# Self-healing polymers: four ways to close a crack

> A timeline drawn along one crack that closes from left to right. Microcapsules of healing agent mend a crack once, thermally re-mendable links mend it many times with heat, a microvascular network delivers agent again and again, and a hydrogen-bonded rubber heals at room temperature when the cut faces are pressed together.

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- Open in the LabCanvas editor (LabCanvas account): https://www.labcanvas.com/editor.html?template=self-healing-polymers-four-ways-to-close-a-crack
- Updated: 2026-10-14
- Category: Materials graphical abstracts
- Method: Graphical abstract
- Starting materials: A cracked polymer or polymer composite
- Product: A polymer whose crack faces bond again, once (extrinsic, capsules) or many times (vascular, reversible covalent or hydrogen-bonded)
- Key result: Up to 75% toughness recovery (White et al. 2001); ~30% of linkages open above 120 °C (Chen et al. 2002); extensibility up to several hundred per cent after healing (Cordier et al. 2008)
- Figure: 1920 × 1080 px, 159 editable layers (2 generated objects with settings)

## Steps

1. **2001 · microcapsules**: A crack breaks capsules of healing agent; an embedded catalyst polymerizes it and bonds the faces; up to 75% of the toughness comes back (White et al. 2001), but only once at a given site (Toohey et al. 2007)
2. **2002 · re-mendable links**: Above 120 °C about 30% of the linkages disconnect and they reconnect on cooling, so a fracture can be mended many times without a catalyst (Chen et al. 2002)
3. **2007 · microvascular network**: A 3D microvascular network in the substrate delivers healing agent to cracks in an epoxy coating, which heal repeatedly (Toohey et al. 2007)
4. **2008 · hydrogen-bonded rubber**: Molecules from fatty acids and urea form chains and cross-links through hydrogen bonds; cut pieces pressed together heal at room temperature, again and again, and stretch several hundred per cent (Cordier et al. 2008)

## Uses

- Graphical abstracts on self-healing polymers and composites
- Talks comparing extrinsic and intrinsic healing
- Teaching dynamic bonds and damage repair

## References

1. White et al., “Autonomic healing of polymer composites”, Nature 2001. https://doi.org/10.1038/35057232 (method origin)
2. Chen et al., “A thermally re-mendable cross-linked polymeric material”, Science 2002. https://doi.org/10.1126/science.1065879 (primary)
3. Toohey, Sottos, Lewis, Moore & White, “Self-healing materials with microvascular networks”, Nat. Mater. 2007. https://doi.org/10.1038/nmat1934 (primary)
4. Cordier, Tournilhac, Soulié-Ziakovic & Leibler, “Self-healing and thermoreversible rubber from supramolecular assembly”, Nature 2008. https://doi.org/10.1038/nature06669 (primary)
5. Khan, “Self-healing dental biomaterials: bioinspired pathways to sustainable dentistry”, Biomater. Investig. Dent. 2025. https://doi.org/10.2340/biid.v12.45229 (review)

Credit: Drawn by LabCanvas after White et al., Nature 2001 (doi:10.1038/35057232); Chen et al., Science 2002 (doi:10.1126/science.1065879); Toohey et al., Nat. Mater. 2007 (doi:10.1038/nmat1934) and Cordier et al., Nature 2008 (doi:10.1038/nature06669).

## Questions

**What does the “Self-healing polymers: four ways to close a crack” template show?** A timeline drawn along one crack that closes from left to right. Microcapsules of healing agent mend a crack once, thermally re-mendable links mend it many times with heat, a microvascular network delivers agent again and again, and a hydrogen-bonded rubber heals at room temperature when the cut faces are pressed together.

**What are the steps shown in “Self-healing polymers: four ways to close a crack”?** 1. 2001 · microcapsules: A crack breaks capsules of healing agent; an embedded catalyst polymerizes it and bonds the faces; up to 75% of the toughness comes back (White et al. 2001), but only once at a given site (Toohey et al. 2007). 2. 2002 · re-mendable links: Above 120 °C about 30% of the linkages disconnect and they reconnect on cooling, so a fracture can be mended many times without a catalyst (Chen et al. 2002). 3. 2007 · microvascular network: A 3D microvascular network in the substrate delivers healing agent to cracks in an epoxy coating, which heal repeatedly (Toohey et al. 2007). 4. 2008 · hydrogen-bonded rubber: Molecules from fatty acids and urea form chains and cross-links through hydrogen bonds; cut pieces pressed together heal at room temperature, again and again, and stretch several hundred per cent (Cordier et al. 2008).

**What are the starting materials and the product?** Starting materials: A cracked polymer or polymer composite. Product: A polymer whose crack faces bond again, once (extrinsic, capsules) or many times (vascular, reversible covalent or hydrogen-bonded).

**Which papers is “Self-healing polymers: four ways to close a crack” based on?** White et al., “Autonomic healing of polymer composites”, Nature 2001 (doi:10.1038/35057232); Chen et al., “A thermally re-mendable cross-linked polymeric material”, Science 2002 (doi:10.1126/science.1065879); Toohey, Sottos, Lewis, Moore & White, “Self-healing materials with microvascular networks”, Nat. Mater. 2007 (doi:10.1038/nmat1934); Cordier, Tournilhac, Soulié-Ziakovic & Leibler, “Self-healing and thermoreversible rubber from supramolecular assembly”, Nature 2008 (doi:10.1038/nature06669); Khan, “Self-healing dental biomaterials: bioinspired pathways to sustainable dentistry”, Biomater. Investig. Dent. 2025 (doi:10.2340/biid.v12.45229).

**Can I edit the “Self-healing polymers: four ways to close a crack” template?** Yes. Open it in the LabCanvas editor: all 159 layers are editable, including 2 generated objects (structures, plots, equipment) with their own settings. Change the text, colours and layout, then export PNG, TIFF, SVG or PDF.

**Do I need an account to use this template?** Not to view it here. To open and edit it, sign in to LabCanvas or create a free account (the free plan keeps up to 3 designs). Downloading the figure is part of LabCanvas Pro (US$19 a month or US$199 a year).