Visual Appearance of Chiral Nematic Cellulose‐Based Photonic Films: Angular and Polarization Independent Color Response with a Twist

Hydroxypropyl cellulose (HPC) is a biocompatible cellulose derivative capable of self assembling into a lyotropic chiral nematic phase in aqueous solution. This liquid crystalline phase reflects right-handed circular polarized light of a specific color as a function of the HPC weight fraction. Here, we demonstrate that, by introducing a crosslinking agent, it is possible to drastically alter the visual appearance of the HPC mesophase in terms of the reflected color, the scattering distribution and the polarization response, resulting in an exceptional matte appearance in dry solid-state films. By exploiting the interplay between order and disorder, a robust and simple methodology towards the preparation of polarization and angular independent color was developed, which constitutes an important step towards the development of real-world photonic colorants.
This work is funded by EPSRC grant EP/R511675/1 to B.F.-P., S.V.; by EPSRC grant EP/L016087/1 to C.A.W.; by BBSRC David Phillips fellowship BB/K014617/1 to G.J., S.V.; by EU’s Horizon 2020 research and innovation programme under the Marie Skodowska-Curie grant agreement No. 722842 (ITN Plant-inspired Materials and Surfaces – PlaMatSu) to G.T.K., S.V.; by Swiss National Science Foundation #165176 to R.V.; by Croucher Cambridge International Scholarship to C.L.C.C.; by ERC grant ERC 2014 STG H2020 639088 to M.M.B., G.J., S.V.; by ERC grant ERC 2017 POC 790518 to R.M.P., S.V.