Herein described is a device for controlling fluid motion in a micro/nanofluidic structure of channels, comprising: a structured volume of material (30), bearing a predetermined configuration of micro/nanofluidic channels (C) for holding and transferring amounts of fluids, adapted to define at least one fluid inlet (IN) and at least one fluid outlet (OUT), and presenting a hydrophobic behaviour for the fluids to be handled; and a substrate (31) made of material with piezoelectric properties, coupled to the abovementioned configuration of micro/nanofluidic channels, bearing means for active control of the motion of an amount of fluid, including transducer means (T1-T6) which comprise at least one pair of interdigitated electrodes applied on the substrate (31), which are arranged to selectively generate a surface acoustic wave adapted to propagate on the substrate (31) and interact with the amount of fluid. The transducer devices (T1-T6) are arranged in proximity to a fluid outlet (OUT) of the configuration of channels in such a manner to generate a surface acoustic wave propagating from the fluid outlet (OUT) to a fluid inlet (IN) of the abovementioned configuration and, due to the hydrophobic condition in the channel (C) in which an amount of fluid is localised, determine an effective force at the air-liquid interface where the acoustic wave meets the liquid, whereby the motion of the amount of fluid is induced towards the direction opposite to the surface acoustic wave propagation direction.