Abstract: The invention relates to an electromechanical transducer device (2, 2.1, 2.2, 2.3, 2.4) comprising at least one layer composite (4, 4.1) disposed between a first electrode (6) and at least one second electrode (8). Said layer composite (4, 4.1) comprises a first electro-active layer (10) and at least one second electro-active layer (12), an electret material 14, 14.1) being provided, at least in sections, between the first electro-active layer (10) and the second electro-active layer (12), and the electret material (14) has an electric charge which can be predefined.

Abstract: The present invention relates to a ferroelectret multi-layer composite (1) comprising at least two polymer films arranged one on top of the other and bonded together, wherein voids are formed between the polymer films, said voids being tubular channels, particularly running parallel to one another. The invention further provides a process for the production of a ferroelectret multi-layer composite with parallel tubular channels, and a device for carrying out the process for the production of the ferroelectret multi-layer composite according to the invention. In addition, the invention relates to a piezoelectric element containing a ferroelectret multi-layer composite according to the invention.

Abstract: The present invention relates to a piezoelectric polymer film element, in particular a polymer foil, comprising a polymer matrix, wherein hollow particles are arranged in the polymer matrix, and a process for the production of such a piezoelectric polymer film element, comprising the steps: A) provision of hollow particles and B) introduction of the hollow particles into a polymer matrix and C) shaping of the polymer matrix as a polymer film. The invention furthermore relates to an electromechanical converter comprising at least one first polymer film which comprises hollow particles as fillers.

Abstract: The invention relates to a method for producing double or multilayer ferroelectret with defined cavities by: structuring at least one first surface of a first polymer film (1) forming a height profile, applying ate least one second polymer film (5, 1?) to the structured surface on the first polymer film formed in step a), joining the polymer films (1, 1?, 5) to give a polymer film composite with the formation of cavities (4, 4?) and electrically charging of the inner surfaces of the cavities (4, 4?) formed in step c) with opposing electrical charges. The invention further relates to ferroelectret multilayer composites, optionally produced by said method, comprising at least two polymer films, arranged one over the other and connected to each other, wherein cavities are formed between the polymer films. A piezoelectric element comprising a said ferroelectret multilayer composite is also disclosed.

Abstract: The present invention relates to a ferroelectret multi-layer composite (1) comprising at least two polymer films arranged one on top of the other and bonded together, wherein voids are formed between the polymer films, said voids being tubular channels, particularly running parallel to one another. The invention further provides a process for the production of a ferroelectret multi-layer composite with parallel tubular channels, and a device for carrying out the process for the production of the ferroelectret multi-layer composite according to the invention. In addition, the invention relates to a piezoelectric element containing a ferroelectret multi-layer composite according to the invention.