Influence of the thermodynamic phase during polymerization and embedded hexagonal boron nitride nanoflakes on a polymer network liquid crystal

Abstract

Devices that control the near-infrared light through basic architectural concepts as well as having external field tunability are much sought-after particularly for energy-saving applications. A judicious combination of the polymer content serving as a matrix and the liquid crystal as the active substance appears to be well-suited for the purpose. Recently, we demonstrated that with a proper choice of the architecture and spatial placement of 2D material nanostructures, it is possible to build such devices entirely from IR-transparent components. While we previously focussed on systems polymerized in the liquid crystalline nematic phase, the present article brings out the difference in the outcome when the polymerization is carried out in the liquid isotropic phase. Polarized optical and scanning electron microscopy studies show that addition of hexagonal boron nitride nanoflakes changes the morphology from a loose bead-like network to a distinct porous/droplet structure with interconnected beads. Haze measurements, which are of paramount importance for devices based on scattering of light, bring out quite well the influences of the phase in which polymerization was done and the inclusion of the nanoflakes. Dielectric, calorimetric are also reported to further delineate the distinction among differently polymerized systems.