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The relationship between fracture‐induced mechanophore activation and the strain and stress ahead of a propagating crack in poly(methyl methacrylate) (PMMA) is studied. The mechanophore spiropyran is used as a secondary cross‐linker in rubber toughened PMMA, and the spiropyran‐linked material is subjected to fracture testing. Mechanophore activation is detected and analysed by fluorescence imaging. Digital image correlation is used to measure the strain field ahead of the crack tip, whereas the corresponding stress field is calculated using the Hutchinson–Rice–Rosengren singularity field equations. Mechanophore activation follows a power law dependence on distance from the crack tip and provides both a qualitative and quantitative measure of the strain and stress fields ahead of the crack.

Self-healing in orthopedic bone cement is demonstrated with a novel thermoplastic solvent-bonding approach. Low toxicity solvent-filled microcapsules, embedded in a commercial acrylic bone cement matrix, enable recovery of up to 80% of the virgin fracture toughness of the cement at room and body temperature conditions without external stimuli or human intervention.

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Polymer-based components manufactured by stereolithography-based (SLA) three-dimensional (3D) printing tend to show relatively poor mechanical strength compared to polymer-based components fabricated by conventional methods such as compression molding. Some of this difference is related to the thermoset nature of typical SLA 3D-printed materials, where high cross-linking density and brittle material behavior can result in catastrophic material failure, limiting the life span of SLA 3D-printed composite materials. Previous studies have investigated potential techniques for improving the mechanical strength of SLA 3D-printed polymer components, such as the addition of various strengthening fillers; however, a few studies have investigated the incorporation of self-healing materials for SLA 3D printing to extend material lifetimes. In this study, we investigate the use of a microcapsule catalyst self-healing system in conjunction with commercially available photocurable resin toward increasing SLA 3D-printed specimen lifetime and material sustainability. Microcapsules filled with healing fluids are synthesized using in situ interfacial polymerization and dispersed in commercial resin prior to SLA 3D printing of self-healing composite specimens. The ability of these microcapsules to survive the SLA 3D printing process intact is demonstrated, and X-ray nano-computed tomography (X-ray Nano-CT) imaging shows microcapsules to be distributed throughout printed specimens. The self-healing behavior of these SLA 3D-printed composite materials is evaluated via quantification of mechanical properties, and healing efficiency. Overall, this is a facile and promising approach for the incorporation of self-healing behavior into SLA 3D printing resins.