Freezing‐Assisted Direct Ink Writing of Customized Polyimide Aerogels with Controllable Micro‐ and Macro‐ Structures for Thermal Insulation.

Polyimide (PI) aerogels have attracted attention in thermal management due to their low thermal conductivity, high porosity, and robust mechanical properties. However, building PI aerogels with elaborately tailored micro‐ and macro‐ structures for optimized thermal insulation performance in specific scenarios remains a challenge. Here, a scalable approach is reported to prepare PI aerogels with controllable micro‐ and macro‐ structures by freezing‐assisted direct ink writing (FADIW) of poly(amic acid) (PAA) inks. This FADIW strategy can enable continuous ink deposition and transient low‐temperature‐induced gelation, contributing to the facile construction of spatially free geometries with structural complexity and shape fidelity. Importantly, controllable construction of microstructures of the aerogels is achieved by controlling the extrusion substrate temperature. The resulting customized PI aerogels show good thermal insulation owing to the porous microstructure and customized macrostructure, enabling good thermal management for portable electronics. In addition, this FADIW strategy is universal and allows for multi‐material integration, broadening the functionality of PI aerogels. Significantly, such FADIW approach can be promisingly applied to realize on‐demand design of PI aerogels and other polymer aerogels with targeted micro‐ and macro‐structures, offering an alternative avenue for the manufacture of customized aerogels toward widespread applications. [ABSTRACT FROM AUTHOR]