Poisson’s ratio measurement through engraving the grid pattern inside poly(dimethylsiloxane) by ultrafast laser

This work demonstrates an application of ultrafast laser processing to engrave a grid pattern for evaluating mechanical properties. No observable changes in the material properties caused by laser engraving were confirmed if the grid pattern is engraved with laser energy of 0.21 μ J/pulse and pulse repetition rate of 1 kHz. The shape changes of grid pattern directly reveal whether the deformation accompanied with stretching is uniaxial or not. By analyzing the optical images of the grid pattern, Poisson ratio, Young’s modulus, and shear modulus of poly(dimethylsiloxane) (PDMS) with a weight percent of curing agent of 9% were estimated to be 0.49989 ± 0.00111, 1.45 ± 0.01 MPa, and 0.725 MPa, respectively. The comparison of the current results with the literature values suggests that the proposed method is appropriate to provide quantitative mechanical properties of soft materials with high accuracy.