Flexible and bendable acoustofluidics based on ZnO film coated aluminium foil

ZnO coated Al foil of 50 μm thick was used to fabricate flexible and bendable acoustofluidic devices with various wavelengths (from 64 to 800 μm). Different acoustic wave modes (including Lamb waves and Rayleigh waves) were obtained experimentally and verified from theoretical analysis. Flexibility and deformability of the ZnO/Al foil acoustic wave devices were demonstrated by (1) deformation testing by bending the acoustic wave devices with strain values up to 1.375%; (2) fatigue testing by bending the devices for 2000 cycles. Using Lamb waves and Rayleigh waves generated from the ZnO/Al foil acoustofluidic devices, functions of droplet streaming and pumping were demonstrated using the flexible acoustic wave devices under different bending and twisting positions.