Synthetic Opals based on Block Copolymers

嵌段共聚物由于其固有的在10-100纳米范围内形成高度有序结构的能力而引起了广泛的关注。近年来，人们还研究了它们作为光子带隙材料的可用性。与普通染料相比，这些材料具有所谓的结构色。在这个项目中，基于超高分子量（UHMW）嵌段共聚物的三维（3D）光子材料具有高度有序的球形畴和高周期性。通过使用活阴离子聚合协议，将提供由弹性体和热塑性段组成的定义良好的UHMW嵌段共聚物。通过类似聚合物的反应以及均聚物和功能化单分散纳米颗粒的共混，球形结构域将在尺寸和折射率对比方面得到进一步改进。在这个项目中，具有球形形态的嵌段共聚物将成为重点。因此，可以在传输中测量结构颜色，以利用全光子带隙特性。这些新材料的自组装技术和微相分离将被研究，以保证在几微米的长度尺度上的高域有序。此外，畴选择性交联反应将提供完全可逆的机械行为，并伴有反射/透射颜色变化。这些材料是新型传感器应用或显示技术的有希望的候选者。该项目的研究将提供对（部分交联的）UHMW嵌段共聚物的基本理解，这些共聚物有可能用作3D光子带隙材料。

Block copolymers attract enormous attention due to their intrinsic capability to form highly ordered structures in the range of 10-100 nanometers. In recent years, also their usability as photonic band gap materials was studied. Compared to common dyes, these materials feature so-called structural colours. Within this project, three-dimensional (3D) photonic materials based on ultrahigh molecular weight (UHMW) block copolymers featuring highly-ordered spherical domains and a high periodicity are investigated. Access to well-defined UHMW block copolymers consisting of elastomeric and thermoplastic segments will be provided by using living anionic polymerization protocols. Spherical domains will be further modified in terms of size and refractive index contrast by polymer-analogous reactions as well as blending with homopolymers and functionalized monodisperse nanoparticles. Within this project, explicitly block copolymers with spherical morphology will be in focus. Hence, structural colours can be measured in transmission in order to take advantage of full photonic band gap properties. Self-assembly techniques and microphase separation of these novel materials will be investigated in order to guarantee a high domain ordering on the length scale of several microns. Furthermore, domain-selective cross-linking reactions will provide a fully reversible mechanical behaviour accompanied with reflection/transmission colour changes. These materials are promising candidates for novel sensor applications or in display technologies. The research within this projection will provide access to fundamental understanding of (partially cross-linked) UHMW block copolymers for potential use as 3D photonic band gap materials.