High-Throughput\nMolecular Dynamics Study and Turbidity\nAnalysis on Clustering and Agglomeration of Cellulose Nanocrystals\nin Suspensions

The dispersion of cellulose nanocrystals (CNCs) in suspensions\ndetermines the quality of the CNC-reinforced composites. Before being\nmixed into the composite matrix, stable suspensions must maintain\na well-dispersed state, requiring proper design strategies to prevent\nagglomeration and precipitation. Considering the volume fraction,\naspect ratio, and zeta potential, this paper proposes a coarse-grained\nmodel to simulate CNC clustering and an experimental program to observe\naccelerated precipitation of CNCs. High-throughput molecular dynamics\nsimulations yield a diagram of clustering time plotted against aspect\nratio, zeta potential, and volume fraction of CNCs. Turbidity analysis\nwith centrifugation-accelerated tests shows that precipitation occurs\nonly after clustering and agglomeration are completed and that centrifugation\nrarely accelerates clustering. Clustering of short chains instantly\nleads to agglomeration, whereas clustering of long chains features\ndelayed agglomeration, which can be triggered by centrifugation. Zeta\npotential is found to be the most critical factor affecting clustering,\nagglomeration, and precipitation. The findings provide critical insights\ninto the conditions that favor stable CNC suspensions, which are essential\nfor preparing well-dispersed suspensions and improving the composite\nmaterial performance.