A New Framework for 3D Printing Aerogels with Additives: Hardware and Ink Development

The 3D printing of functional aerogels, particularly those incorporating additives, represents a transformative approach in materials science, enabling the creation of highly customizable structures with advanced properties. This study introduces a 3D printing methodology for fabricating aerogel structures infused with titanium dioxide (TiO₂) nanoparticles, designed to enhance photocatalytic and environmental remediation applications. A commercially available 3D printer was adapted with a custom syringe pump system, allowing precise control over the extrusion of a shear-thinning aerogel ink. The ink formulation, tailored for compatibility with the system, achieved homogeneous dispersion of TiO₂ nanoparticles (55-230 nm) within the silica aerogel matrix at 50 wt % relative to silica content. Postprocessing steps, including gelation in ammonia vapor and supercritical CO₂ drying, preserved the intricate geometries of printed structures, which achieved a specific surface area of 407 m²/g and a density of 0.15 g/cm³. Rheological analysis demonstrated the ink's suitability for 3D printing, with viscosity decreasing from 10,000 Pa·s to 1 Pa·s under shear, enabling smooth extrusion due to shear thinning behavior, and elastic moduli confirming strong structural integrity necessary for retaining printed shapes. This approach enabled 3D printing of aerogel structures with <1 mm precision. It provides a scalable and cost-effective pathway for producing functional aerogels with tailored properties for potential applications in catalysis, thermal insulation, and environmental remediation.