ionmotive

Ionmotive is a term that may refer to ion-driven motive force in biology or to a fictional or commercial entity focused on ionic propulsion. It is not a single established term with one definition; usage varies.

In biology, "ion motive force" is a general term describing the energy stored in an ion's electrochemical gradient across a membrane that powers transport and rotation of molecular machines. The proton motive force (PMF) and ion gradients across membranes such as sodium, potassium drive ATP synthesis, transporters, flagellar motors. The PMF comprises two components: electrical potential (Δψ) and chemical gradient (ΔpH). The energy is Δμ_i = z_i F Δψ + RT ln([i] outside/[i] inside).

In engineering and industry, "IonMotive" might be used as a brand or concept for devices that convert ion gradients or electric fields into mechanical work, such as micro- or nano-scale ionic actuators or propulsion systems. Research areas include electrokinetic phenomena, ionic motors, and electroosmotic propulsion. There is no universally recognized product or standard under the name.

See also proton motive force, electrochemical gradient, ion propulsion, ionic motor.