Smoothed Dissipative Particle Dynamics Model for Predicting Self-Assembled Nano-Cellulose Fibre Structures David Vidal and Tetsu Uesaka FPInnovations, Pointe-Claire, Québec, CANADA Nano-cellulose fibres in suspension/gel states are known to have complex structures, depending on, e.g., concentration and ionic strength. These complex structures pose both opportunity (creating novel functional structures) and challenges (difficult rheology and processability). To better assess their impacts on the formation of nano-cellulose structures, a novel particle-based method has been proposed based on Smoothed Dissipative Particle Dynamics. This numerical approach treats both fluid and solid phases, in a unified way, as a set of particles exchanging momentum and/or interacting through Derjaguin-Landau-Verwey-Overbeek (DLVO) potentials. Additionally, nano-cellulose fibres are represented as strings of solid particles connected through extensional/bending springs. Brownian motion is also accounted for as a dissipative term. Preliminary results already showed that self-assembled structures created by the nano-cellulose fibres are extremely sensitive to the type of interactions (e.g., electrostatic force interactions), the intensity and spatial distance of the interactions, and the concentration and configuration of nano-cellulose fibres. By using this method, it is thus possible to investigate the Figure 1 - Small-scale example of SDPD simulation of fibres starting to be sheared under a Couette flow. Here fibres are represented by blue round cylinders. The small spheres locate the centers of mass of so-called fluid particles interacting with the fibres. The color of spheres indicates the magnitude of their respective velocity, the warmer the color, the higher the velocity.