Synthetic Opals based on Block Copolymers

• Applicant: Professor Dr.-Ing. Markus Gallei
• Subject Area: Preparatory and Physical Chemistry of Polymers
• Term: from 2014 to 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 264750759

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.

• DFG Programme: Research Grants