Elastomer films with strain-induced color change to detect functional failures

Unmet Need

Elastomers are polymer materials that can recover their original shape after being deformed. These materials, such as rubber or some plastics, are widely used in industrial and commercial applications in the automobile and packaging industries. While these materials are generally shape recovering and have prolonged shelf life, there are few methods that can detect when elastomers have been deformed beyond recovery and will not return to their original shape. These existing methods, like tensimeter or differential scanning calorimetry (DSC), rely on expensive and time-consuming equipment. Since these methods are costly and time consuming, failure is most commonly detected when the elastomer has reached critical failure. Thus, there is a need for rapid intuitive deformation detection methods to observe permanent deformation that can be easily incorporated into elastomer materials. Incorporation of failure detection into the material can prevent critical failures and encourage preventive maintenance.

Technology

Duke inventors have developed an elastomer film that changes color in response to permanent deformation. This is intended to be used instead of or in conjugation with existing elastomers to better identify when the material is approaching the failure point. Specifically, the film is composed of entangled polymers that exhibit color depending on the strain rate, or how quickly the material is being deformed. A mechanophore, a material that changes it’s physical or chemical properties in response to physical stimuli, is added to the material without compromising the strength of the elastomer. This mechanophore changes color (from colorless to blue/purple) when strain is applied, giving insight into how the chemical structure of the material is changing in response to strain and altering the user that failure is likely. The material is also recyclable, promoting sustainable and environmentally friendly business practices. This material allows precise detail to be collected about the structure of the film in real-time and would be ideal for any application where elastomers deform. This film has demonstrated the mechanochromic properties in the lab in response to varying strain and can detect strains up to 1000%.

Advantages

• Color change is consistent and noticeable, visibly changing from colorless to blue/purple
• The mechanochromic monomer can be added to most elastomers
• Further analysis of color change provides deeper insights to material failure
• The material is recyclable, supporting sustainable business practices