Polyimide and Polyimide-Precursor Photopolymers for Vat Photopolymerisation: Chemical Identity, Organogel Formation, Imidisation, Shrinkage, Void Formation and High-Temperature Qualification

All-aromatic polyimides combine thermal stability and mechanical performance with poor melt or solution processability in their final imidised state. Light-based additive manufacturing therefore commonly prints a soluble and photosensitive precursor, fixes geometry by a temporary photocrosslinked scaffold and then uses solvent removal plus thermal imidisation to form the target polyimide. Primary studies demonstrate mask-projection stereolithography of photoacrylated polyamic esters, photocurable polyamic-acid salts, concentrated supramolecular polysalts, two-photon writing of a commercial negative photosensitive precursor and structure–morphology differences between polyimide variants. The process can retain complex geometry, but reported linear shrinkage includes approximately 52% in a dilute organogel strategy and 19 ± 1% for a two-photon precursor under its cure schedule. These route-specific values cannot be pooled or transferred to concentrated polysalt systems without primary confirmation. Solvent transport, crosslink removal, cyclodehydration by-products, thermal gradients and constraint determine warping, cracking and internal voids. A 2026 morphology study observed prevalent internal voids at and above 350 °C under its conditions, with chemistry-dependent severity. ER-105 separates precursor, gel, partially imidised and final states; defines mass, dimension and chemistry closure; and requires final-state thermal, mechanical and component verification. It does not grant Kapton equivalence, universal service temperature, electrical qualification, low outgassing, biocompatibility or fire performance.

3Dresyns Engineering Review ER-105, version 0.3. Provider-neutral technical review. The deposited PDF is controlled by its exact SHA-256 in the release manifest.