Mechanical bending properties of sodium titanate (Na2Ti3O7) nanowires

Abstract

We report on the mechanical properties of sodium titanate nanowires (Na₂Ti₃O₇ NW) through a combination of bending experiments and theoretical analysis. Na₂Ti₃O₇ NWs with lateral dimensions ranging from 20–700 nm were synthesized by a hydrothermal approach. A focused ion beam (FIB) was used to manipulate the selected Na₂Ti₃O₇ NW over a hole drilled in an indium tin oxide substrate. After welding the nanowire, a series of bending tests was performed. It was observed that the Na₂Ti₃O₇ NW exhibits a brittle behavior, and a nonlinear elastic deformation was observed before failure. By using the modified Euler–Bernoulli beam theory, such nonlinear elastic deformation is found to originate from a combination of surface effects and axial elongation (arising from the bending deformation). The effective Young's modulus of the Na₂Ti₃O₇ NW was found to be independent of the wire length, and ranges from 21.4 GPa to 45.5 GPa, with an average value of 33 ± 7 GPa. The yield strength of the Na₂Ti₃O₇ NW is measured at 2.7 ± 0.7 GPa.