Engineered pigments based on iridescent cellulose nanocrystal films
Raphael Bardet1, Francine Roussel2, Stéphane Coindeau2
1University of Grenoble Alpes, LGP2, F-38000 Grenoble, France; CNRS, LGP2, F-38000 Grenoble, France.
Carbohydrate Polymers
|March 31, 2015
Summary
Researchers developed biobased iridescent pigments from cellulose nanocrystal (CNC) films. Post-treatments enhance pigment stability, enabling anticounterfeiting features in packaging.
Area of Science:
- Materials Science
- Nanotechnology
- Biomaterials
Background:
- Cellulose nanocrystals (CNCs) offer potential for biobased materials.
- Iridescent pigments can be derived from nanostructured CNC films.
- Sulfate groups in CNCs can limit pigment stability and performance.
Purpose of the Study:
- To develop a simple method for producing biobased iridescent pigments from CNC films.
- To address limitations of thermal degradation and water redispersion in CNC-based pigments.
- To explore post-treatment strategies for enhancing pigment properties.
Main Methods:
- Formation of nanostructured films from CNC liquid-crystalline suspension.
- Dry grinding of CNC films to produce flake-like pigments.
- Post-treatment via vacuum overdrying to remove sulfate groups.
- Addition of NaCl to increase ionic strength for improved water dispersibility.
Main Results:
- Biobased iridescent pigments with flake-like morphology (25 μm thickness) were produced.
- Vacuum overdrying effectively removed sulfate groups, improving thermal stability.
- Increased ionic strength reduced pigment mass loss in aqueous media.
- Post-treatments significantly enhanced the stability and performance of CNC-based iridescent pigments.
Conclusions:
- A straightforward method for creating stable, biobased iridescent pigments from CNC films is established.
- Post-treatment strategies effectively overcome sulfate group-related limitations.
- Engineered CNC-based pigments are suitable for anticounterfeiting applications in packaging.
