6533b824fe1ef96bd127fdf6

RESEARCH PRODUCT

Tuning the Properties of Photonic Films from Polymer Beads by Chemistry

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description

This paper describes the preparation of monodisperse colloids from various methacrylates. These colloids sediment well on glass slides and formin the dried statelarge three-dimensional face-centered cubic photonic crystal films with Bragg reflection in the visible region. Depending on crystallization conditions, the domain sizes vary between 50 and 300 μm. By cross-linking the polymer within the colloids, it is possible to increase the thermal stability of the polymeric photonic structure tremendously (up to 1 h at 200 °C). These photonic structures soften above Tg (rubbery photonic structure), but they cannot fuse. Cross-linked colloids from poly(tert-butyl methacrylate) can either thermally or chemically be modified. During thermal treatment (above 200 °C) the colloids shrink, as isobutene is split off. This allows a change of the lattice constant and the reflection color of an already crystallized dry photonic film. The acid-catalyzed cleavage of the ester bond allows the conversion of existing photoni...