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

Polyacrylamide hydrogels (PAH gel) and polydimethylsiloxane (PDMS, an elastomer) are two soft materials often used in cell mechanics and mechanobiology, in manufacturing lab-on-a-chip applications, among others. This is partly due to the ability to tune their elasticity with ease in addition to various chemical modifications. For affine polymeric networks, two (of three) elastic constants, Young's modulus (), the shear modulus (), and Poisson's ratio (ν), describe the purely elastic response to external forces.