Effect of chain length on nanomechanics of alkanethiol self-assembly

The ability to generate nanomechanical cantilever motion from molecular interactions between analytes and immobilized receptors offers a unique platform for chemical and biological sensor development. A fundamental understanding of the origins of nanomechanical motion, however, is essential for developing reliable and reproducible sensors. We have investigated the nanomechanical bending of microfabricated cantilevers during the immobilization of alkanethiols of different chain lengths in the liquid phase. The bending of the cantilevers has been monitored using both piezoresistive and optical readout approaches. Our results suggest that the surface packing density in a liquid medium is largely affected by the length of the chains, which will have a profound influence on sensor sensitivity.