A research team led by Prof. Suseok Choi from the Department of Electrical Engineering at POSTECH has been featured on the Back Cover of Advanced Functional Materials (Impact Factor 18.5) for their research on uniform stretchable control technology enabling encrypted polarization functionalities.

The study was conducted by Junhyuk Shin (Ph.D. candidate, first author), Hakjun Yang (Ph.D. candidate), Jiyun Park, and Sanghyun Han (Ph.D. candidate) under the supervision of Prof. Choi. The research demonstrates a technology that enables strain sensing as well as color and polarization separation functions in multi-pixel devices of next-generation stretchable smart materials through the development of uniform stretchable control technology.

Conventional stretchable electronic devices often suffer from unstable performance when implementing multi-pixel architectures or large-scale patterned designs, because the stretching deformation is not spatially uniform. This problem becomes particularly significant when using intrinsically stretchable materials, such as silicone or skin-like soft materials. As a result, many existing approaches rely on extrinsic stretchable structures, such as serpentine designs, which allow only limited stretching. This limitation has made it difficult to achieve technological advances toward multi-patterned and pixelated devices based on intrinsically stretchable materials.

To address this issue, the research team utilized mechanochromic color materials, a type of intrinsically stretchable material that can stretch like rubber and change color in response to mechanical deformation. Using this material, the team demonstrated for the first time a technique that allows precise measurement of multi-pixel deformation and uniform control of stretching behavior. In addition, external deformation-control strategies such as rigid-island and soft-substrate structures as well as kirigami patterns were applied to effectively resolve the problem of deformation imbalance. This work is expected to contribute to the advancement and broader impact of stretchable technologies based on intrinsically stretchable materials.

Furthermore, by applying uniform and flexible pattern control to multi-pixel arrays of chiral liquid crystal elastomers (CLCEs)—an intrinsically stretchable material with tunable optical polarization properties—the researchers demonstrated that strain-dependent color separation and circularly polarized light selectivity can be precisely controlled. This technology opens new possibilities for next-generation smart materials, including stretchable displays, security encryption devices, and wearable optical sensors, and is expected to be applicable to various fields that require dynamic control of color and polarization.

This research was supported by the Samsung Science and Technology Foundation and by the Stretchable Display Development Program and Stretchable Technology Demonstration Program funded by the Korea Evaluation Institute of Industrial Technology (KEIT).