Versatile specimen-grating fabrication technique for moiré method based on solute-solvent separation soft lithography

Abstract

A specimen-grating fabrication technique based on solute-solvent separation soft lithography (3S soft lithography) is reported. Both transfer and zero-thickness gratings can be fabricated using this approach. A two-layer hybrid polydimethylsiloxane (PDMS) stamp is designed to increase the stamp in-plane stiffness without degrading the off-plane flexibility. The frequency uniformity, micromorphology, thickness, and shear lag of each fabricated grating is characterized. The application ranges of the fabricated transfer and zero-thickness gratings are determined via experiments. As examples of typical applications, the fabricated gratings are used in moire interferometry and scanning moire experiments to determine the residual stress and crack opening displacement.