Strain energy density of VO2-based microactuators

• VO2 was deposited on a single-crystal silicon microactuator by laser ablation.
• Microactuator curvature was experimentally measured with a light scattering method.
• Strain and stress changes of up to −0.32% and −510 MPa, respectively, were obtained.
• Strain energy density values of up to ~8.1 × 105 J/m3 through ~15 °C were obtained.
• Hysteresis evolution of strain, stress and strain energy density was studied.

The strain, stress and strain energy density of a vanadium dioxide (VO2)-based microactuator were obtained from experimental curvature measurements as a function of temperature. The study revealed fully reversible strain and stress changes of up to −0.32% and −510 MPa, respectively, and a maximum strain energy density of approximately 8.1 × 105 J/m3 through a temperature window of only 15 °C. The method for obtaining the strain energy density in this work is more accurate than the ones presented previously in the literature. The obtained values were validated with a temperature-dependent solid mechanics finite element analysis simulation. Microactuator performance was also studied inside its hysteretic region through a series of heating and cooling cycles, providing a more complete performance analysis of the device properties.