Title
Self-assembly of cellulose nanocrystals with fluorescent agent in iridescent films
Authors
RAPHAEL BARDET CECILE SILLARD NACEUR BELGACEM and JULIEN BRAS

Published Volume 49 Issue 7-8 July-August
Keywords nanocellulose, cellulose nanocrystals, iridescence, fluorescence, film

Abstract
Sulfated cellulose nanocrystals (CNCs) undergo self-organization in concentrated suspensions, leading to the formation of an iridescent film under specific drying conditions. In this study, CNCs were combined with the optical brightening agent (OBA), distyrylbiphenyl sulfonate (DSBP), which imparts fluorescence to the iridescent film as an additional property. The influence of DSBP on the CNC suspension is limited, thus the self-organization and the structural coloration (iridescent) of the film obtained by simple evaporation are preserved. The first section of the study outlines the influence of DSPB on the CNC suspension based on various analyses, including zeta potential measurements, dynamic light scattering (DLS), quartz crystal microbalance (QCM), and atomic force microscopy (AFM). From fluorescence spectroscopy, the amount of DSPB labeled onto the CNCs is determined to be ~18 µmol/g. Solid films based on DSPB-labeled CNC were also produced and characterized via UV spectroscopy. These films appear both colored in natural light, due to preservation of the self-assembly of CNC, and fluorescent under UV-illumination because of the fluorescent agent.