透明光子晶体薄膜的力致变色调控及防伪应用

利用SiO2胶体粒子构筑三维蛋白石光子晶体阵列，并将其嵌入聚二甲基硅氧烷（PDMS）弹性体内，制备了一种具有力致变色性能的透明光子晶体薄膜。采用SEM、光纤光谱仪、数码相机等对光子晶体薄膜进行了结构、光学性能的表征，并研究了其在防伪中的应用。结果表明：施加拉力时，该透明光子晶体薄膜显现结构色，并随拉伸量的增加发生持续蓝移，撤销拉力可逆回复至初始状态，且即使经历100次循环拉伸，光子晶体薄膜依旧保持稳定的光学性能。将光子晶体薄膜进行图案化设计，通过施加或撤销拉力可使隐藏于其中的图案快速显现或消失，在防伪领域具有广阔的应用前景。

Mechanochromic Modulation and Anti-counterfeiting Application of Transparent Photonic Crystal Films

In this paper, a transparent photonic crystal film was designed with tunable mechanochromic properties. The monodispersed SiO2 colloids were self-assembled to form 3D opal photonic crystals and then embedded in elastomeric PDMS to generate the photonic crystal film. The structure and optical properties of photonic crystal films were characterized by SEM, fiber optical spectrometer and digital camera, and their applications in anti-counterfeiting was studied. The results showed that the transparent photonic crystal film exhibited an obvious structural color upon stretching, and the color experienced a continuous blue shift with the increase of tensile strain. Moreover, the photonic crystal film can back to its original state reversibly upon releasing. Even after 100 cycles of stretching and releasing, the photonic crystal film still maintained stable optical properties. Through the patterned design of the photonic crystal film, the hidden pattern of photonic crystal film could be revealed and disappeared quickly by applying or withdrawing the tension, which has broad application prospects in the field of anti-counterfeiting.