Water's tensile strength measured using an optofluidic chip†
In this paper, for the first time, the tensile strength of water is directly measured using an optofluidic chip based on the displacement of air–water interface deformation with homogeneous nucleation. When water in a microchannel is stretched dynamically via laser-induced shock reflection at the air–water interface, the shock pressures are determined by measuring the displacements of the deformed interface. Observation of the vapor bubbles is used as a probe to identify the cavitation threshold with a critical distance, and the tensile strength of water at 20 °C is measured to be −33.3 ± 2.8 MPa. This method can be extended to investigate the tensile strength of other soft materials such as glycerol, which is measured to be −59.8 ± 10.7 MPa at 20 °C.