Rheological interpretation of intermediate physical state of gel and liquid crystalline phases in cellulose solution and their synergetic effects on the mechanical property

In this study, the physical states of cellulose in 1-allyl-3-methylimidazolium chloride (AmimCl) were analyzed via rheological observations under three different conditions: namely, steady state, small amplitude oscillatory shear, and large amplitude oscillatory shear conditions. The physical state of the solution changed from an isotropic phase to a gel structure via a liquid crystalline (LC) phase as the concentration increased. The rheological analysis showed that the 16 wt% solution was physically gelled in the anisotropic phase. This instantaneous gelation at the LC phase markedly enhanced the mechanical performance of the film obtained from the solution. This study provides a fundamental strategy for significant improvement in the mechanical properties of cellulose fibers or films.