Identification of the electro-elastic coupling from full multi-physical fields measured at the micrometer scale

Fabien Amiot (1) , François Hild (2) , Frederic Kanoufi (3) , Jean Paul Roger (4)

1 MIC-DTU - Mikroelektronik Centret
2 LMT - Laboratoire de Mécanique et Technologie
3 LECA - Laboratoire Environnement et chimie analytique
4 LSLP - Laboratoire de Spectroscopie en Lumière Polarisée

Metal coated micro-cantilevers are used as transducers of their electrochemical environment. Using the metallic layer of these cantilevers as a working electrode allows one to modify the electro-chemical state of the cantilever surface. Since the mechanical behavior of micrometer scale objects is significantly surface-driven, this environment modification induces bending of the cantilever. Using a full-field interferometric measurement set-up to monitor the objects then provides an optical phase map, which is found to originate from both electro-chemical and mechanical effects. The scaling of the electro-chemically-induced phase with respect to the surface charge density is modeled according to Gouy-Chapman-Stern theory, whereas the relationship between the mechanical effect and the surface charge density is analyzed. An identification technique is described to determine a modeling of the electro-elastic coupling and to identify the spatial charge density distribution from full-field phase measurements. Minimizing the least-squares gap between the measured phase and a statically admissible phase field, the mechanical effect is found to be charge-driven. The charge density field is also found to be singular on the cantilever edge, and the shear stress vs. charge density is found to be non-linear.

Domaines: Mécanique des solides [physics.class-ph]; Mécanique des solides [physics.class-ph]; Optique [physics.optics]; Chimie-Physique [physics.chem-ph]

Fabien Amiot, François Hild, Frederic Kanoufi, Jean Paul Roger. Identification of the electro-elastic coupling from full multi-physical fields measured at the micrometer scale. Journal of Physics D: Applied Physics, 2007, 40, pp.3314-3325. ⟨hal-00144426⟩