电场调控智能流体动态自组装及光传输特性研究

Amorphous photonic crystals (RPCs) fabricated by self-assembly processes can display photonic properties and have wide applications in tunable electro-optic devices and intelligent sensor. However, the majority of research on RPCs has been focused on incorporating stimulus-responsive materials into the self-assembled photonic crystal structures. Depending on the specific applications, the challenges in developing responsive photonic crystals include limited tunability of the band gap, a slow response to external stimuli, incomplete reversibility, and difficulty of integration into existing photonic devices. Based on electrorheology effect, we have preliminaryly found that the disordered dielectric structures formed through field-controlled reversible self-assembly of smart fluids manifest complete photonic properties without the above mentioned limitations. In order to elucidate the basic rules and the controllability of dynamic self-assembly and light propagation characteristics, we will design and fabricate a class of quasi-amorphous clusters through reversible self-assembly of external field modulated intelligent fluids. In this project, the dielectric nanoparticles with orientation interaction (through dielectric anisotropy by surface chemical modification) and specific photonic properties will be fabricated and dispersed in insulating liquid. Characteristics of dynamic self-assembly, disordered nanoclusters formation and their relationships with features of light propagation will be controlled by dynamic electric field and studied by both real-time observation technique and non-equilibrium system dynamics simulation. Based on these results, the modulation method on the reversible self-assembly of intelligent fluids will be developed. With successful accomplishing the goals, we’ll realize the regulation and quantitative forecasting of intelligent fluids self-assembly and light propagation with unified process. The simple, reversible and scalable process developed in this project may have a significant impact on eradicating the drawback of current responsive photonic crystal s and become the solid foundation for novel photonic devices and sensors.

智能流体在外场下形成的介稳态胶体纳米晶簇具有新颖的光学特性，在可调性光电元件和智能传感器中有广阔的应用前景。我们前期研究发现电场调控智能流体的自组装过程可形成完全可逆的动态自组装体系，不仅具有响应性光子晶体的光学特性，而且能有效解决调控范围窄、响应慢、难于集成等缺点。为进一步阐明场致智能流体动态自组装的本质规律和光传输特性，本项目结合极性分子型巨电流变材料在低电场下的空间位阻作用，以电场响应性非晶胶体结构为研究对象，设计并制备具有特定光学功能和表面定向相互作用的智能胶体颗粒；通过外加动态电场和实时观测研究短程有序胶体纳米晶簇的动态组装过程及新组装结构与光传输特性的关系；揭示智能流体定向、可逆自组装过程调控的新方法，实现外加电场对智能流体自组装过程和光传输功能的统一可逆调节与定量预测, 为构筑基于电场诱导胶体粒子动态结构的新型光子器件并阐明其光电作用机制奠定坚实的实验和理论基础。

基于光子晶体的全彩显示器件在新型被动显示(如电子书、电子纸、防伪)、健康检测和传感领域具有广泛的应用前景。但文献广泛报道的时变磁场调控技术还存在调控范围窄、响应速度慢和难于集成的缺点，需要开发新型的光子晶体调控技术。本项目以极性分子型智能流体材料在低电场下的空间位阻对非晶胶体结构调控机制为基础，设计并制备了具有电场响应和表面定向作用的单分散碳包覆磁性氧化铁(C@Fe3O4) 无机空心微球、PS@PANI高分子微球等智能胶体颗粒（100~300nm）分散体系；通过外加动态电场和实时观测等技术研究了短程有序胶体纳米晶簇的动态组装过程，发现胶体颗粒间的自组装过程受颗粒间电致作用力、智能流体流变特性及电场强度共同控制，进而给出了基于多层介质极化的Maxwell-Wagner模型和浓厚分散体系的Bruggeman-Hanai理论的短程有序胶体纳米晶簇的新型组装结构调控方法；通过优化智能流体的结构和流变特性，实现了在0~1.5V偏压和自然光下显色范围（色域）达到460nm~740nm的全彩色显示精确调控，响应时间可达到200ms以下。进一步针对电致组装多重结构色转换基本原理，我们在国际上首次将电化学沉积技术和“咖啡环”效应相结合，开发了基于弯液面限域3D打印的高精度图形化微电极、微开关成型新原理和新方法，实现了特征尺寸达到1微米以下的纳米晶铜线和PA12/CFs透明导电电极精确制备。基于此，我们设计了高饱和度全色显示像素、具有拉伸变色性能的单双面显色多重响应光子水凝胶、大角度和宽波长防眩光薄膜等原型器件，为进一步开发基于电场调控的被动显示器件、防伪标签及智能伪装材料等多个新兴应用提供了应用基础理论。.本研究已发表高水平学术论文21篇、会议论文1篇(SCI收录20篇)，在被动显示材料设计及其调控方面已形成3项核心发明专利(2项已授权)，在器件加工与测试方面形成9项辅助专利(6项已授权)，培养研究生8名。