Professor Zhou Qitao of Xia fan research group realized multimodal and covert–overt convertible mechanical stress sensitive structural color materials

Professor Zhou Qitao of Xia fan research group realized multimodal and covert–overt convertible mechanical stress sensitive structural color materials

Structural color materials that can realize color transformation response to external stimuli have a wide application potential in the fields of anti-counterfeiting and sensing. However, most of the current stimulus responsive structural color materials can only change between different colors, and it is difficult to realize the transformation between transparent state and color state.

Recently, Professor Zhou Qitao of Professor Xia fan's research group at China University of Geosciences (Wuhan) and his collaborators developed a composite laminate of soft poly(dimethylsiloxane) (PDMS) with a rigid SiO2-nanoparticle (NP) structure pattern is developed as a multidimensional structural color platform. Owing to the similarity in the optical properties of PDMS and SiO2 NPs, this device is fully transparent in the normal state. However, as their mechanical strengths differ considerably, upon compressive loading, a buckling-type instability arises on the surface of the laminate, leading to the generation of 1D or 2D wrinkled patterns in the form of gratings. Finally, an application of the device in which quick response codes are displayed or hidden as covert–overt convertible colored patterns for optical encryption/decryption, showing their remarkable potential for anticounterfeiting applications.

Figure 1. stress sensitive structural color materials.

This work was published on Advanced Materials with the title of "Multimodal and covert – overt convertible structural decoration transformed by mechanical stress".

The research was supported by the National Natural Science Foundation of China. Professor Taesung Kim of Ulsan National Institute of Science and Technology and Professor Kyungjun Song of Busan National University are the corresponding authors of the work. The first author is Professor Zhou Qitao of China University of Geosciences (Wuhan).

Article link: https://doi.org/10.1002/adma.202001467