A method for testing the elastic modulus of single cellulose fibrils via atomic force microscopy

In this study, the atomic force microscope (AFM) was used to measure the nano-Newton forces and nanometer deflections of cellulose fibrils by nano-scale three-point bending tests, and the elastic moduli of single fibrils were evaluated by a pure bending formula. In calculating the deflections of fibrils during these tests, it became apparent that portions of the AFM tips penetrated the cellulose fibril surfaces was a factor that had to be taken into account. The elastic modulus of cellulose fibrils, of diameter approximately 170 nm isolated from Lyocell fibers by high intensity ultrasonication was evaluated to be 93 GPa.