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

Abstract

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 μJ/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.

Facile Determination of the Poisson’s Ratio and Young’s Modulus of Polyacrylamide Gels and Polydimethylsiloxane

“…We observe a similar behavior for PDMS elastomer, that is, ν increased with increasing degree of cross-links. Our ν values for PDMS elastomer and others ,, are summarized in Figure b.…”

“…Soft hydrogels and many elastomers used in bioengineering applications are, however, typically compressible, some very much so. However, the literature addressing experimental determination of ν for important soft materials such as polyacrylamide gels (PAH gel, also sometimes referred to as PAA gels in the literature) and polydimethylsiloxane (PDMS elastomer) is surprisingly limited when compared to the literature reporting values of E and G . − For these materials, the Poisson’s ratio ν deviates significantly from 0.5 and attains values ranging between 0.25 and 0.49, − , depending on the molecular weight and the degree of cross-linking of their constituents …”

“…Elastic properties of the PDMS elastomer were also measured recently. Laser-engraved grid patterns were used to obtain ν, E , and G by optically measuring the grid pattern distortion when the specimen was mechanically stretched . Alternatively, ν can also be determined by exploiting thermal expansion and measuring surface deformations.…”

Development of eye phantom for mimicking the deformation of the human cornea accompanied by intraocular pressure alterations

“…The Young’s modulus of the PDMS phantom materials was adjusted to approximately 380 kPa by controlling the composition of the liquid PDMS mixture (Sylgard 184, Dow Corning, the weight ratio of the silicone elastomer to the curing agent was 22:1) 29 . The Young’s modulus, representing the linear elasticity, was measured by a tensile method 30 . PDMS samples for tensile stress testing were prepared according to the ASTM D 412 standard.…”

Advances in design and manufacture of stretchable electronics

“…where W is the load applied to the sample by a spherical probe with radius R, and RD is the measured relative displacement. 24) This is an approximation of the ratio of change in axial strain (dε axial ) to the change in transverse strain (dε trans ) under uniaxial extension 25) as described by…”