Hierarchical three-dimensional (3D) aerogels and foams based on carbon and related nanomaterials, e.g. graphene and CNTs, have been shown to hold great promise for a multitude of applications due to their unique set of electrical, mechanical and thermal properties. A special class of 3D nanostructured assemblies are so-called aeromaterials, consisting of an interconnected network of hollow microtubes with a wall-thickness below 25 nm. Due to their framework-like structure and porosity in the order of 99.99% aeromaterials are characterized by a completely different set of properties compared to conventional aerogels. For example, aeromaterials based on h-BN have been demonstrated to hold great promise as diffuser materials for the development of high-brightness laser-based light sources. [1] Graphene-based aeromaterials can be utilized to enable electrically powered and repeatable air explosions, enabling new electro-pneumatic micropumps and actuators for soft-robotics [2].

However, while various studies have demonstrated the great potential of this material class, up-scaling these materials remains challenging. Currently, the fabrication of the aeromaterials is based on a sacrificial template of tetrapod-shaped zinc oxide microparticles. The template is wet-chemically coated with a dispersion of 2D nanomaterials [3]. Subsequently, the template is removed by wet-chemical etching and dried using critical point drying. While the templates can be produced in different geometries and volumes (> 20 cm³), etching and drying processes are extremely time consuming, expensive, and drastically limit the aeromaterial volumes that can be fabricated to ~2 cm³. In this work, an alternative process based on dry-chemical etching with forming gas will be demonstrated, that can be utilized to upscale the fabrication of different aeromaterials, increasing their applicability in an industrial context. It will be shown, how different process parameters, such as temperature, gas flow and etching time influence the etching and overall process efficiency. At an optimized parameter set, the fabrication time can be reduced from one week to around one day.