This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Polymeric materials, such as plastics and rubbers, are essential in everyday life. However, detecting where mechanical stress is concentrated inside them remains a challenge.
Materials that can visibly indicate stress or damage could help improve the safety, reliability and life span of polymer-based products. This has driven growing interest in mechanoresponsive materials that change their optical properties when subjected to mechanical force. A research team at the Institute of Science Tokyo (Science Tokyo) in Japan, led by Professor Hideyuki Otsuka, along with Dr.
Kuniaki Ishizuki and assistant professor Akira Takahashi, developed a simple post-synthetic strategy for adding stress-responsive fluorescence to an existing polymer. Their study, published in the journal Advanced Materials on Aug. 17, 2026, demonstrates that blending a mechanophore-containing polymer with styrene–butadiene–styrene (SBS) block copolymer can produce reversible fluorescence when the material is stretched without chemically modifying the original polymer. Conventional mechanoresponsive polymers typically require mechanophores, which are mechanically responsive molecular units.
These are incorporated directly into the polymer during synthesis. But while this approach enables precise control over the material's response, it may require complex synthesis pathways and may not be readily applicable to widely used polymers. Finding different ways to introduce mechanoresponsive functionality after synthesis could therefore make these smart materials easier to develop and use.
The researchers addressed this challenge by taking advantage of the microphase-separated structure naturally formed by SBS. SBS is a block copolymer, a type of polymer made by joining different polymer segments into distinct blocks. SBS contains rigid polystyrene (PS) domains dispersed within softer polybutadiene domains, giving the material both hard and flexible regions.
The team synthesized PS containing a tetraarylsuccinonitrile (TASN) mechanophore and blended it with commercially available SBS. Because the added polymer has the same chemical composition as the PS domains in SBS, it selectively localizes within these rigid PS regions through microphase separation. This arrangement allows mechanical stress to be efficiently transferred from the surrounding polymer to the mechanophores without chemically altering the host material.
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