Versatile Mechanochromic Sensor based on Highly Stretchable Chiral Liquid Crystalline Elastomer

A mechanochromic strain sensor that is capable of distinguishing the orientation, the location, and the degree of deformation based on the highly stretchable membrane of main-chain chiral liquid crystalline elastomer (MCLCE) is proposed. The MCLCE film is designed to exhibit uniform and significant color shift upon the small strain by using step-growth polymerization of liquid crystal (LC) oligomer and its phase-stabilization in solvent mesogen. As conformally placed on the bottom elastomer sheet, the MCLCE film shows multimodal, instantaneous color change for sensing arbitrary in-plane deformation, out-of-plane bending, and nonzero Gaussian deformation. Based on high freedom in the device design, it is also demonstrated that this sensor can display color patterns or encrypted images in response to the localized weight or strain. The simple and straightforward concept proposed here can be applicable in the fields of wearable devices, displays, and soft robotics.

Automated summary

A novel mechanochromic strain sensor is proposed, which can distinguish the orientation, location, and degree of deformation based on a highly stretchable membrane of main-chain chiral liquid crystalline elastomer (MCLCE). By utilizing step-growth polymerization and phase-stabilization, the MCLCE film exhibits uniform and significant color shift upon small strain. The sensor shows multimodal, instantaneous color change for sensing arbitrary in-plane deformation, out-of-plane bending, and nonzero Gaussian deformation, and can also display color patterns or encrypted images in response to localized weight or strain.