Gradual bending of a microcantilever with molecular coverage is referred to as operation in the ‘static mode’. Various environments are possible, such as vacuum, ambient environment and liquids. In gaseous environment molecules adsorb on the functionalized sensing surface and form a molecular layer, provided there is affinity for the molecules to adhere to the surface. Polymer sensing layers show a partial sensitivity, because molecules from the environment diffuse into the polymer layer at different rates, mainly depending on the size and solubility of the molecules in the polymer layer. By selecting polymers among a wide range of hydrophilic/hydrophobic ligands, the chemical affinity of the surface can be influenced, because different polymers vary in diffusion suitability for polar/unpolar molecules. Thus, for detection in gas phase, the polymers can be chosen according to the detection problem, i.e. what the applications demand. Typical chemicals to be detected are volatile organic compounds (VOCs).

Static-mode operation in liquids, however, usually requires rather specific sensing layers, based on molecular recognition, such as DNA hybridization or antigen-antibody recognition.

Static mode exploiting surface stress changes