In-Situ Characterization of Stress Development in Gelatin Film During Controlled Drying

Abstract

Drying of gelatin films was studied by an in-situ cantilever beam method combined with spectroscopic ellipsometry, enabling measurement of the stress development, film shrinkage and compositional change during the drying process. Experiments are carried out under different drying conditions (such as drying extent variation, drying rate variation). The film experiences stress relaxation that indicates visco-elastic relaxation or plastic deformation happened during drying process. Plastic deformation is verified by carefully reversing the drying process, however, the plastic deformation accompanied by visco-elastic relaxation complicates the case of finding the value of the yield stress.