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Traditional aerogels are produced by sol-gel chemistry where a dilute polymer solution is taken to gelation. Polymer Aerogel 3D printing requires a high viscosity sol for stackable extrusion; however, this limits the time frame to print the materials prior to gelation. In response to this issue, NASA researchers have developed a novel dual solvent process to be used in additive manufacturing (3D printing). A dual-solvent formulation is employed during polymer aerogel precursor preparation to enable 3D printing of self-supporting structures. The system combines a high–boiling point aprotic solvent, which supports polymerization and network formation during aerogel synthesis, with a secondary low–boiling point solvent that partially evaporates during extrusion and printing. Preferential evaporation of the low–boiling component increases the local solids concentration and material viscosity at the nozzle and immediately after deposition, enabling filament stackability and shape retention without premature gelation. This approach decouples printability from bulk gel chemistry, allowing precise control of rheology during printing while preserving the desired aerogel microstructure and porosity after drying. A Two-Pot System: • Pot 1 contains a cross-linked polyamic acid solution and acetic anhydride or water scavenger, dissolved into a mix of high and low boiling point solvents (e.g., Dimethyl Sulfoxide (DMSO), n-methylpyrrolidone (NMP), or Dimethylformadie (DMF), with acetone or tetrahydrofuran (THF), ethanol, or methanol. • Pot 2 contains a base catalyst (e.g., trimethylamine or pyridine) and optionally a thickening agent (e.g., polyvinyl alcohol or polyvinyl acetate) to match viscosities. Dual-Solvent Chemistry: The low boiling point solvent evaporates rapidly upon extrusion, increasing the polymer concentration and viscosity, allowing the aerogel to retain its shape and gel quickly. • Additive Manufacturing Process: The two solutions are mixed at the extrusion tip of a syringe/nozzle-based 3D printer. This enables low-viscosity flow pre-extrusion and rapid solidification post-extrusion—solving a key challenge in 3D printing aerogels.

To overcome the challenges of conventional molding, researchers at NASA Glenn have developed a rapid prototyping approach for three-dimensional printing of polymer aerogels using deposition into a viscous, sacrificial support medium. The sacrificial support stabilizes the aerogel deposition, allowing precise layer-by-layer construction of self-supporting aerogel networks that would otherwise be unprintable in air. Following printing and gelation of the polymer network, the printed structure is gently removed from the sacrificial medium, yielding a freestanding aerogel precursor with high shape fidelity. This method decouples printability from intrinsic material viscosity and enables rapid iteration of aerogel geometries, offering a scalable pathway for additive manufacturing of ultra-lightweight, architected polymer aerogels with tailored geometries, while retaining microstructural, mechanical, and thermal properties. The method involves: 1. Forming a solution comprised of a polymer precursor, cross-linker, solvent, and catalyst to create a dilute polymer solution. 2. 3D printing the polymer precursor directly into the sacrificial support medium. 3. Following printing and network formation, the structure is removed from the sacrificial medium through a low-stress extraction process, yielding a freestanding polymer aerogel precursor that retains the as-printed geometry with high fidelity. The sacrificial medium functions as a temporary, conformal support matrix that stabilizes each deposited droplet or filament in situ, enabling freeform construction of aerogel. This strategy enables the fabrication of highly porous, interconnected networks with controlled feature resolution across multiple length scales, while maintaining the intrinsic low density and high surface area required for aerogel performance.