More-sustainable approaches to produce effect pigments are being intensively searched [1] for to replace inorganic and synthetic polymer components by a group of researchers of the University of Cambridge (Department of Chemistry, Department of Engineering, Nanophotonics Centre – University of Cambridge, United Kingdom), with the objective to replace less sustainable materials.
A great attention in focused on self-assembly of cellulose nanocrystals that could produce structurally colored films. This can be a great potential candidate to produce more sustainable photonic pigments.
The challenge was to overcome the small-scale production. Restrictions on the rheological properties of the deposited viscoelastic material represented the main problems.
The optimization of the coating parameters affecting the self-assembly process permitted metre-scale structurally coloured films with tunable colour across the entire visible spectrum.
Furthermore, they [1] show that these structurally coloured films can be processed into vivid, water-stable photonic cellulose nanocrystals microparticles that can be used as a sustainable effect pigment or ‘glitter’ for a wide variety of applications.
Importantly, these particles retained their optical response after a year without fading or redispersing, even in water.
[1] Reference: “Large-scale fabrication of structurally coloured cellulose nanocrystal films and effect pigments.” Nature materials, 21, 352-358, 2022.
