和定向组装，我们的方法开辟了新的途径，创造层次多孔陶瓷。
Hierarchically porous ceramics possess tailored porosity across multiple length scales, giving rise to materials with low density, high specific properties, and multifunctionality. Here, we report a method that combines self-assembly and 3D printing to create ceramic architectures with hierarchical porosity spanning from the nano- to microscale. To programmably define their microscale porosity, an additive manufacturing method, known as direct ink writing, is used to create 3D lattices composed of cylindrical struts. Nanoscale porosity is generated within each strut by block copolymer templating followed by photopolymerization and pyrolysis in a non-oxidative environment, which transforms the preceramic polymer, polycarbosilane, into silicon oxycarbide with a “nanocoral” morphology. The resulting hierarchically porous ceramic lattices exhibit excellent mechanical energy absorption (0.31 MJ/m3), comparable to metal alloy foams. They also possess an order of magnitude lower thermal conductivity (0.087–0.16 W/m⋅K) compared to bulk preceramic polymer-derived ceramics. Prior to pyrolysis, the printed architectures can be manipulated to produce more complex shapes, including lattices with twisted, helical, and overhang features as well as repeated folding to create an origami airplane. By combining self- and directed assembly, our approach opens new avenues for creating hierarchically porous ceramics.