Abstract: For a procedural functional element formed from a stack of films or plates provided with microstructures, on at least one side of the films a thin film coating is provided, which extends into the microstructures from the coated side so that the thin film coating forms both a surface seal between films lying on one another and a protective layer for the material of the films against aggressive media.

Abstract: A heat exchanger (1), in particular a micro heat exchanger, constructed from a stack of films or plates (F), wherein in the individual plates (F), throughholes (4, 5, 7, 8) and channels (2, 3) extending in the plane of the plates are formed, and the plates (F) are arranged over one another such that the channels (2, 3) in successive plates (F) intersect, a first fluid (P) flows through the channels (2) of a plate (F) and a second fluid (W) through the channels (3) in the adjacent plate (F), at the outsides of the resulting block of intersecting channels (2, 3) supply and discharge pipes are formed by the throughholes (4, 5, 7, 8), and wherein at least one of the two fluids (P, W) flows through the channels of the relevant plate in an antiparallel manner or in the counter direction alternately.