Assembly of cellulose nanocrystals and clay nanoplatelets studied by time-resolved X-ray scattering

Abstract

Time-resolved small-angle X-ray scattering (SAXS) was used to probe the assembly of cellulose nanocrystals (CNC) and montmorillonite (MNT) over a wide concentration range in aqueous levitating droplets. Analysis of the SAXS curves of the one-component and mixed dispersions shows that co-assembly of rod-like CNC and MNT nanoplatelets is dominated by the interactions between the dispersed CNC particles and that MNT promotes gelation and assembly of CNC, which occurred at lower total volume fractions in the CNC:MNT than in the CNC-only dispersions. The CNC dispersions displayed ad∝ϕ−1/2scaling and a low-qpower-law exponent of 2.0-2.2 for volume fractions up to 35%, which indicates that liquid crystal assembly co-exists and competes with gelation.