Linking Film Structure and Mechanical Properties in Nanocomposite Films Formed from Dispersions of Cellulose...

Cellulose nanocrystals (CNCs) are unique, lightweight materials that possess high elastic modulus and tensile strength, making them of great interest in the formation of nanocomposite materials. However, efficient design of the composite material is essential in translating the mechanical properties of the individual CNCs into the nanocomposite film. In this work, we demonstrate the formation of structured CNC/acrylic dispersions by physical blending of the anionic CNCs with charged acrylic latex particles. By blending with large cationic latex particles, the CNCs adsorbed onto the acrylic latex surface while blending with small latex particles led to the inverse structure. Films were cast from these dispersions and the physical properties were compared with the aim of understanding the influence of the initial structure of the hybrid dispersion on the structure of the final film. A significant difference in the mechanical properties was observed based on the position of the CNCs in the initial dispersion. Adsorption of latex particles onto the CNC surface led to a random distribution of nonconnected CNCs, which contributed little to improving the Young's modulus, while adsorption of CNC onto the latex led to a honeycomb CNC network and a large increase in the Young's modulus. This work underlines the importance of particle structure on the structure and mechanical properties of nanostructured films.