A device forming a manometer, configured to measure pressure of a biphasic fluid in a fluidic network, including: a first channel inside which a biphasic fluid is able to flow; a second channel emerging into the first channel, wherein the second channel is blind, with each of its dimensions less than capillary length of the fluid's liquid phase, and with at least one of its lengthways wall having a surface energy gradient that decreases from its inlet to the end. The surface energy gradient enables the wetting angle of the meniscus of the fluid's liquid phase to be increased in the blind channel from its inlet to the end. Such a device may find application to measurement of pressure of a biphasic fluid in a heat exchanger or in a fuel cell.