Nanocellulose alignment under complex deformation field studied by a fluidic four roll mill and small angle X-ray scattering

The understanding of flow properties of cellulose nanomaterials is essential to tailor the properties of wood-based materials produced by 3D printing, wet-spinning, etc. We conducted a study in a fluidic four-roll mill (FFoRM) device by scanning small angle X-ray scattering (SAXS) to study the effect of concentration, flow rate, and flow type on the orientation of the cellulose nanofiber and cellulose nanocrystal suspensions. We found that the differences in rod-rod interactions and flexibility play an important role in the fluid’s macroscopic response to similar flow histories. The analysis of the measured collective structure in the dispersions (i.e., interparticle correlations between rods) provides the nanostructural explanation for these differences. These new measurement and analysis techniques produce large data sets that hold promise toward advancing process-structure-property models and the inverse design of processes to produce targeted nanostructures.