Optical anisotropy assessment in nanopaper sheets by imaging Mueller matrix polarimetry

Pristine nanopaper sheets have been produced by the drop-casting process using water-based cellulose nanocrystals solutions with different solute concentrations and hydrogen potential values of the solvent. In order to assess the optical properties associated to the microscopic structure of the resulting substrates, imaging Mueller matrix polarimetry was implemented. Even though the depolarizing features expected in this kind of media, optical anisotropic parameters were measured at microscopic level. It was found that spatial distribution of birefringence depends not only on the raw material nanoconformation, but also on the applied processing method. Nanopaper structural evaluation can help in understanding and optimizing optical response of sensing devices supported in these multifunctional materials.