Rheology is used to analyze cellulose nanocrystals dispersion state in water.
•
Different flow geometries are studied to highlight the sampling volume influence.
•
An ultrasonication timeline is defined to better understand the dispersion process.
•
Never-dried and spray-dried suspensions are compared to assess dispersion state.
•
A well-dispersed spray-dried CNC concentrated suspension is successfully obtained.
Abstract
Cellulose nanocrystals (CNCs) are promising biomaterials, but their tendency to agglomerate when dried limits their use in several applications. Ultrasonication is commonly used to disperse CNCs in water, bringing enough energy to the suspension to break agglomerates. While the optimized parameters for sonication are now well defined for small volumes of low concentration CNC suspensions, a deeper understanding of the influence of the dispersing process is needed to work with larger volumes, at higher concentrations. Herein, rheology is used to define the distribution and dispersion states upon ultrasonication of a 3.2 wt% CNC suspension. After considering the importance of the measurement sampling volume, the behavior of a more concentrated suspension (6.4 wt%) is examined and compared with a never-dried suspension of the same concentration to validate the dispersion state.