Effect of Fiber Alignment on Optical Properties of Cellulose Nanocrystal Films

Cellulose based materials display positive uniaxial birefringence. How cellulose is processed and manufactured can maximize this anisotropy. In this study different processing techniques were used to produce cellulose nanocrystal (CNC) thin film. Different processing conditions and techniques were used to align CNC fiber in CNC thin film. After CNC based film was produced, it was optically tested for fiber alignment and birefringent behavior. This study shows that shear casting can align CNC fiber and improve birefringent effect of CNC based materials. Optical studies also helped determine orientation and density distribution of fiber at different orientations. It was found that the birefringence properties in CNC based composite materials are dependent on the incident light wavelength.