Spatially and flow-sensitive alignment of cellulose nanocrystals during nanoscale confinement

Film behaviour is dominated by fluid flow (hydrodynamic force) for thick films, and this controls initial stages of film drainage. However, a transition occurs later in film drainage whereby long-range structural forces, from confined particle-particle interactions, sculpts thin film morphology. Bulk phase properties measured using rheology and small-angle neutron scattering provide complementary insight into lubrication dynamics, indicating that CNC anisotropy couples with flow and confinement conditions present within thin films, resulting in spatially-sensitive induced orientation. This study demonstrates the nuanced role of anisotropic features in confined flow and suggests opportunities for flow-based orientational control of sustainable nanomaterials.