Electrospun materials with high reflectance and polarization contrast for sensing applications in the mid-infrared atmospheric window

Abstract

Several applications in remote sensing and thermal management require materials with high reflectivity and polarization contrast in the mid-infrared (MIR) spectral range. However, the existing options often fall short in terms of mechanical properties and practicality, especially for field deployment. To address this challenge, we leverage the polaritonic response of poly(oxymethylene) (POM) and the anisotropy induced by electrospinning to produce robust POM fiber mats with high reflectance and polarization contrast in the MIR atmospheric window. Specular reflection IR spectroscopy demonstrates that the optical properties can be optimized by a series of mat post-treatments, namely submersion with a nonsolvent, incorporation of an index-matching medium, drawing, and compression, which were applied iteratively to refine the optical response. The optimized mats achieve a maximum reflectance of 60 ± 8% and a corresponding polarization contrast (degree of linear polarization) of 0.52 ± 0.01. Importantly, the formulated materials remain flexible and generally retain appropriate optical properties under long-term storage and when exposed to harsh simulated operational conditions. As a result, they are considered promising target substrates for the development, testing, and field deployment of advanced MIR polarimetric remote sensors.