Transparent Polymer Opal Thin Films with Intense UV Structural Color

• Published in: Molecules (Basel, Switzerland) Vol. 27; no. 12; p. 3774
• Main Authors: Rosetta, Giselle, Gunn, Matthew, Tomes, John J., Butters, Mike, Pieschel, Jens, Hartmann, Frank, Gallei, Markus, Finlayson, Chris E.
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 11-06-2022; MDPI
• Subjects: Anisotropy; Color; Color vision; Composite materials; Cones; Crystal structure; Crystals; Emulsion polymerization; Mechanical properties; optical characterization; Optical properties; Particle size; Photobleaching; Photonic crystals; Photovoltaics; Polymer matrix composites; Polymers; Refractivity; Scattering; thin film coatings; Thin films; UV reflecting films; UV spectroscopy; Viewing
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules27123774

We report on shear-ordered polymer photonic crystals demonstrating intense structural color with a photonic bandgap at 270 nm. Our work examines this UV structural color, originating from a low refractive index contrast polymer composite system as a function of the viewing angle. We report extensive characterization of the angle-dependent nature of this color in the form of ‘scattering cones’, which showed strong reflectivity in the 275–315 nm range. The viewing range of the scattering was fully quantified for a number of planes and angles, and we additionally discuss the unique spectral anisotropy observed in these structures. Such films could serve as low-cost UV reflection coatings with applications in photovoltaics due to the fact of their non-photobleaching and robust mechanical behavior in addition to their favorable optical properties.