Self-Healing and Interlayer Repair in Photopolymer Additive Manufacturing: Mechanisms, Network Mobility and Validation Limits
Segurola, Juan
2026-08-21 · Informe · Versión 1.4
Los títulos y las descripciones bibliográficas se conservan en el idioma del registro original. Los enlaces a los PDF indican los idiomas disponibles.
Photopolymer additive manufacturing normally converts a low-viscosity reactive formulation into a permanently crosslinked object. That transformation is advantageous for geometric fidelity and green strength, but it also restricts molecular mobility after cure and can leave layer interfaces, crack surfaces and damaged regions unable to re-establish load-bearing connectivity. A growing literature addresses this limitation through intrinsic dynamic covalent networks, supramolecular interactions, mobile linear-polymer phases, extrinsic healing agents and hybrid elastomer architectures. These approaches are often grouped under the term self-healing even though they solve different problems. Interlayer welding during or after fabrication is not the same experiment as restoring a severed specimen; visual crack closure does not prove recovery of fracture resistance; and a single tensile-strength ratio does not establish fatigue life, autonomous function or repeated repairability. This review organises photopolymer repair around four coupled variables: network mobility, interfacial contact, exchange or rebonding kinetics, and the mechanical quantity used to define recovery. Primary studies demonstrate that DLP- and stereolithography-compatible systems can incorporate disulfide exchange, transesterification, imine exchange, boronate-ester metathesis, ionic or hydrogen-bonded associations, and extrinsic solvent-welding strategies. Recent work also shows that dynamic chemistry can reduce, rather than universally eliminate, layer-dependent mechanical anisotropy. A minimum reporting framework is proposed for damage state, activation protocol, specimen orientation, controls, recovery metric, number of cycles, failure location and dimensional stability. The resulting framework defines a defensible boundary between post-cure strengthening, interlayer repair, intrinsic self-healing, reprocessing and functional recovery.