Transparent Polymer Opal Thin Films with Intense UV Structural Color

Abstract

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.

Dial-In Synthesis of ‘Polymer Opal’ Core–Interlayer–Shell Composite Nanoparticles

“…100 nm diameter) cores with those developed from a typical synthesis endpoint (ca. 300 nm diameter).These illustrate the successful control of particle (spherical) shape integrity and polydispersity at the beginning and endpoint of core growth, strongly confirming the observations reported in the literature reported by the authors [65,66] and by others [9,25], as well as the overall robustness of the synthesis methodology. The measured PDI, as inferred from the standard deviation in sizes, was in the range of 0.05 to 0.10 in these analyses, which was slightly above that as determined by DLS; however, there were far fewer counted particles (n < 50), giving a likely higher statistical error.…”

“…This research demonstrates how it is possible to grow PO cores under a range of conditions with multiple routes to obtaining a given particle size. An overview of this is given in Table 3, where the time taken to obtain the core size need for the specified resultant color appearance as indicated by the literature is reported [66][67][68]. This is as determined from Figure 5, where these times are extrapolated from the exponential fit curves.…”

High-Angle Structural Color Scattering Features from Polymeric Photonic Structures

“…The end result is rubbery, free-standing films displayin intense structural color which changes with viewing angle and illumination, picture rightmost in Figure 1a. With the resulting peak wavelength of color appearanc dependent on the CIS particle diameter, this process has previously been tuned t engineer POs reflecting in the UV [33] through to red [21] and near-infrared part of th spectrum. Structural order is seen to iteratively improve and permeate into the films with further shear as the PS cores self-assemble within the PEA matrix.…”