摘要
Despite the availability of elaborate varieties of nanoparticles, their assembly into regular superstructures and photonic materials remains challenging. Here we show how flexible films of stacked polymer nanoparticles can be directly assembled in a roll-to-roll process using a bending-induced oscillatory shear technique. For sub-micron spherical nanoparticles, this gives elastomeric photonic crystals termed polymer opals showing extremely strong tunable structural colour. With oscillatory strain amplitudes of 300%, crystallization initiates at the wall and develops quickly across the bulk within only five oscillations. The resulting structure of random hexagonal close-packed layers is improved by shearing bidirectionally, alternating between two in-plane directions. Our theoretical framework indicates how the reduction in shear viscosity with increasing order of each layer accounts for these results, even when diffusion is totally absent. This general principle of shear ordering in viscoelastic media opens the way to manufacturable photonic materials, and forms a generic tool for ordering nanoparticles.
赵其斌
副教授
我的研究关注软功能材料中的介观结构调控及其光学、热学与力学功能。我们以胶体、颗粒组装和聚合物复合体系为主要材料平台，研究剪切、弯曲、拉伸和循环形变等外部力学场如何驱动微结构重排、结晶、晶格转变与取向选择，并进一步调控材料的结构色、光谱响应、热辐射特性和力学响应。通过将软物质物理、可规模化加工和结构—性能分析相结合，研究旨在发展可编程软光子材料与功能涂层，为自适应光学表面、光热调控、传感和机械编码材料提供新的设计思路.