The specific geometry has a crucial impact on the function of aerogel materials in application scenarios.However,conventional manufacturing technology remains challenging in the customized shaping of aerogels due to the fragility of aerogels,time-consuming manufacturing cycles,and poor designability of molds.Direct-write 3D printing technology has been applied to achieve the on-demand shaping of aerogels,imparting aerogels with compatible material composition and functional characteristics.In this work,a direct-write 3D printing strategy based on dual-channel intermixing extrusion was proposed to prepare polyimide-silica(OBS)aerogel composites.Benefiting from the efficient fluid diffusion intermixing between inks and catalysts during extrusion processes,chemical imidization solidification can be successfully achieved,and 3D-printed OBS aerogel composites show high structural integrity and high shape fidelity.Depending on the advantages of the spatial assembly of direct-write 3D printing technology,OBS aerogel composites have formed multi-scale morphologies of millimeters,micro-meters,and nanometers.In micron scale,the composite structure enables 3D-printed OBS aerogel composites to display excellent mechanical properties(Young's modulus up to 14.4 MPa).Meanwhile,nanoscale pore structure features,such as low density(0.208 g·cm-3),high surface area(373 m2·g-1),and concentrated poren diameter distri-bution(20-30 nm),impart 3D-printed OBS aerogel composites with excellent thermal insulation performance(thermal conductivity as low as 21.25 mW·m-1·K-1).Although our work only focuses on OBS aerogel composites,the successful implementation of this 3D printing strategy would provide guidelines for additive manufacturing of other aerogel composites.
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