Comparison of cellulose nanocrystal dispersion in aqueous suspension via new and established analytical techniques

To obtain a complete understanding of the properties of cellulose nanocrystal (CNC) suspensions, we not only need to be able to characterize the CNCs themselves but also be able to analyze their particle-particle interactions and spatial distribution. Here, three established techniques—dynamic light scattering, rheology and atomic force microscopy (AFM)—and two new techniques—interferometric scattering (iSCAT) microscopy and cluster-triggered emission (CTE) autofluorescence spectroscopy—are evaluated for their ability to determine whether a CNC suspension is well-dispersed. This study confirms that AFM height data, rheology, iSCAT microscopy and CTE autofluorescence spectroscopy are sensitive to the transition from agglomerates to individual CNCs, validating their suitability. Data from these four techniques also indicate that excessive sonication of CNC suspensions is feasible, potentially leading to undesirable nanoparticle degradation. These results confirm the applicability of both iSCAT microscopy and CTE autofluorescence spectroscopy for high throughput analysis of nanoparticle dispersion, which can potentially be employed during the industrial production of CNCs. Graphical abstract