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3D Printable Polymer Aerogels Using a Two-Pot Dual Solvent Method
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.



