Nanoscale hyperspectral imaging of tilted cholesteric liquid crystal structures

Abstract

In tilted cholesteric liquid crystals, hyperspectral imaging reveals the correlation between the bandgap spectral properties and spatial twists.

Hyperspectral Imaging of Bio-Inspired Tilted Cholesteric Liquid Crystal Structures

“…The signature resides in the fine tuning of the spectral characteristics of the bandgap into the part of a polygon in which the orientation of the helix axis is spatially changing. A correlation between spatial changes and spectral changes on a mesoscopic scale is therefore made possible [4]. These results demonstrate the interest of hyperspectral imaging for the precise study of complex cholesteric components, also existing in biological samples.…”

Biomimetic design of iridescent insect cuticles with tailored, self-organized cholesteric patterns

“…In the mid-1990s, polygonal textures in the film plane and in cross sections were observed via TEM 48 and AFM 49,50 . In the 2010s, investigations of polygonal textures focused on glass-forming oligomers [51][52][53][54][55][56][57] such as those used in the present study, which does not focus on the polygonal texture itself.…”

Biomimicry of iridescent, patterned insect cuticles: comparison of biological and synthetic, cholesteric microcells using hyperspectral imaging

“…This advanced instrument is thus a powerful tool for the analysis of textures for which the spectral response is conditioned by the spatial organization, as is the case with chiral molecular arrangements. 43,49 In this section, we compare the hyperspectral response of a cholesteric synthetic sample bearing a polygonal texture with that of the cuticle considered to be similar or analogous to it, namely, the microcells of the green band of C. gloriosa. The synthetic sample is referred to as PG30, and more information on its preparation is provided in section 2.…”

“…The overall question is to what extent these synthetic textures are precisely comparable to the biological assemblies of microcells. Most optical and structural investigations on the cholesteric polygonal texture [36][37][38][39][40][41][42][43][44] have focused on polysiloxane-based oligomers such as those of the present study (figure 3). Atomic force microscopy (AFM) reveals a cone shape of the polygonal cells, which are the locus of the double-spiral patterns (figure 2b).…”