Polarized Light in the Contact Free Determination of Thermal Expansion of Organized Cellulose Nanocrystal Materials

The number of applications using cellulose nanocrystals (CNCs) has been consistently increasing due to their sustainable character and unique set of properties. The thermal stability of CNC films has been recently explored by determining the coefficient of thermal expansion (CTE), where optical response under polarized light was employed to highlight textural features required for digital image correlation calculations.¹ The technique has also been extended to other imaging modes such as bright field and phase contrast in different polymers² Major part of the optical and in-plane thermo mechanical properties in CNC films are highly correlated to the structure generated by the lyotropic character of aqueous suspensions.