Strain-Tunable
One Dimensional Photonic Crystals Based on Zirconium Dioxide/Slide-Ring
Elastomer Nanocomposites for Mechanochromic Sensing
- Publication date
- 2015
- Publisher
Abstract
We
demonstrate the fabrication and performance of tunable, elastic organic/inorganic
composite one-dimensional photonic crystals (1DPCs) in the visible
spectrum. By controlling the composition of high refractive index
metal oxide nanoparticle/polymer composites, a refractive index difference
of 0.18 between the filled and unfilled polymer layers can be achieved
while maintaining desirable flexibility and elasticity. This index
contrast is achieved with a loading of 70 wt % zirconium dioxide nanoparticles
within a slide-ring elastomer matrix, which is composed of topologically
cross-linked polyrotaxane polyols. The large refractive index contrast
enables high reflectivity while simultaneously minimizing the number
of layers necessary, compared to purely polymer systems. Because the
films are both flexible and elastic, these nanocomposite 1DPCs can
function as colorimetric strain sensors. We demonstrate the sensing
behavior of these 1DPCs by applying over 40% strain, resulting in
a visible color shift across the visible spectrum from red to blue.
1DPCs of just 6 periods maintain reflectance of 40% throughout the
visible spectrum, with a tensile mechanochromic sensitivity (Δλ/Δε<sub>max</sub>) as high as −6.05 nm/%