Effect of temperature and pH on nanostructural and nanomechanical properties of chitosan films

In the present study, we have used PeakForce-QNM AFM mode to investigate nanostructural and nanomechanical properties of chitosan films at the nanoscale. Our data demonstrated that the pH of the chitosan solution and the curing temperature of the films are key factors that affect their structural and mechanical properties. AFM roughness and Young's modulus measurements showed that even small changes in pH and temperature could lead to different structure and mechanics of the film. Meanwhile, the changes in the films’ surface free energy were negligible upon variations in pH and drying temperatures. Chitosan films prepared from a solution of pH 4.3 and dried at 60 °C were found to be very smooth and demonstrated very good mechanical properties. The results from this study will be used to develop conducting chitosan films for cell cultures that will help in understanding some cell functions.