Surface mechanics and full-field measurements for micromechanical sensors

Many proofs of concept studies have established the mechanical sensitivity of functionalized microcantilevers to a large spectrum of target molecules. However, moving to real-life applications also requires the monitored mechanical effect to be highly specific. On the other hand, describing the involved surface effects in the continuum mechanics framework is still challenging. Several attempts to overcome the "surface stress" failure to satisfy field equations tend to show such a description has to be non-local, so that at least one 'characteristic lenghth' parameter has to be used. The consequence is towfold : first, suited modelings have to be developed to describe the surface effects at the cantilever scale ; and second, the involved characteristic length is (thermodynamically) connected to the molecular mechanisms at the cantilever surface, and may therefore be a key parameter for the target molecules identification. This large amount of data obtained using full-field set-ups is redundant from the machanical point-of-view, and this redundancy may be used to identify some of the key parameters describing the mechanical surface effects. (C) 2012 Published by Elsevier B.V. Selection and/or peer review under responsibility of H.D. Espinosa and F. Hild.