Effects of pH and concentration on the phase transition behavior of cellulose nanocrystal(CNC)suspensions were studied,and the morphological characteristics of the CNC liquid crystal phase were observed by polarizing microscopy.Moreover,the phase diagram of the nematic phase,cholesteric phase,and birefringence glass phase formed by CNC was obtained.The rheological properties of the CNC systems were measured by steady-state shear and large amplitude oscillatory shear.The relationship between system rheological behavior and microstructure evolution was analyzed using Fourier rheology.The result shows that the addition of acid or alkali can shield the electrostatic repulsion between the CNCs,which induces gelation and increasing the nonlinear viscoelasticity of the system.As a result,the range of the nematic phase and cholesteric phase decreases.
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