Microstructure and stress propagation in the nematic glass phase of colloidal cellulose nanocrystals

Suspensions of cellulose nanocrystals (CNC's) in low ionic strength aqueous solutions can undergo an isotropic-nematic phase transition due to the anisotropic nature of CNC's. At concentrations above a certain threshold, when the system is well into the nematic regime but far below the maximum stable concentration, these suspensions can form a soft solid with a modulus of approximately 500 Pa. The nematic phase is not homogeneous throughout this system but instead forms many domains, each consisting of collectively aligned CNC's with an average orientation that differs from neighboring domains. This work seeks to understand the mechanical contribution of the domain structure, as observed through cross polarization and boundary stress microscopy, to the macroscopic properties measured through bulk rheology.