The use of copolymers obtainable by the radically initiated polymerization of A) 50 to 99. To achieve this, nanoparticles are added to a base substance. The arrangement is such that the pressure in each of the actuation outputs is controllable selectively either in mode a) jointly, with the link valve enabling air flow between the actuation outputs or in mode b) independently, with the link valve blocking air flow between the brake actuation outputs. The coupler is connected to the closure to transmit fluids to a fluid system. A second buffer layer is formed between the conductive film and at least one of the center electrode and the ground electrode.