Abstract

Nature mastered use of hierarchical structures over multiple length scales to produce multi- functional materials. Mimicking such organization and functionality from simple building blocks is a key challenge for man-made materials. A further overarching challenge is to bridge the different length scales to transfer the local structures to useful macroscopic materials properties. In my talk, I will address selected examples of self-assembling colloidal and polymer systems in nature and in vitro; For example inspired by the striking metallic blue shine on the Pollia Condensata and Margaritaria Nobilis with aligned cellulosic cell walls, we showed controlled self-assembly of cellulose nanocrystals, allow helicoidal-mimetic bulk materials in thin film form with digital coloration 1-3 . Cellulose derivatives also follow similar ordering and we translated those structures into colorimetric pressure sensors 4 and colorimetric timers 5 . Nanocelluloses also allow porous films towards efficient light scattering media, mimicking white beetles 6,7 . Our latest work focuses on using chitin building blocks together with different plasmonic nanoparticles to explore the production of metamaterials in the visible field as well as smart textiles with structural colour. In my talk, I will first give a summary of colour formation mechanisms used in Nature and explain how self-assembly and bio-mimicry principles work. The challenges in the scaling up, self-assembly dynamics and material palette will also be discussed 8.

References

1. Digital Color in Cellulose Nanocrystal Films- doi.org/10.1021/am501995e 2. Controlled, Bio‐inspired Self‐Assembly of Cellulose‐Based Chiral Reflectors, doi.org/10.1002/adom.201400112 3. Chiral optics of helicoidal cellulose nanocrystal films doi.org/10.1063/1.4978387 4. Biocompatible and Sustainable Optical Strain Sensors for Large‐Area Applications doi.org/10.1002/adom.201600451 5. Edible cellulose-based colorimetric timer, Abstracts of papers of the American Chemical Society 2019 6. Nanocellulose composites for electronic paper displays, Abstracts of papers of the American Chemical Society, 2015 7. Anomalous‐Diffusion‐Assisted Brightness in White Cellulose Nanofibril Membrane doi.org/10.1002/adma.201704050 8. Biomimetics of Structural Colours: Materials, Methods and Applications doi.org/10.1039/9781788015806-00167