  Cellulose is the most abundant bio-polymer on earth. Cellulose fibres, such
as the one extracted form cotton or woodpulp, have been used by humankind for
hundreds of years to make textiles and paper. Here we show how, by engineering
light matter-interaction, we can optimise light scattering using exclusively
cellulose nanocrystals. The produced material is sustainable, biocompatible
and, when compared to ordinary microfibre-based paper, it shows enhanced
scattering strength (x4) yielding a transport mean free path as low as 3.5 um
in the visible light range. The experimental results are in a good agreement
with the theoretical predictions obtained with a diffusive model for light
propagation.
