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Large-scale fabrication of structurally coloured cellulose nanocrystal films and effect pigments


Cellulose nanocrystals are renewable plant-based colloidal particles capable of forming photonic films by solvent-evaporation-driven self-assembly. So far, the cellulose nanocrystal self-assembly process has been studied only at a small scale, neglecting the limitations and challenges posed by the continuous deposition processes that are required to exploit this sustainable material in an industrial context. Here, we addressed these limitations by using roll-to-roll deposition to produce large-area photonic films, which required optimization of the formulation of the cellulose nanocrystal suspension and the deposition and drying conditions. Furthermore, we showed how metre-long structurally coloured films can be processed into effect pigments and glitters that are dispersible, even in water-based formulations. These promising effect pigments are an industrially relevant cellulose-based alternative to current products that are either micro-polluting (for example, non-biodegradable microplastic glitters) or based on carcinogenic, unsustainable or unethically sourced compounds (for example, titania or mica).

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Fig. 1: Overview of the R2R processing of a CNC suspension into photonic films and microparticles.
Fig. 2: Film thickness and optical properties versus coating parameters.
Fig. 3: Effect of sonication and drying conditions on the visual appearance of blade-cast CNC films.
Fig. 4: Optical properties of CNC films cast by R2R and dried either statically or with stepwise continuous translation through an in-line hot air dryer.
Fig. 5: Photonic CNC microparticles.

Data availability

Additional data relating to this publication are available from the University of Cambridge data repository (


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This work was supported by the Engineering and Physical Sciences Research Council (EP/R511675/1 for S.V.; EP/N016920/1 for H.-L.L, J.J.B., M.D.V. and S.V.), by the European Union’s Horizon 2020 Marie Skłodowska-Curie research and innovation programme (H2020-MSCA-ITN-2016 722842 for B.E.D and S.V.) and the European Research Council (ERC-2014-STG H2020 639088 for B.F.-P., R.M.P. and S.V.; ERC-2017-POC 790518 for S.V.). We thank F. Firth for performing the thermogravimetric analysis characterization.

Author information

Authors and Affiliations



The concept of R2R-manufactured photonics was conceived by J.J.B., M.D.V. and S.V.; CNC suspensions, films and particles were prepared and characterized by B.E.D.; R2R experiments were realized by B.E.D. and H.-L.L.; B.F.-P and R.M.P. provided critical feedback on results. The manuscript was written by B.E.D., R.M.P., B.F.-P. and S.V. with input from all authors.

Corresponding author

Correspondence to Silvia Vignolini.

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Competing interests

The authors declare no competing interests.

Additional information

Peer review information Nature Materials thanks Jay Guo and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Supplementary Information

Supplementary Figs. 1–24 and Tables 1 and 2.

Supplementary Video 1

This time-lapse video shows a CNC film drying on a thin R2R web (75 µm), where the stress-induced web warping is clearly visible.

Supplementary Video 2

This time-lapse video shows a CNC film drying on a thick R2R web (500 + 75 µm), where no stress-induced web warping occurs.

Supplementary Video 3

This video shows the drying of a R2R-coated CNC suspension into a structurally coloured film, with the help of a hot air dryer placed in-line and blowing hot air at ~60 °C. The continuous deposition is performed stepwise, with the web being moved every 15 min by ~20 cm at a speed of vc = 0.1 m min–1.

Supplementary Video 4

This time-lapse video shows the in-line peeling of a thick CNC film.

Supplementary Video 5

This video shows a CNC particle initially observed in air being placed in a 1:1 mixture of ethanol and water. The redshift is progressive as ethanol preferentially evaporates and moisture condensation occurs. When no solvent is left, the particle dries and returns to its original colour in air. The video was accelerated six times compared to the original.

Supplementary Video 6

This video shows the samples of Fig. 1j in motion after turning the vials upside-down.

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Droguet, B.E., Liang, HL., Frka-Petesic, B. et al. Large-scale fabrication of structurally coloured cellulose nanocrystal films and effect pigments. Nat. Mater. 21, 352–358 (2022).

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