10,000 publications from this institution
Few engineering materials are limited by their strength; rather they are limited by their resistance to fracture or fracture toughness. It is not by accident that most critical structures, such as bridges, ships, nuclear pressure vessels and so forth, are manufactured from materials that are comparatively low in strength but high in toughness. Indeed, in many classes of materials, strength and toughness are almost mutually exclusive. From a fracture‐mechanics perspective, the ability of a microstructure to develop toughening mechanisms acting either ahead or behind the crack tip can result in resistance‐curve (R‐curve) behavior where the fracture resistance actually increases with crack extension; the implication here is that toughness is often developed primarily during crack growth and not for crack initiation. Biological materials are perfect examples of this; moreover, they offer microstructural design strategies for the development of new materials for structural applications demanding combinations of both strength and toughness.
We report the integration of inorganic nanotubes into metal-oxide-solution field effect transistors (FETs) which exhibit rapid field effect modulation of ionic conductance. Surface functionalization, analogous to doping in semiconductors, can switch the nanofluidic transistors from p-type to ambipolar and n-type field effect transistors. Transient study reveals the kinetics of field effect modulation is controlled by ion-exchange step. Nanofluidic FETs have potential implications in subfemtoliter analytical technology and large-scale nanofluidic integration.
