# Smart Plastics (DD-057) > In October 2022, chemists Adrian Rylski and Zachariah Page at the University of Texas at Austin reported in Science a way to make one polymer that is hard in some places and soft in others. They start with a liquid industrial monomer, cis-cyclooctene, and add two ruthenium catalysts. Where blue LED light shines, one catalyst switches on and builds trans-polyoctenamer, a stiff, opaque, semicrystalline plastic. In the dark, the other slowly builds cis-polyoctenamer, a soft, stretchy rubber. Because both regions are the same material, the boundary between them is seamless. The light sets the pattern while the plastic forms; it doesn't switch a finished part back and forth. - Department: Tech (also Science) - First published: 2025-06-11 - Last updated: 2025-06-11 - Permalink: https://detailenjoyer.com/case/smart-plastics/ - Author: Marcus Easterling (DetailEnjoyer), The Detail Department ## On the timeline - **Oct. 13, 2022**: UT Austin chemists publish light-patterned hard-and-soft polymers in Science Full timeline: https://detailenjoyer.com/timeline/?case=smart-plastics ## Quick facts - **DD-057-F01**: UT Austin's 'smart plastic' turns hard where blue light hits it and stays soft where it doesn't, because light controls which catalyst builds the polymer. _(Write-up · Exhibit B (One monomer, two catalysts))_ - **DD-057-F02**: The light-hardened regions are about 300 times stiffer than the soft ones, yet both are the same polymer. _(Write-up · Exhibit E (Why it matters))_ ## Write-up A plastic that blue light makes hard or soft. UT Austin chemists pattern rigid, crystalline zones into soft rubber as it forms. 1. **Who made it**: Adrian Rylski, Zachariah Page and colleagues at UT Austin published the method in Science on Oct. 13, 2022. Page called it 'the first material of its type'. 2. **One monomer, two catalysts**: The starting liquid is cis-cyclooctene, an industrial monomer. One ruthenium catalyst is activated by blue light (with a light-absorbing helper) and builds the trans form of the polymer; a second works slowly in the dark and builds the cis form. 3. **Light makes it hard**: Under about 5 minutes of blue LED light, around 90% of the monomer turns into trans-polyoctenamer: opaque, about 65% crystalline and stiff, with a modulus of roughly 800 to 1,000 MPa. 4. **Dark keeps it soft**: Left in the dark for about an hour, the mix becomes cis-polyoctenamer: transparent, only about 20% crystalline, and rubbery, with a modulus around 3 MPa and stretching to about 800% before breaking. 5. **Why it matters**: By shining light through a pattern, the team placed hard zones inside a soft matrix with seamless joints. UT says the material is 10 times as tough as natural rubber and sees uses in wearable electronics and soft robotics; it is still a lab result. ## Related case files - [Rapid Liquid Printing (RLP) (DD-013)](https://detailenjoyer.com/case/rapid-liquid-printing/): Another new way to shape soft materials, printing them inside a gel. - [Print Precision (DD-005)](https://detailenjoyer.com/case/print-precision/): Another way to put material exactly where it's wanted, one inkjet drop at a time. - [Shape Memory (DD-616)](https://detailenjoyer.com/case/shape-memory/): Another material whose properties are programmed - [Spray Foam Fun (DD-750)](https://detailenjoyer.com/case/spray-foam-fun/): Another polymer whose properties depend on how it's made: one plastic, hard or soft depending on light. ## Reel vs. record - **Confirmed**: UT Austin chemists (Rylski, Page and colleagues) made a polymer that comes out hard where blue LED light and a catalyst act, and soft elsewhere. It was published in Science on Oct. 13, 2022. [Science; UT News] - **Clarified**: it doesn't 'transition' from soft to hard on demand. Light decides the pattern while the liquid monomer polymerizes; a finished part isn't switched back and forth. [Science; Nature Materials] - **Misattributed**: '10x tougher than natural rubber' comes from UT's description of the material. In the paper, the fracture-toughness tests highlight the soft, stretchy form, not the rigid crystalline regions. [UT News; Science] - **Missing detail**: there are two catalysts. A light-activated one makes the stiff trans polymer; a second, slower one makes the soft cis polymer in the dark. [Science; Nature Materials] - **Context**: 'similar to common plastics' is roughly right. The polymer is a polyolefin, and UT compares it to the polymer in the most common plastic. It's a lab result, not yet a product. [UT News; Nature Materials] ## Video: Smart Plastics: A Plastic That Blue Light Makes Hard or Soft - Duration: 23.3 s · Published: 2025-06-11 - File: https://detailenjoyer.com/assets/videos/DKx_xQ-xpuh.mp4 ### Transcript DID YOU KNOW? Smart plastics represent a breakthrough in material science, transitioning from soft to hard under visible light. Developed by chemists at the University of Texas at Austin, these plastics start as monomers, small molecules that form polymers similar to common plastics. When exposed to blue LED light and a catalyst, illuminated areas crystallize into a rigid, semicrystalline structure 10x tougher than natural rubber. NOW YOU KNOW! ## Questions & answers **Q: Which university developed the light-patterned plastic?** A: It was published in Science in 2022. _(Source: Write-up · Exhibit A (Who made it) · Rylski et al., Polymeric multimaterials by photochemical patterning of crystallinity (Science, 2022); 'Smart Plastic' Material is Step Forward Toward Soft, Flexible Robotics and Electronics (UT News, 2022))_ **Q: What starting monomer did the team use?** A: It's an industrial monomer. _(Source: Write-up · Exhibit B (One monomer, two catalysts) · Rylski et al., Polymeric multimaterials by photochemical patterning of crystallinity (Science, 2022); Composites from photo-stereochemical patterning (Nature Materials, News & Views, 2023))_ **Q: What color of light switches on the hard-making catalyst?** A: Inexpensive blue LEDs were used. _(Source: Write-up · Exhibit C (Light makes it hard) · Rylski et al., Polymeric multimaterials by photochemical patterning of crystallinity (Science, 2022); Composites from photo-stereochemical patterning (Nature Materials, News & Views, 2023))_ **Q: What does the mix become in the dark?** A: It stretches to about 800% before breaking. _(Source: Write-up · Exhibit D (Dark keeps it soft) · Rylski et al., Polymeric multimaterials by photochemical patterning of crystallinity (Science, 2022); Composites from photo-stereochemical patterning (Nature Materials, News & Views, 2023))_ **Q: What uses does UT see for the material?** A: It is still a lab result. _(Source: Write-up · Exhibit E (Why it matters) · 'Smart Plastic' Material is Step Forward Toward Soft, Flexible Robotics and Electronics (UT News, 2022); Composites from photo-stereochemical patterning (Nature Materials, News & Views, 2023))_ ## Sources - [Rylski et al., Polymeric multimaterials by photochemical patterning of crystallinity (Science, 2022)](https://doi.org/10.1126/science.add6975) - ['Smart Plastic' Material is Step Forward Toward Soft, Flexible Robotics and Electronics (UT News, 2022)](https://news.utexas.edu/2022/10/13/smart-plastic-material-is-step-forward-toward-soft-flexible-robotics-and-electronics/) - [Composites from photo-stereochemical patterning (Nature Materials, News & Views, 2023)](https://www.nature.com/articles/s41563-022-01456-2) ## Cite this case file Easterling, Marcus. "Smart Plastics." The Detail Department (DetailEnjoyer), case file DD-057, last updated Jun 11, 2025. https://detailenjoyer.com/case/smart-plastics/