Quasi-hemispherical voids micropatterned PDMS as strain sensor

Polydimethylsiloxane elastomers are largely employed in soft lithographic replication for the realization of microstructures that find application in microfluidic and micro-engineering. In the last years micro and nano patterned ordered structures have gained remarkable attention for their employment in the development of biomedical devices, smart displays, chemical and physical sensors. Here a 2D quasi-hemispherical micro voids elastomeric grating has been successfully realized and it has been demonstrated that this structure can be considered a simple, low cost reversible strain sensor. Specifically, the sensor permits simultaneous determination of the strain-stress information analyzing the voids' spacing based on Debye diffraction distance. A model from Continuum Mechanics has been employed in order to assess its optical response, meaning to predict the mechanical deformation of the patterned surface of the sample and to corroborate the accuracy of the optical measurements. The results demonstrate that the 2D quasi-hemispherical micro voids sensing system can be considered as a complementary approach respect to the traditional strain sensors.