Printing of Responsive Photonic Cellulose Nanocrystal Micro-Film Arrays

Change log

Interactive materials capable of changing appearance upon exposure to external stimuli, such as photonic inks, are generally difficult to achieve on a large scale as they often require self-assembly processes that are difficult to control macroscopically. Here we overcome this problem by preparing arrays of cellulose nanocrystal (CNC) micro-films from discrete nanoliter sessile droplets. The obtained micro-films show extremely uniform and intense color, enabling exceptional consistency in optical appearance across the entire array. The color can be controlled through the initial ink formulation, enabling the printing of polychromatic dot-matrix images. Moreover, the high surface-to-volume ratio of the micro-films and the intrinsic hydrophilicity of the natural building block allow for a dramatic real-time colorimetric response to changes in relative humidity. The printed CNC micro-film arrays overcome the existing issues of scalability, optical uniformity and material efficiency, which have held back the adoption of CNC-based photonic materials in cosmetics, interactive-pigments or anti-counterfeit applications.

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Acceptance Date
cellulose nanocrystals, cholesteric liquid crystals, colloidal self-assembly, humidity sensors, sessile droplets
Journal Title
Advanced Functional Materials
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Volume Title
Biotechnology and Biological Sciences Research Council (BB/K014617/1)
EPSRC (1648007)
European Research Council (639088)
Engineering and Physical Sciences Research Council (EP/N016920/1)
Engineering and Physical Sciences Research Council (EP/L015978/1)
Engineering and Physical Sciences Research Council (EP/L016087/1)
The European Research Council [ERC-2014-STG H2020 639088], the BBSRC David Phillips Fellowship [BB/K014617/1], the EPSRC [EP/L016087/1, EP/L015978/1, EP/N016920/1], and the Winton Programme for the Physics of Sustainability.
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