发展识别便捷、加密隐蔽且具有多重防伪功能的光学复合材料对推动高端防伪技术进步、有效打击假冒伪造和保障国家经济安全具有重要意义。本项目设计了兼具彩色3D全息图像裸眼识别和多颜色上转换加密功能的新型聚合物纳米复合材料。采用水热法合成晶型结构、晶体尺寸及发光颜色可调的镧系离子掺杂上转换纳米晶，通过硅烷化和硫醇-烯烃点击反应在其表面分别引入硫醇、液晶基元和聚乙二醇甲醚。然后将修饰过的上转换纳米晶与硫醇-烯丙基醚-丙烯酸酯复合单体及液晶混合得到均匀分散液。在相干激光下，分散液通过光聚合诱导相分离，制得结构有序的光聚合物/液晶/上转换纳米晶全息复合材料，实现全息图像存储及上转换加密。进一步采用近红外光辐照以产生特定波长发光实现解密。通过上述研究，揭示上转换纳米晶对全息图像存储质量的影响规律，阐明多颜色上转换加密的分辨率对复合材料相分离程度的依赖关系，为发展先进防伪技术和建立有序复合新方法提供基础理论。

The development of optical composites with multiple anti-counterfeiting functions which are able to be easily identified while covertly encrypted, is of essential significance to accelerate the advance of high-end anti-counterfeiting techniques, to efficiently defeat the forgery, and to secure the national economy. In this proposal, novel polymer nanocomposites are designed with concurrent functions of colored 3D holographic images identifiable to the naked-eye and multicolor upconversion encryption. First, lanthanide ion doped upconversion nanocrystals (UCNC), with tunable crystal phases, crystal sizes and luminescence colors, will be synthesized via the hydrothermal technique. Subsequently, these UCNC are going to be surface treated via silanization and thiol-ene click reaction, offering three types of surface-functionalized UCNC, i.e., thiol, mesogenic unit and poly(ethylene glycol) methyl ether functionalized UCNC, respectively. Following, uniform dispersions will be formed by adding the surface-functionalized UCNC into the homogeneous mixtures composed of thiol-allyl ether-acrylate hybrid monomers and liquid crystals. Upon exposure of these dispersions to laser interference patterns, photopolymer/liquid crystal/UCNC holographic composites in ordered structure will be formed. During this process, simultaneous holographic image storage and upconversion encryption are going to be implemented. In addition, the decryption is able to be easily implemented by taking advantage of the specific upconversion luminescence when exposed to near-infrared light. Based on above research, the influence of UCNC on the recorded image quality and the dependence of upconversion encryption resolution on the composite segregation degree are also expected to be depicted. This novel paradigm proposed herein is envisioned to afford basic theories to the development of advanced anti-counterfeiting protocols and the construction of ordered polymer nanocomposites.