Zhou Qitao, Park Jun Gyu, Bae Juyeol, Ha Dogyeong, Park Jungyul, Song Kyungjun, Kim Taesung
Department of Mechanical Engineering, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Ulsan, 44919, Republic of Korea.
Engineering Research Center of Nano-Geomaterials of the Ministry of Education, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan, 430074, China.
Adv Mater. 2020 Jun;32(25):e2001467. doi: 10.1002/adma.202001467. Epub 2020 May 8.
Most materials and devices with structurally switchable color features responsive to external stimuli can actively and flexibly display various colors. However, realizing covert-overt transformation behavior, especially switching between transparent and colored states, is more challenging. A composite laminate of soft poly(dimethylsiloxane) (PDMS) with a rigid SiO -nanoparticle (NP) structure pattern is developed as a multidimensional structural color platform. Owing to the similarity in the optical properties of PDMS and SiO 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, is demonstrated.
大多数具有响应外部刺激而结构可切换颜色特征的材料和器件能够主动且灵活地显示各种颜色。然而，实现隐蔽 - 公开的转变行为，尤其是在透明和有色状态之间切换，更具挑战性。一种具有刚性SiO₂纳米颗粒（NP）结构图案的软质聚二甲基硅氧烷（PDMS）复合层压板被开发为多维结构颜色平台。由于PDMS和SiO₂ NPs在光学性质上的相似性，该器件在正常状态下是完全透明的。然而，由于它们的机械强度差异很大，在压缩载荷作用下，层压板表面会出现屈曲型不稳定性，导致以光栅形式产生一维或二维皱纹图案。最后，展示了该器件的一种应用，即快速响应码作为隐蔽 - 公开可转换的彩色图案用于光学加密/解密显示或隐藏，显示出它们在防伪应用中的巨大潜力。
