Optimization of the performances of SU-8 organic microcantilever resonators by tuning the viscoelastic properties of the polymer

This paper describes a promising method to improve the performances of organic resonant microcantilevers. This method is based on the tuning of the viscoelastic properties of the material by controlling internally the temperature of the structure. Actuation of the SU-8 free-standing microstructures has been integrated by means of electromagnetic forces while a static resistive thermal effect, obtained by applying a DC current in a conducting path, has been used to control the temperature of the structure. Investigation of the electromagnetic and thermal influence on the static and dynamic behavior has shown that the thermal effect dominates the electromagnetic one in static mode and inversely in dynamic mode. As a result, by applying a constant heating of the structure, the viscoelastic properties of polymers have been tuned, and the quality factor of SU-8 microcantilevers has been thereby enhanced by a factor 2 in air and 2.25 in liquid.